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1968 Mustang C4 Transmission weak into gear

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CoupeBoy
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1968 Mustang C4 Transmission weak into gear

Post #1 by CoupeBoy » Thu Jun 02, 2016 6:10 pm

I just drove my '68 Mustang for the first time in a long time, and it is acting oddly.

When taking off from a complete stop it acts like it isn't going to engage the clutches, and then for the first few feet it feels loose, then it acts normally.
When it shifts up into second it is almost like the 2nd gear isn't engaging solidly, same with the shift into 3rd gear.
When in 3rd gear and then I step on the accelerator to downshift, the transmission does downshift, but the engine speeds up without any actual improvement in forward momentum.
Manually downshifting acts 'normal'

I checked the fluid level, it is over full and NOT burnt.
Tonight I hope to drop the pan, I'll put in a new trans filter and top off the fluids to see if that has any affect.

Any other ideas?

Thanks,
-ron
1968 Mustang Daily Driver Rebuild (on hold for the Season 3/1/2015)
1963.5 Falcon Convertible Build (just getting started 3/15/2015)
Case 1830 Skidsteer FordSix Repower Thread (started 4/4/2015)
1970 170/C4
1967 200/C4
1965 240/bellhousing/flywheel/clutch/3.03 bell pattern
1975 250/flexplate
1975 300/flywheel

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Re: 1968 Mustang C4 Transmission weak into gear

Post #2 by CoupeBoy » Thu Jun 02, 2016 6:44 pm

It shifts firm into reverse.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #3 by B RON CO » Thu Jun 02, 2016 7:40 pm

Hi, I might guess band trouble. Post what you find in the pan. Too bad
B RON CO. Still workin' on it!

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Re: 1968 Mustang C4 Transmission weak into gear

Post #4 by Crosley » Thu Jun 02, 2016 9:40 pm

If the transmission is old. It could be a hard seal on the forward clutch pack. The inner seal can get real hard with age and heat. The forward clutch pack operates in all forward gears. All 3 gears may feel weak.

Since it has a firm reverse, that indicates the main line pressure is good.
Tony in AZ...

"130 mph is known as first gear at the Bonneville Salt Flats"

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Re: 1968 Mustang C4 Transmission weak into gear

Post #5 by OpelGT+3point3 » Thu Jun 02, 2016 10:21 pm

yup sounds like could be shrunken piston seals. Dump a quart of trans-x in it. I have used it many times; even on a C6 that had nothing forward. Those trans have screens. I wouldn't even drop the pan.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #6 by CoupeBoy » Thu Jun 02, 2016 10:40 pm

It is old.
I've been driving this car with this transmission in it for 15 years. The only fluids it has gotten is for topping it off after any transmission work. Like when I changed the radiator or the bell housing and I drained the torque converter. Or it just leaked it out.

The behavior now is just like when it has run low on the past.
The dropping of the pan is more so I could say I did it, and so that when I refill it, it will be @ full, not over full.

Even if I end up pulling the transmission for service; it has served a long life.

This car was driving just fine since March, I just don't drive it often enough to catch things like this when they first occur.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #7 by JackFish » Fri Jun 03, 2016 12:29 pm

Might want to check the vacuum modulator.
Mine was slipping like crazy trying to get into first.
If you pull the hose and fluid starts coming out there's yer problem.
It's a little awkward to get to at the back of the tranny.
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Re: 1968 Mustang C4 Transmission weak into gear

Post #8 by CoupeBoy » Fri Jun 03, 2016 1:19 pm

Now that you mention it...
Early this Spring, I took it out for a drive and on one "spirited acceleration" the car smoked white and stunk of burning ATF.
I didn't get the screen changed last night, other family stuff came up.. Fargo's first downtown cruise night :rolflmao:
IMG_3166.JPG

I'm the white one in the front
IMG_3165.JPG


I'll call around and find a vacuum modulator before I leave town, and hopefuly I'll make time this weekend for maintenance.
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Re: 1968 Mustang C4 Transmission weak into gear

Post #9 by CoupeBoy » Wed Jun 08, 2016 5:29 pm

Proper fluid level and a new vacuum modulator did not change the behavior.
I'm going to try adjusting the bands and see what I can get from that.

I'm also going to have to dig out my C4/C6 rebuild book, I bought one years ago.
O'Reily's has a master rebuild kit for $85 if i need to go that far.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #10 by bubba22349 » Wed Jun 08, 2016 6:42 pm

If you have Justice Brothers products in your area try some of their Transmission Condistioner works great on hard seals. Good luck :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #11 by OpelGT+3point3 » Fri Jun 10, 2016 12:08 pm

Like I said, it's the internal seals.You have to either take the trans apart and replace them or a chemical to expand them. Sure, adjust the bands if you want, but that only works on reverse and second gear. I knew changing the fluid and filter wouldn't do anything. The modulator had an extremely rare odds at working; only if it had the wrong pin or mod in it to begin with. O'Reilley's rebuild kit is like a kit for a carb, not like an engine rebuild kit, which; you know never has everything you really need to do the job right. Transmission overhaul kits don't have the selective washers needed for a C4. The more you slip a trans, the closer you get to rebuild time. It may be too late. Sealer has to be used when the problem first starts, otherwise the clutch packs slip and burn up the fibers. If you decide to rebuild it, I'll answer questions, but sometimes I don't get in here for a few weeks at a time. I rebuilt my first C4 in 1980 or it might have been 1981..I can't count how many since.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #12 by CoupeBoy » Fri Jun 10, 2016 5:00 pm

I'll stop and pick up some Trans-X on the way home, give that a try.
I'm not really a fan of fixing a physical problem with a chemical solution though.
Since I noticed the issue last week, the car has only been driven a couple times and mostly on long drives where the transmission goes into gear and stays there without slipping.
I'm hopeful that there is not permanent damage yet...

I've got a couple C4's, so If I need to rebuild, I'll grab one of those for use or rebuild first; thanks for the offer.

For example there is a C4 on my shop floor out of a 1970 that was behind a running/driving 170, I should be able to swap the bellhousing and swap it in, hopefully it works, if not, I'll work on rebuilding the one that is in there now.
Or sitting at Dad's house there is a 1984 motor/AOD out of a 4dr Crown Victoria that I've been wanting to swap in for a few years now. Dad also has a 1991 Lincoln that I could pilfer the EFI/AOD from.. The motor needs some new lower end bearings.

I know the overdrives have proven themselves over the years, but its kind of nice to have such a simple auto. Its like my own personal Giligans Island
No power steering, no power brakes, no ac (that works), no disk brakes, manual windows, carb.

The most complicated thing on the car now is the radio.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #13 by OpelGT+3point3 » Sat Jun 11, 2016 12:07 am

I have an aversion to it as well because it's usually a broken lathe cut grommet type seal at the outer edge of the forward clutch piston. They get old and brittle from losing their compounds that keep them resilient, then they shrink and become smaller in diameter. That's when they crack. Then the fluid runs thru the crack under pressure and your piston can't apply enough pressure to keep the clutch pack from slipping and burning up; your car stops and everything transmission related becomes contaminated with particles. Look at it as restoring the resilient compounds into the rubber seal. Use V8 drums in your build because they hold more clutches since the retaining ring groove is further up in the drum.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #14 by CoupeBoy » Thu Jun 16, 2016 11:16 am

Last night I dropped the pan again and let the fluid drain.
I put in a jug of Lucas transmission fix. That stuff reminded me of 'engine honey', super thick oil that I had to squeeze the bottle to get it out of.
It ran and drove marginally better. One thing I noticed though when it was hot is that it had s very low frequency chatter, sounded/felt like metal on metal inside a hollow tube.
But only when taking off too quickly or around 60 mph when it downshifted. Manual shifting seemed fine, both up and down.
I still haven't attempted any band adjustments, but based on the sound/feel. It is time for replace/rebuild.
My wife drives a bit like an old lady, so I am hoping it will hold out for a week or 2.
Laying on my back last night wasn't pleasant at all... about a week ago my wife's 3yr old AQHA filly (named Paisley) did some damage to both my wife and myself.
The horse was only saddle broke in April, and this was probably only the 5th ride on her at home. All was going well, the suddenly she started bucking like a rodeo bronc; the horse tossed my wife. My wife ended up with a broken collar bone and a couple cracked ribs. Then when I attempted to unsaddle the horse, somehow Paisley managed to buck into me, lift me off the ground by the saddle horn, cracking at least one of my ribs.
Solid surfaces to lay on are NOT my friend, but its getting better.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #15 by OpelGT+3point3 » Thu Jun 16, 2016 1:08 pm

Lucas is a non-solvent. It's mostly a friction modifier and contains chemicals to help seals somewhat, but is designed to improve traction between the clutches and steels. Like what you would put in a posi. Not really something to restore seals like TransX. If you' smelled both you'd notice a definite solvent smell to the TransX, and it's thin like transmission fluid. Don't bother dropping the pan to install it; just take out the modulator and fluid will come out, especially if it's set overnight. Brake fluid works too, but I'd only use a cup of it.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #16 by CoupeBoy » Thu Jun 16, 2016 1:29 pm

I had the TransX in my hand, and then I made the mistake of asking the guys at the counter what they recommend.
When I changed the vacuum modulator I remember how much poured out.
Looks like another trip to the parts store is in order until I can get a more permanent solution.
Luckily neither cost more than $15

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Re: 1968 Mustang C4 Transmission weak into gear

Post #17 by woodbutcher » Thu Jun 16, 2016 4:02 pm

:D Hi CoupeBoy.Have a C6 in my F150 1984 vintage.Has North of 400k miles on it.However,I change ALL of the fluid every 2 years and adjust the band at the same time.My TC has a drain plug so total change fluid is no problem.
Good luck.Have fun.Be safe.
Leo
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Otto von Bismarck

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Re: 1968 Mustang C4 Transmission weak into gear

Post #18 by OpelGT+3point3 » Thu Jun 16, 2016 7:42 pm

I hardly ever change fluid but always the filter. Sometimes a little additive; 1/4 can TransX. People bring me transmissions to rebuild that have red fluid in them, I save it for my vehicles. But NEVER in a trans with just a screen like a C4 or C6 or FMX. I have adapters to put chrysler dacron mesh filters in C4's; then I'll use used fluid. Sometimes you can find dacron C4, C6 or FMX filters, but rarely; the C4 and C6 ones will clog easy if you have trash in your converter that gets washed out with the new fluid. But if there's much in the converter, the trans is toast anyway.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #19 by CoupeBoy » Wed Jun 22, 2016 2:20 pm

After the Lucas transmission fluid additive, I drove it for the day, the transmission puked fluid on my work parking lot concrete.
Unflapped, I added half a bottle of TransX and topped off the fluid again.
After driving less than 3 miles I got back home and it was slipping just as much as it was before the additives.
Time for a rebuild.
Since I've never rebuilt one and my wife wants it back on the road asap, tonight after work, I'll be pulling out the current transmission, changing over the bellhousing to the other C4 (i6/170 from a 1970 Maverick), and shoving it back in. Then I'll take the car for a test drive, see how well my $25 purchase treats me. And tomorrow I'll drop off the current v8 transmission for rebuild. I am aware that the i6/C4 has fewer clutches, so I'll tell my wife to take it easy for a while.

I called 2 places, both said they could rebuild it in a day to 1.5days, both had comparable prices, one included a new torque converter, the other said they would inspect the trans and replace necessary parts.
Like a Rookie, I forgot to ask about warranty from either source... I must have been tired or sleeping when I made the calls, that's a newb omission.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #20 by OpelGT+3point3 » Wed Jun 22, 2016 2:51 pm

I get a few rebuild jobs that were done by other companies from San Diego to los Angeles; San Bernardino. Most of the time they're still under warranty. When i ask why they don't just bring them back, they say they're tired of taking them out. I don't even give receipts; everything cash. A guy called me about an FMX I did over a year ago; slipping in third. I said take it out and bring it back. He's been street racing with no kickdown. so I said I'd have to charge him something. I have shops bringing me transmissions I'm rebuilding for $350 and they're charging $500 for the R&R. About 900$ with fluid; over a grand with converter. Which is still not too bad for around here, I guess..
Why is your transmission leaking? It's not coming out the top of the dipstick tube from a clogged vent, is it?

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Re: 1968 Mustang C4 Transmission weak into gear

Post #21 by CoupeBoy » Wed Jun 22, 2016 4:42 pm

It isn't coming out of the top of the tube, but that isn't to say the o-ring isn't bad at the bottom of the tube.
The transmission has been leaking randomly for years, but it has never spewed out this quantity of fluid, not even when the front pump seal and pump gasket went bad.
I assume those two went bad because the previous owner ran it without alignment pins between the motor and transmission.

Its been 16 years of use with no real idea how much use it had before I took ownership.

If the 'temp' C4 works, I may try rebuilding this on my own because I'll have more time. But if not, pay I will.

FWIW, one said $595 for rebuild with torque converter. The other said $350 plus parts.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #22 by OpelGT+3point3 » Wed Jun 22, 2016 9:34 pm

I would recommend doing it yourself but only if you do it (your first one) a certain way. Don't remove the little snap ring from the output shaft. Assemble the trans with it standing on it's tail. Grease the thrust washers to hold them in. Don't remove the manual shaft to replace the seal unless it's actually leaking. Don't take the valve body apart. DO take the pump apart to check the bushing, easier to knock out and replace the seal, Be sure to replace both seals in both drums. Grease the four ring grooves on the back of the pump cover so the rings stay centered. Grease the inside of both drums so the rings don't hang up. Place the assembled pump in a vise with the rings and front selective thrust washer installed. Lower the front drum down onto it and air check the clutch pack with a rubber tipped nozzle thru the rear pump holes. Then install the thrust washer onto the back of the front drum and install the forward drum next; wiggling it to engage the direct frictions to the forward drum and air check it. Only takes about 40 pounds. to activate the pistons. Use the band to hold the drums in not too tightly. Put the input shaft into the forward drum to guide the pump in. Throw away the little thrust washer that's tanged to the very rear of the pump cover in front of the forward drum and adjust end play with the front one that's in front of the rings. It has a number on the bottom. You'll need a #3 or #4. Doesn't come in the cheapo kit. Get extra pump gaskets so you can take it back apart to adjust the end play. Don't re-use that gasket. And don't use an old original one to check it. The direct drums wobble and wear out the rings PLUS where they ride inside the drum. Any drum scoring whatsoever REPLACE it. Don't take apart the stuff I said not to...cuz...remember....it probably won't work anyway...The hardest part is installing the pump. You might have it in and out ten times on your first trans. Get good at it cuz that's where most beginners fubar. Oh, and pry behind the sun gear shell to pop out the guts. Don't scratch the thrust washer in there. Don't try to remove the rear band or the rear drum. If reverse works good, don't remove the rear servo cover or change the rear band adjustment. If you follow this advice and don't have tranny parts bouncing all over the floor, you might actually get this thing together and working. Remember; modulator selection and pin length are critical on a C4. If it's off very far, it won't even shift, or shift into third at ten mph.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #23 by CoupeBoy » Fri Jun 24, 2016 12:26 am

It's out
It took about 2 hrs.
Slower than it should be. That includes jacking and blocking, it was done on the floor, using only hand tools, and by myself.
Delays were in the form of the boy asking to have his go cart started, my wife needed something moved, and my daughter started roller blading in my shop. These were minor. The real slow down was my ribs; about two weeks ago I cracked or broke a couple on my left side. My wife's horse (3yr old filly, just saddle broke this spring) is to thank for those. Lying in concrete with those is painful.

Viola!
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Re: 1968 Mustang C4 Transmission weak into gear

Post #24 by OpelGT+3point3 » Fri Jun 24, 2016 10:59 am

I do a lot of bench jobs and two hours is kinda quick from what I hear. You should drop it with the converter. The splines can get chewed up otherwise. You could take it apart real quick and see if it's just the forward clutch; replace that and slap it back together..I've seen a lot of guys go all out on their first rebuild just to end up having it not work at all because they tried to do too much too soon.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #25 by CoupeBoy » Fri Jun 24, 2016 11:20 am

OpelGT+3point3 wrote:I do a lot of bench jobs and two hours is kinda quick from what I hear.
I'm certain that if I had less of a mess in my shop and had use a floor jack instead of a transmission jack, and used some power tools, that I could have had it out in just over an hour.
OpelGT+3point3 wrote:You should drop it with the converter. The splines can get chewed up otherwise.
The torque converter was in the transmission until I got it onto the ground, then I slid it out the front.
OpelGT+3point3 wrote:You could take it apart real quick and see if it's just the forward clutch; replace that and slap it back together..I've seen a lot of guys go all out on their first rebuild just to end up having it not work at all because they tried to do too much too soon.
I appreciate the comments and encouragement, however in this instance, time is not on my side. If I were going to rebuild it myself, I should have already ordered the parts and had them at home, I have not. If I ordered them today I would at best get them Monday. And my shop is a mess, no suitable place to work on it. And Wednesday I *might* be taking off for Montana for a few days, no time.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #26 by OpelGT+3point3 » Fri Jun 24, 2016 12:26 pm

But you don't know what parts you're going to need. At least take the pump out and check the clutches in the front drum and the forward clutch drum. If you begin familiarizing yourself with the parts then eventual success is more probable. Post pics of the clutches.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #27 by CoupeBoy » Fri Jun 24, 2016 12:34 pm

Having been on the receiving end of somebody who tried to do it themselves (I was an ASE certified mechanic -- electrical, suspension, brakes) I've been hesitant to crack it open, because I always hated getting half done (usually incorrect) projects from customers, or losing some 'non-wear' part that is made from unobtainium.

And we ALWAYS charged them more
Times have changed, but we used to have a sliding scale for hourly rate.
$25/hr
$35/hr if you watch
$45/hr if you tell me how to do it
$80/hr if you "fixed it" before bringing it in

I'll be asking for all parts back to perform a postmortem, and I'll be asking for them during the drop off so they have no excuse for 'throwing them away'.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #28 by OpelGT+3point3 » Fri Jun 24, 2016 12:37 pm

There could be unusable hard parts in there and it could have 6 cyl drums. You have no way of knowing. Buying parts before you know what you need is a step in the wrong direction.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #29 by OpelGT+3point3 » Fri Jun 24, 2016 12:39 pm

Oh okay, I thought you were going to work on it yourself.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #30 by CoupeBoy » Fri Jun 24, 2016 1:16 pm

Unfortunately not this this go around, just not enough time.
This is the car my wife drives most of the summer and she wants it back on the road ASAP.
I presented options and costs, she chose.

If it were one of my normal projects, I'd sideline it and learn/do it myself.

next time..

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Re: 1968 Mustang C4 Transmission weak into gear

Post #31 by OpelGT+3point3 » Fri Jun 24, 2016 3:32 pm

If that 6 cyl trans fails then you know it's all your fault..been there done that, haha. At least you know your present trans could get by with a forward clutch. Fingers crossed for ya tho.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #32 by CoupeBoy » Fri Jun 24, 2016 3:50 pm

This will be the first time I've ever paid to have a transmission rebuilt. And with a little luck, it will be the last.
My fingers are crossed.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #33 by OpelGT+3point3 » Sat Jun 25, 2016 8:18 pm

Changing out the forward clutch is about like replacing a carburetor. And it's always good to work with a known problem.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #34 by CoupeBoy » Wed Jul 13, 2016 10:55 am

I picked up the transmission Monday and installed it last night.
No leaks, and I only lost 1 'oh jesus' clip; the one that holds the kickdown cable to the transmission.
I took it for a test drive, even without it hooked up.
I manually shifted 1st, 2nd, 3rd
I let it automatically shift, I put it in drive and it shifted 1st, 2nd...

Heres the part that sucks.. no 3rd. Even though I manually put it in 3rd and I started out in drive, it would not shift past 2nd.

Last night the internet said that I needed to adjust the vacuum modulator with an internal screw and/or check that the push rod was installed correctly, and to ensure there is proper/adequate vacuum at the modulator.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #35 by OpelGT+3point3 » Wed Jul 13, 2016 12:07 pm

If it shifts to second on its own; with the lever in drive, the problem is internal. Next; if reverse isn't delayed, then it's probably valve body. See, that's why I suggested working with the original. It shifted. Now you have a new set of problems; plus time wasted relying on some "expert" rebuilder.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #36 by CoupeBoy » Wed Jul 13, 2016 12:38 pm

It was late when I went for my test drive (11:30pm) but I am 'pretty sure' that when I put in drive, it will shifted from 1st to 2nd.
Of course, I was also manually shifting when half asleep, so I will have to re-verify the testing later.
When shifting from forward to reverse, it engages immediately, I know this for certain.

The time wasted thing burns me just a little bit.
He said 3 days, and it took him almost 3 weeks, granted I did tell him that if he couldn't have it done by Wednesday (june 30) that I would be out of town for the next week and a half, so he may chose to take his sweet time.
But that doesn't explain why he would wait until the Thursday before I got back to call and re-verify the year/engine before he ordered a torque converter, which he said would arrive last Thursday or Friday, but I didn't get a call back until this week Monday. FWIW, this rebuilder was not recommended by any of the local Mustang club members (they didn't warn against this shop either). Their overwhelming recommendation was for a shop/guy who was booked out for the next 3 months.

I know better for 'next time'

OpelGT+3point3
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Re: 1968 Mustang C4 Transmission weak into gear

Post #37 by OpelGT+3point3 » Wed Jul 13, 2016 12:51 pm

I had a bad feeling about it from the getgo and I think I have a lot more confidence in your mechanical abilities than you do. Of course, I know exactly what's involved; you would be delving into the unknown, From what things you had already worked on, I figured that to replace a forward clutch would be do-able in a few hours and you could be back on the road.

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CoupeBoy
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Re: 1968 Mustang C4 Transmission weak into gear

Post #38 by CoupeBoy » Wed Jul 13, 2016 1:59 pm

OpelGT+3point3 wrote:I had a bad feeling about it from the getgo and I think I have a lot more confidence in your mechanical abilities than you do.
I'm not concerned about my skills, to pay for college I was an ASE certified mechanic, Brakes/Electrical/Suspension. It really wasn't about being uncomfortable, I was paying for (expected) expedience and experience to get my wife back on the road ASAP. Plus right now my shop is a complete and utter mess, I was concerned that I'd lose more than one clip, spring, or check ball. There isn't a single horizontal surface that is clutter free. Years ago I bought a C4/C6 rebuild, I can't say that I've read it thoroughly, but I have replaced the front pump on this trans once, when the O-ring failed, and the front seal.
OpelGT+3point3 wrote:Of course, I know exactly what's involved; you would be delving into the unknown, From what things you had already worked on, I figured that to replace a forward clutch would be do-able in a few hours and you could be back on the road.
It is only semi-unknown, I've rebuilt motorcycle clutch systems in the past, both manual/semi-manual and the automatic/centrifugal type used by snowmobiles and Honda Odysseys. Numerous automotive manual clutches.

I hoped that I could pass off the rebuild and it would let me focus on my other projects, namely I had to build a chicken coop before we took out 1.5week vacation trip to Montana..

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Re: 1968 Mustang C4 Transmission weak into gear

Post #39 by OpelGT+3point3 » Wed Jul 13, 2016 2:20 pm

If you replaced a pump, the forward drum is two more minutes to remove; and that's only because you have to remove the band struts; otherwise 2 seconds. And the valve body didn't even need disassembled just unbolted from the case and reinstalled. The only clip was the one holding the clutches in, and you could have air checked the pistons seals pretty easy. Even if the seals needed replaced, the forward piston return spring is just a dish and it isn't under any pressure like the direct one is. I just hated to see you go to all that trouble when it was an easy fix. And now shifting problems..yikes.

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Re: 1968 Mustang C4 Transmission weak into gear

Post #40 by CoupeBoy » Thu Jul 14, 2016 9:58 am

It was the vacuum hose at the vacuum modulator.
It was disconnected; I don't know how or why.
I replaced it with new hose and it works through all 3 gears now.
When up shifting (holding the pedal to the floor) it is running higher rpm before shifting, hopefully that is something simple.

OpelGT+3point3
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Re: 1968 Mustang C4 Transmission weak into gear

Post #41 by OpelGT+3point3 » Thu Jul 14, 2016 4:09 pm

Oh...you had posted that it automatically shifted into 2, so that meant you had vacuum to the modulator. But I guess you meant to post that you shifted it MANUALLY into second. You could put a washer under the mod to make it shift sooner. If you come out too far, it will rev up between 2 and 3.

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