Driveshaft question 78 4x4 longbed

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TeamNeptune
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Driveshaft question 78 4x4 longbed

Post #1 by TeamNeptune » Tue Oct 09, 2018 5:37 pm

I have a 1978 f150 Ranger 4x4 long bed with a 300 six I have been working on. It has a 4" lift with 35" tires. Originally it had a 3.50 gear. I mainly use it to pull my boat hear from the Charlottesville va area mostly east. My boat is around 2000lbs and the truck would struggle to keep up speed on some hills. So I decided to go with a set of 4.11's to bring the gearing back closer to stock. I drove the truck for the first time on the highway with the 4.11's and it ran really well up to about 65mph after 65 it would start getting a vibration which was worse if I coasted at that speed. one driveshaft place told me it had reached critical rpm but its hard for me to believe that Ford would build a truck that couldn't safely go 70mph. I am in the 2700 rpm range at 70mph..

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Re: Driveshaft question 78 4x4 longbed

Post #2 by wsa111 » Wed Oct 10, 2018 3:16 pm

First check u-joints for play.
Balance driveshaft.
Make sure the trans output shaft is parallel to the angle of the pinion shaft u-joint flange.
Best of luck.
67 mustang,C-4, with mod. 80 hd, custom 500 cfm carb with annular boosters, hooker headers, dual exh.-X pipe, flowmaster mufflers, HEI dist. Engine 205" .030" over with offset ground crank & 1.65 roller rockers. 9.5 comp., Isky 262 cam.
2003 Ford Lightning daily driver. Recurving Distributors. billythedistributorman@live.com
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Re: Driveshaft question 78 4x4 longbed

Post #3 by TeamNeptune » Thu Oct 11, 2018 5:37 am

Yes thanks. I have some new slipjoint yolks and u-joints on the way. I wasn't sure if I should be considering a larger diameter shaft. I decided to go ahead and repair what I have and see. Hopefully the male spline is not too worn.

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Re: Driveshaft question 78 4x4 longbed

Post #4 by wsa111 » Thu Oct 11, 2018 9:52 am

Check the driveshaft for runout.
Make sure the bushing in the trans extension housing is not worn.
Get the shaft balanced.
67 mustang,C-4, with mod. 80 hd, custom 500 cfm carb with annular boosters, hooker headers, dual exh.-X pipe, flowmaster mufflers, HEI dist. Engine 205" .030" over with offset ground crank & 1.65 roller rockers. 9.5 comp., Isky 262 cam.
2003 Ford Lightning daily driver. Recurving Distributors. billythedistributorman@live.com
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Re: Driveshaft question 78 4x4 longbed

Post #5 by TeamNeptune » Thu Oct 11, 2018 7:44 pm

The shaft comes out at the transfer case. I could not feel any play or movement in that yolk.
I will take it to be balanced after installing the new yolk and new u joints.
Looks like I won't get the parts until the middle of next week but I will post back with my results.
Until then I guess I should get started on getting these 4.11 gears in the front dana 44.
I am trying to decide if I should get a case spreader or not. I have set up several 9" gears but this will be my first dana 44.

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Re: Driveshaft question 78 4x4 longbed

Post #6 by TeamNeptune » Thu Oct 11, 2018 7:51 pm

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Re: Driveshaft question 78 4x4 longbed

Post #7 by bubba22349 » Fri Oct 12, 2018 8:18 am

:hmmm: Have you checked the condition of the driveshafts center support bearing? A worn out or damaged one is a common cause of driveshaft vibration. Good luck :thumbup: :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: Driveshaft question 78 4x4 longbed

Post #8 by B RON CO » Sun Oct 14, 2018 8:46 am

Hi, one of my tricks is to put the truck up on stands and run it in gear. Often you will see what is causing the vibration. Be very careful supporting the truck and when you crawl underneath.
Besides that, as mentioned, the driveshaft angle is different with the lift. If it too severe there are shims for under the spring pads to point the yoke more at the transfer case.
Good luck
B RON CO. Still workin' on it!

1933 Ford Pickup - 59A Flathead V8
1966 Ford Bronco - U14 - 170/200 Straight 6
1966 Ford Mustang - 289 V8

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Re: Driveshaft question 78 4x4 longbed

Post #9 by wsa111 » Tue Oct 16, 2018 4:25 pm

If has a two piece driveshaft. Make sure the u-joints are in phase from the front shaft & rear shaft.
67 mustang,C-4, with mod. 80 hd, custom 500 cfm carb with annular boosters, hooker headers, dual exh.-X pipe, flowmaster mufflers, HEI dist. Engine 205" .030" over with offset ground crank & 1.65 roller rockers. 9.5 comp., Isky 262 cam.
2003 Ford Lightning daily driver. Recurving Distributors. billythedistributorman@live.com
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Re: Driveshaft question 78 4x4 longbed

Post #10 by TeamNeptune » Wed Oct 17, 2018 5:05 am

It has a 1 piece driveshaft I think I measured it at 72". That is why one shop was telling me at 2600 rpm it had reached its critical rpm and would start to bow and shake if spun any faster. I get the new yolk for it today but I won't have time to do much until this weekend. I still need to get the front diff. together. The old 3.50 pinion measured the same as the new 4.11 for thickness (it was within .005). I am hoping just transferring the old shims over will give the new one the right depth . I am not sure the math and the factory pinion depth seemed about .030 off . That seems like a lot from just wear.

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Re: Driveshaft question 78 4x4 longbed

Post #11 by bubba22349 » Sun Oct 21, 2018 10:59 pm

Have you checked the pinion and drive shaft angles are within specs? :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: Driveshaft question 78 4x4 longbed

Post #12 by TeamNeptune » Tue Oct 30, 2018 6:07 pm

I finally got the right carrier and the Dana 44 back together this past weekend. The new slip yolk on the back driveshaft has taken care of the vibration problem. All is looking good at this point. The front drive shaft has got some play so I may try a new yolk on it before sending it off . The 4.11 gears with the 35" tires seems like a good match at least for this area and for what I am using the truck for.
JD

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Re: Driveshaft question 78 4x4 longbed

Post #13 by sdiesel » Mon Nov 26, 2018 10:56 pm

often times when u replace slip yoke, u are replacing only 50 % of the problem.
the yoke and splined stub wear together.
the new yoke reduces that wear clearance, but will wear rapidly against the old stub.
absolute proper repair is to replace them both as a unit.
if doing that, order up larger dia. tube 4" or greater for 72"
u likely have 3.5 which is really pushing it for 72".
a long love affair with the 300 six.
my lastest and final fling is a fresh 300 in an 88 ford f350 dually 4X flatbed

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Re: Driveshaft question 78 4x4 longbed

Post #14 by TeamNeptune » Sat Dec 01, 2018 12:02 pm

Yeah I am still getting some vibration when decelerating and at high speed. The new yoke helped but I am still not happy with it.. Lifting the truck 4" has moved the yoke 1" further out on the spline and I think this could also be contributing to the problem as well. I was hoping that I could find a yolk 1' longer to help. Looks Like it could be 1"1/2 longer and still have plenty of room for travel.. I could still see some of the coating on the spline and I thought It wasn't worn nearly as bad as the yoke. I was told that they are made from different metals and that they do not wear at the same rate. I may have to save up if a new 4" shaft is in order and yes this one is 3 1/2"..

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Re: Driveshaft question 78 4x4 longbed

Post #15 by sdiesel » Sat Dec 01, 2018 10:59 pm

Likely your too short. especially for that span.

ask u this , I don't wanna read back thru.
did u check you face angles of the pinion yoke and the t case yoke thst they are the same??
or more accurately that they align with each other so the u joint sees the same values st either end of the drive shaft?
a long love affair with the 300 six.
my lastest and final fling is a fresh 300 in an 88 ford f350 dually 4X flatbed

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Re: Driveshaft question 78 4x4 longbed

Post #16 by sdiesel » Sat Dec 01, 2018 11:13 pm

there are a ton of references on line but
driveline nw .com makes it very simple. so does the Spicer site whice driveline essentially copied
a long love affair with the 300 six.
my lastest and final fling is a fresh 300 in an 88 ford f350 dually 4X flatbed

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Re: Driveshaft question 78 4x4 longbed

Post #17 by TeamNeptune » Sun Dec 02, 2018 3:39 pm

No I have not checked the angles. I will have to read up on it to learn how to properly check it. I don't see how the transfer case angle would have changed since it didn't move and It didn't seem that the lift changed the angle of the rear end. what I did to lift the rear was add an extra leaf then add a 2" block. I will try and figure it out.
Thanks JD

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Re: Driveshaft question 78 4x4 longbed

Post #18 by bubba22349 » Sun Dec 02, 2018 4:41 pm

TeamNeptune wrote:No I have not checked the angles. I will have to read up on it to learn how to properly check it. I don't see how the transfer case angle would have changed since it didn't move and It didn't seem that the lift changed the angle of the rear end. what I did to lift the rear was add an extra leaf then add a 2" block. I will try and figure it out.
Thanks JD


:hmmm: I brought up checking your driveline angles in above post #11, :shock: yes of corse the angles have changed from factory stock! They moved just from lifting the height of the truck, even though the transfer case angle or the pion angle didn't change the drive line did. Good luck :thumbup: :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: Driveshaft question 78 4x4 longbed

Post #19 by sdiesel » Thu Dec 06, 2018 12:05 am

Bubba is smack on with this.
go to the referenced site.
rebuild your drive train on paper then go do it.
u must have 3 degrees of angle on the faces and they must be parallel to each other.
few things will ruin a truck or kill people easier than poorly engineered drivetrain.
a well built system will inspire a deep seated satisfaction.
a long love affair with the 300 six.
my lastest and final fling is a fresh 300 in an 88 ford f350 dually 4X flatbed

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Re: Driveshaft question 78 4x4 longbed

Post #20 by TeamNeptune » Thu Dec 06, 2018 5:11 am

I have a Protractor on order. I should have it next week by the 10th-14th. I will post back when I get the results.
Thanks JD

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Re: Driveshaft question 78 4x4 longbed

Post #21 by TeamNeptune » Sat Dec 08, 2018 12:23 pm

I was able to download a free protractor app onto my iPhone.. I am still going to double check it when the one I ordered on line comes in.. Yes this drive line needs help !! (I will remove the driveshaft later this weekend). The measurements I got today I used a socket sitting on the cap of the u joint. Yoke from transfer case 3.5* down. driveshaft 11.0* down. pinion yoke 9.6* down. First operating angle is 7.5* and the second operating angle is 1.4*.. I am not really sure where to go with this. I am thinking that the angle of the t-case needs to go down another 5*..

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Re: Driveshaft question 78 4x4 longbed

Post #22 by bubba22349 » Sat Dec 08, 2018 1:11 pm

For best u joint life and vibration control you would want 3 degrees or less. Good luck :thumbup: :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: Driveshaft question 78 4x4 longbed

Post #23 by TeamNeptune » Sat Dec 08, 2018 6:05 pm

I have not been able to find any information about changing the transfer case angle. Do you know anyone who has done this. ?

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Re: Driveshaft question 78 4x4 longbed

Post #24 by bubba22349 » Sat Dec 08, 2018 6:27 pm

:hmmm: Some pictures would be helpful in this. I haven't done specifically a transfer case or know of anyone that changed the transfer case angle my best best guess is you would need to rebuild its mounting location height to be able to drop it so as to change its operating angle. I will usually start at the axle first though and change its piñon angle either by using some degreed wedges or in extreme cases cutting the mounting pads loose and repositioning the pinion height then rewelding them. Good luck :thumbup: :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: Driveshaft question 78 4x4 longbed

Post #25 by TeamNeptune » Sat Dec 08, 2018 6:52 pm

I am thinking that increasing the pinion angle will help offset the vibration of the differential angle. I know it will not be optimal for the longevity of the u-joints but it should help offset the vibration. I will be in touch with skjkr and checking other forums this coming week as I know I am not the only redneck to put a 4" lift on a ford truck and I am planning on keeping it for the rest of my days. Thanks for the help. JD

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Re: Driveshaft question 78 4x4 longbed

Post #26 by TeamNeptune » Sun Dec 09, 2018 8:31 am

What I have been able to find out is by dividing the length of the driveshaft by 5 you can find the maximum angle of the driveshaft for a single cardan joint. Last I checked my driveshaft was at 11 deg. My 72 " driveshaft should allow for 14.4 deg. of angle. The operating angle will be 7.6 which is twice the optimum of 4*. This increased angle will cut the longevity of the u-joint in half. A double cardan shaft would be a better solution but for now I am going with shims over the leaf spring mounts to correct the pinion angle. The cause of the vibration is most certainly caused by the operating angles on each end of the driveshaft being out of phase. With my transfer case angled down 3.5* my pinion angle should be angled up the same or even 1* less to allow for movement from torque. I will also be hooking the boat up to the truck to see how this affects the geometry and taking this in to consideration. I want to thank bubba,wsa, and sdiesal for helping to steer me in the right direction. I know that there are those that would ask why go through all this to lift a truck, and I will just say if you have to ask you just wouldn't understand.. Thanks JD

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