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1973 F100 "C" code 3 speed, what is it?

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Jesse73
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1973 F100 "C" code 3 speed, what is it?

Post #1 by Jesse73 » Tue Mar 26, 2019 6:00 pm

Hey guys,

I need to make some gearing decisions soon for my F100 and I'm hoping you could shed some light on what I have.

My door code says transmission "C". So far all I can find is that this means "3 speed"

I would like to know what I have and if I can find an overdrive to add to it (replacing tail housing with overdrive unit) Is this a ford toploader 3.03?

For now I would like to keep the 3 speed on the column. I would like to figure out what to do before I try and find a new rear center section. Pinion seal is leaking badly, but a prior owner has welded the ujoint holder-thingy to the pinion nut/shaft so the center section has to come out for repair or replacement. Now would be the time to change ratios if I so choose.

I can't decide if I should stick with this 3 speed and change my rear axle ratio, add an overdrive and stay with the stock 3.73 ratio, or find a different transmission all together. Or change ratio and add an overdrive.

Goals are to cruise at 65-70 and maintain 2,000 rpm, and haul a 3,500# trailer at 60-65 mph without revving to the moon out of overdrive.

Thanks!

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bubba22349
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Re: 1973 F100 "C" code 3 speed, what is it?

Post #2 by bubba22349 » Tue Mar 26, 2019 6:09 pm

Yes the trans is a 3.03 top loader 3 speed. :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.

Lazy JW
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Re: 1973 F100 "C" code 3 speed, what is it?

Post #3 by Lazy JW » Wed Mar 27, 2019 3:50 pm

Jesse73 wrote:...

Goals are to cruise at 65-70 and maintain 2,000 rpm, and haul a 3,500# trailer at 60-65 mph without revving to the moon out of overdrive.

Thanks!


My 81 F-150 has 2.75 gears w/T18 granny tranny. It would probably pull that load in 4th (direct) at 60ish/2000 on level ground with no wind at 2000 rpm, but add ANY headwind or hill and it's gonna slow down quickly.

That is a pretty tall top ratio for that load; I strongly recommend gearing for about 2500-2700 at 60 mph in direct with some sort of overdrive for cruising empty.
"The White OX" 1974 F-350 300-6, Stock single exhaust, Carter YF, T-18A, Dana70 w/4.11, Flatbed dually w/dump bed. "Where no oxen are, the crib is clean, but much increase is by the strength of the ox" (Proverbs 14:4)
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Jesse73
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Re: 1973 F100 "C" code 3 speed, what is it?

Post #4 by Jesse73 » Thu Mar 28, 2019 10:38 pm

Lazy JW wrote:
My 81 F-150 has 2.75 gears w/T18 granny tranny. It would probably pull that load in 4th (direct) at 60ish/2000 on level ground with no wind at 2000 rpm, but add ANY headwind or hill and it's gonna slow down quickly.

That is a pretty tall top ratio for that load; I strongly recommend gearing for about 2500-2700 at 60 mph in direct with some sort of overdrive for cruising empty.



Right, that's the issue I'm working on mulling over. I'm hoping I can pull a trailer in 3rd at 1:1, but as I sit now if I have to drop out of 3rd down to 2nd to clear a hill I'm running at 2800 rpm and 40 miles an hour. Not ideal on the highways unfortunately.

If I could find a 30% overdrive that held up I could hit 2nd overdrive and run 55-at 2800 rpm. That would actually be pretty close to my target speeds and rpm if I could make that work. I think my engine will pull a decent hill if I could more effectively keep it in the power band.


Switching my 3 speed for a 4 speed and setting it up on the column wouldn't really help that much. It would give a tighter ratio but probably worse 1st gear and the same 1:1. Plus the reverse would be a seperate handle.

Switching to a top shifted 4 speed like a T18 is sort of a no-go for me, I like the column shift for now. If I switch to floor shift it will be to a 5 speed I think.


I am sort of rambling here. I think I have convinced myself to stick with the 3 speed and 3.73 rear end. I have been using these two sites to calculate speeds and ratios.


https://www.gearvendors.com/hrfordratios.html


This site is for easy jeep calculations but you can type ratios in the final column by hand and it shows speed and RPM. A little easier than writing out the math for each ratio change.

http://www.public.asu.edu/~grover/willys/speed.html


As an aside I have found out there seems to be no overdrive that bolts onto the ford 3.03. I was hoping a Borg Warner r11 would fit but I think no.


Now to find a replacement center section and 3.73 gears!

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bubba22349
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Re: 1973 F100 "C" code 3 speed, what is it?

Post #5 by bubba22349 » Sat Mar 30, 2019 1:56 pm

Yes there was a 3.03 with the R11 overdrive unit made, I had one up until a few years ago. They aren't so easy to find now days but it's a great combo having the best 3 speed with all sincrows gears mated to one of the best O D units ever made the R11. If you can locate one it will be about the best you can do with keeping the colum shift linkage. God 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: 1973 F100 "C" code 3 speed, what is it?

Post #6 by Jesse73 » Sun Mar 31, 2019 9:55 pm

Did they make one hooked to an R11? I haven't been able to find reference to that so far. A friend might have some R10 or R11s that we brought him a few years ago, he turned at least one into a divorced unit for his '30s Buick. Would an R11 hold up to towing in 2nd gear? Normally towing in overdrive is a no-no.

Thanks for the thoughts so far folks I really appreciate it!

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Re: 1973 F100 "C" code 3 speed, what is it?

Post #7 by bubba22349 » Mon Apr 01, 2019 10:40 am

The R11 is the strongest OD unit you can get.i wouldn't use a R 10 for towing they are quite weak compared to an R11. The R10 in my opinion should only be used in a stock 1930, early 1940,s, or 1954 or older car / pickup they are also usually only used in the six volts electrical systems too. 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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bubba22349
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Re: 1973 F100 "C" code 3 speed, what is it?

Post #8 by bubba22349 » Mon Apr 01, 2019 5:23 pm

Jesse73 wrote:Did they make one hooked to an R11? I haven't been able to find reference to that so far. A friend might have some R10 or R11s that we brought him a few years ago, he turned at least one into a divorced unit for his '30s Buick. Would an R11 hold up to towing in 2nd gear? Normally towing in overdrive is a no-no.

Thanks for the thoughts so far folks I really appreciate it!


Yes you could tow with the R11 OD unit they are very strong! They had the R-11 option still available in the F100 pickups into the late 1960' early 1970's (the Bump side pick ups) don'tmber exactly the last year they were made. They were also used behind some of the Hi Performance Ford big block V8's before the four speeds were made. I think the first year they made the heavy duty R11 was 1956 to use in the Thunderbird behind the 292 and 312 V8's. During the mid 1970's they were being custom adapted behind big block performance cars with four speeds and automatic's (just like your friend did on his Buick) in many brands to get better gas milage. If you can find one I can show you how to wire it up so you can split shift the gears which would work even better for towing. 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.

Jesse73
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Re: 1973 F100 "C" code 3 speed, what is it?

Post #9 by Jesse73 » Wed Apr 10, 2019 10:11 am

Would you have any ideas exactly what bolts to what? Are there any spline count differences to worry about in this situation? I suppose if all else fails I could turn a BW overdrive into a divorced unit.

Thanks!

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Re: 1973 F100 "C" code 3 speed, what is it?

Post #10 by bubba22349 » Wed Apr 10, 2019 9:02 pm

Ideally it would be easiest to get one of the Ford pickup T85N with OverDrive transmissions this would be almost a direct bolt into your pickup plus some minor drive shaft Mod's and maybe also some work on the crossmember mount. The last year they were available was 1972 in F100 and F250's as well as early as 1952 used behind the 292, 352, 360, and 390 V8's plus the 215, 223, 262, 240, & 300 inline six'es. As far as what bolts the what he R11 units were used in many other brands of car and trucks and car units can be converted to truck use units with the right parts. The R11's are a .72 OD ratio unit that bolts up to an Borg Warner T85N three speed gear case with its adapter plate the three speed gears are the same as a regular Borg Warner three speed trans. Below is a link to a Packard trans repair manual that shows how they fit together and also a Borg Warner OD Manual that describe how they work and shows its details. If you have the ablitys to do machine work they could be adapted to most any trans. Good luck :thumbup: :nod:

Packard OD repair manual
http://www.packardinfo.com/xoops/html/d ... ion_VI.pdf

The Borg Warner Overdrive Manual
http://www.packardinfo.com/xoops/html/d ... /BW_OD.pdf
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.

Jesse73
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Re: 1973 F100 "C" code 3 speed, what is it?

Post #11 by Jesse73 » Wed Apr 10, 2019 9:26 pm

Interesting. A quick scan of eBay shows a few T85 transmission/overdrive combos to be about $1500-$1600. Ruh Roh. Guess I'll have to start looking a little harder.


Funny enough, my Dad still owns my Grandfathers '51 Packard. I don't remember if it has an R10 or R11 overdrive. I don't dare borrow that overdrive :wink:

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Re: 1973 F100 "C" code 3 speed, what is it?

Post #12 by bubba22349 » Thu Apr 11, 2019 6:46 pm

Yeah your dad probably wouldn't go for you borrowing the one out of the Packard. The big cars like Packards, Lincoln's, and trucks usally had the R11's? Maybe you better check with your friend to see if he's got an R11 left from what you brought him. I used to also have a friend that rebuilt all those old three speeds and the OD units too but lost touch with him and haven't seen him in many years. 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.

Jesse73
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Joined: Thu Feb 28, 2019 7:13 pm

Re: 1973 F100 "C" code 3 speed, what is it?

Post #13 by Jesse73 » Thu Apr 11, 2019 11:20 pm

Yes, the overdrive would be missed in the Packard indeed.

I'm still not sure what my friend Pete has in his stockpile. I have my fingers crossed that it's something good. We went to the "Ford Farm" which I believe used to be near Hastings Minnesota and picked up 3 or 4 overdrives for his project. But this was probably 15 years ago now. Could be anything but I'm guessing they were just a good old BW overdrive.

Pete Suick is the owner of Suick fishing lures if you are into musky fishing at all. They also make stuff like Cisco kid and a few others.

We'll have to see if I hit the jackpot on something I bought 15 years ago!

Thanks again,

-Jesse

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