If it were me. I would look in a junkyard to see if you could find a truck like yours (can design and bed length)to pull everything you will need. That way there's no guess work involved.

 

While in general that's true (and is certainly true of the 5 speed overdrives that Ford called "M5OD" in the '90s), Ford did use a light duty trans with 4 forward gears in the '80s that is almost always called a 3 speed with overdrive. So although it's confusing, Peter isn't necessarily wrong.

To add to the confusion, a lot of the "4 speeds" in the '70s and '80s had gear shifts marked "L-1-2-3". And if I recall correctly, the "6 speed" in my '08 F-250 shift **** was marked "L-1-2-3-4-OD". And the "5 speed" automatic in my 2015 E-450 motorhome has 6 forward gears, but 4th is 1.00:1 and 5th is 1.09:1, so it skips 4th most of the time, except when it's cold and it skips 5th instead.

So while it would be a lot more straightforward to say that the number of speeds in a trans name is the number of forward gears it has, that's not strictly true.

 

Most people end up having their driveshaft lengthened/shortened as necessary. In order to find a replacement in a junkyard, you would need to find a truck with a matching engine, transmission, cab, transfer case, bed, and axles. That alone is very tough to do. What makes it worse is that most junkyard move vehicles around with forklifts, which usually destroys the driveshafts.

*Who* almost always calls it a 3 speed with overdrive? People here on the forums? People you know who talk about trucks? Those people use incorrect terminology all the time. Just because it's commonly said doesn't mean it's correct. Now, if you were to show me some Ford literature that refers to a transmission with four forward gears a 3-speed-anything, then you'd have something that you could convince me with.

That's not confusing. It's a four speed.

That's because it has 6 forward gears. It's a 6 speed.

I would like to see where Ford refers to the 6R140 as a "5 speed". The perception is that more gears are better, so if Ford is selling a transmission with 6 forward gears, you can bet money they aren't going to downgrade it by calling it a 5 speed.

I agree that people use the wrong terminology all the time. I don't agree that manufacturers do the same. At least, I've never seen it. From a marketing perspective, as I said earlier, it makes absolutely no sense.

 

I'll accept the correction on this. I've heard the SROD called a "3 speed with overdrive" (as opposed to a "3 speed overdrive") on the '80 - '86 forum a lot. But when I checked in some old Ford literature I only see it called a "4 speed overdrive." So I'll agree that the correct nomenclature, even for the SROD, is "4 speed overdrive"

I agree it's a 4 speed, but I've also heard people call it a 3 speed with a granny low. So it does add to the confusion.

I agree it's a 6 speed and I've never called it anything else. But again, I think it would be less confusing if it were marked "1-2-3-4-5-6".

I don't know about the 6R140, but I'm pretty sure that my E-450 has a 5R110W, and on page 104 of my owners manual it calls it a 5 speed. But what it really is is a 3 speed backed up by a built in 2 speed overdrive. 3 x 2 gives it a total of 6 forward gears. But "2nd gear" in the 3 speed times the overdrive is 1.09:1 which is so close to "3rd gear" (1:1) that it doesn't make sense to go through both gears. Since they aren't using 6 gears Ford does "downgrade" it by calling it a 5 speed.

And to add more confusion, the shifter on my E-450 has "P-R-N-D-3-2-1", so the shifter makes it look like it's a 4 speed, even though it's really a 5 speed that has 6 forward gears!

 

My 87 had the same transmission and I swapped to a ZF several years ago (thread here).

There is some misinformation posted in this thread. The original transmission is a TOD, top mounted shifter with overdrive, and is a similar design to the old toploaders, SRODs, etc, and was used through '87. Chances of finding another one in a junkyard are probably slim to none. I've also seen it referred to as a Tremec T170. Is your truck 4x4? My truck is a 4x2, so your swap may be slightly different than mine.

I re-used the original clutch - both the ZF and the original 4-speed used a standard 10-spline Ford clutch. The tunnel cover in the floor had to be changed to allow clearance for the rear of the ZF, but maybe 4x4s are different. The taller cover stretches the carpet funny, so one of these days I'd like to replace the carpet. I re-used the original clutch master cylinder, but replaced the line and installed a new concentric slave cylinder on the ZF. My truck came with a two-piece driveshaft, but the front half required a different length to line up with the ZF yoke. I bought a driveshaft out of an F250 with a ZF, but the rear half was about 3" too short because it was setup for the 10.25" axle, so I ended up getting the new one re-tubed to match the length of the original rear half. I don't know how the 4x4 version compares, either in terms of overall length or driveshaft configuration. I also had to replace the transmission crossmember and support brackets. You will need one for a 5-speed, with the same engine class (300/302/351 all stamped together), and drive configuration (2 or 4wd) from any 87-96 truck.

I think I have pictures of the swap in my gallery if you want to take a look.

 

You're right about the spline shafts being the same, but there is some difference between a clutch kit for a 4 speed vs one for a 5 speed. Every website I've looked at shows different part numbers for the clutch kits of each manufacturer for a 1988 F-250 351w. I'm not sure what that difference is though!

 

Just out of curiosity....what is the transmission code on the "B" pillar for the OEM trans?

 

IIRC "B" is the code for the Clark 4 speed OD transmission but there has never been any real clarity or definitive information as to the different names for this transmission that I've ever seen. I've heard/seen SROD, TOD, Clark 4 speed, and a few other names I can't even remember. I haven't ever been able to figure how many transmissions there were, what their official names are, their specs, what they were used in, etc. All I know is that there is at least one, and possibly as many as 3 or 4, 4 speed OD transmissions used from about 1980 to about 1987.

 

My4Fordtrucks, the transmission code on my truck is "B".

Andy, I remember running into the same thing with all the available four speed overdrives. My dad's old '81 F100 with the 300 six had a four speed overdrive, with reverse being up and left. My '87 had a four speed overdrive and reverse was down and right, like a traditional five speed without fifth.

I have a factory service manual for '87 and it contains information about T18, T19, NP435, TOD, and RUG (E150 only, also shown as SROD) manual transmissions.

 

According to a thread on another forum the NP435 and T18/19 transmissions had reverse to the right and down while the SROD was up, to the left and had a reverse lockout feature that required the shifter to be pushed down to get it into reverse. I have a NP435 at home and can check the shift pattern later today if needed.

 

I've had both an NP435 and a T-18 in Ford trucks, and seen/driven a couple more. Reverse was down and right on all of them BUT I also saw a late 70's Ford F-150 with one of the two in it and reverse was up and left.