I am looking to change out my manual transmission in my 79 f150. I want to put a 5 speed in it but still keep my manual clutch. I have a 300 engine that I also want to keep, can I just put a late 80's early 90's 5 speed tansmission in it and keep my original bell housing? Can anyone provide any guidance on this issue for me?

 

Welcome to FTE. Your question is the same one I was trying to answer when I found this site.

The late model Mazda and ZF trans use an integral bell and require a hydraulic clutch.

A T5 from a V8 Mustang can be made to work with a $150 adaptor. This is a car trans, and you'll be best served with one with a 3.35 first imo. OD is a bit tall, but depending on your axle, you might be OK. No heavy loads or towing much if anything.

There are other Tremec transmissions as well, like the TKO that are stronger.

Back to truck transmissions. The NV4500 will bolt up, again with an adaptor.

OK, back to the beginning. Which 4 speed do you have? Are you just looking for lower cruise rpm or what? Do you have a 9 inch rear axle? If so, you can just put some Bonneville special gears in there and use your granny first--if you have one. If you have the OD 4 speed, the 5 speed will only fill the gap between 2nd and 3rd, the OD will be the same.

Good luck. I have some links I can post depending on what you want to do.

 

Please post your links. I have a 87 f-150 ex-cab, 300-efi with a 4mod. The gap between 2nd and 3rd is what is the problem for me. I live on the coast, hills, twist and turn. Not looking for speed, just to tow the trailer without a missing gear.

 

Depending on your trailer weight, the Mazda box might work. Otherwise, the ZF is the answer. Both pictured here:

Domestic Truck Tranny Guide

I wouldn't go for the T5 for towing--first is too tall, OD too tall. (unless you go with 4.56 gears---)

I hate that 2nd/3rd gap--kills you on the back roads. 35-50 mph just isn't happening up hills....

 

Either 5 spd that would fit your motor will have an internal hydraulic throwout bearing/slave cylinder. You will need to change to a hydraulic setup to use the M5OD or the ZF. The diesel and BB ZF has an external slave cylinder, but as mentioned previously, the bell housings are integrated into the transmissions and therefore are not interchangeable.

 

It has been a long time since I have been back here, but I did swap my 4 speed for a ZF S5-42 5 speed out of a 1989 f250 with a 351. It bolted right up and used all original flywheel, clutch, pressure plate, and starter. I used the cocentric slave cylinder and mounted the master cylinder on my fire wall and slightly modified my clutch linkage to work with the master cylinder. I used a BW 1356 transfer case and shortened my rear drive shaft. I found a driveshaft in the junkyard that fit perfectly for the front. My original speedo cable fit into the new transfer case and I just swapped the gears of the end. My speedo reads right on the money. I did have to trim underneath the cab to make the zf fit properly and and I used a piece of 6 inch channel iron for my cross member and bolted it to the bottom of the framea nd swapped out the original cross member/radius arm support for one from a 1972 f250 2x4. Everything works great and fits tight but it does fit and does not rub. Thanks for all the help!