I have an 85 F150 4x4 with the 300-6 and the four speed manual with the granny low 1st gear. I will be needing a clutch soon and I may also be losing one of the synchros, so an overhaul may be imminent. I just got this truck for my kid so am not familiar with my transmission choices. Can I replace this transmission with a transmission that has an overdrive? I am only interested if it would be a bolt on replacement or a relatively simple conversion. If so which transmission would I be looking for? Thanks.

 

Best choice is the ZF 5 speed. Retains the low first, has OD in fifth.

Scroll through the transmission section, lots of discussion. Not cheap.

Others can be had like the Mazda 5 speed, which does not have the low first, or the OD 4 speeds, which most people dislike due to tall first and gap between 2nd and 3rd.

 

So Ford didn't offer a 4 or 5 speed overdrive in this year?

 

In the early 80s Ford did offer an overdrive 4 speed manual trans. (someone correct me if I am wrong) I believe it was the Clark single rail over drive (SROD). It was a decent unit as long as you didn't beat up on it, or tow tremendously heavy loads with it. My vote goes for the ZF 5 speed, they are every bit as strong as your 4 speed granny box. Really the only thing I can see that the 4 speed might have on the ZF is the cast iron case versus aluminum. Ford used two different 4 speeds with granny first...Borg Warner T18 and the New Process 435, both are concidered bullet proof from a strength stand point. I have an 84 F150 4wd 300 six with the NP435, it started to show wear at around 185-190k...bearings were starting to make growling noises and it was becoming more and more difficult to shift. I ordered a complete overhaul kit from Bronco Graveyard, it cost $165...came with everything but the gears; all new bearings, thrust washers, snap rings, syncros, bushings, gaskets, seals,...everything. The cost for the rebuild kits were the same for both the T18 and the NP435. It wasn't too difficult to rebuild, just set up a nice clean work area where you can lay all your parts out...take your time and it will work out fine. Hope this helps, good luck!

 

neither the NP435 nor the T-18 have overdrive. the 4th gear is 1:1 on both. the SROD is a tremec transmission, and has a close cousin called the TOD. These transmissions are fine, despite complaints, and both have overdrive. They just aren't as heavy-duty as the T-18/T-19 or NP435. the TOD is the better choice, and will bolt right in place. I don't recommend the ZF, because it's going to require some clutch modification. your clutch setup won't work as it is now with the ZF. The Mazda M5OD will give you the same problem. if you want bolt-in overdrive, you have to go with the SROD/TOD.

 

OK, thanks, that's the info I'm looking for. Were these units used on my model year F150 or a different set of years?

 

Hey Savage, when you say the ZF 5 conversion will require clutch modification, are you talking about pedals/cables or the clutch itself?

 

Yeah, as a rule, any F-100/150 from '80-86 is a likely candidate for one of these transmissions. you can spot them easily from the inside of the cab because they don't have the funny multiple bends in the shifter like the NP435 and T-18/19 have. The technical name for them is Tremec T170FS for the SROD, and T170FT for the TOD.

btw...when i mentioned clutch modification, i'm talking about the hydraulic setup. the ZF and the Mazda have internal slave cylinders, which are incompatible with any other transmission's hydraulic clutch setup.

 

I agree w/ savage. im lookin to get a new tranny w/ overdrive myself. as he said, the TOD is a DIRECT bolt in. the ZF may be a 5 sp w/ granny low, but u have to do a lot of modification to make it work. if ur son isnt gonna be towing more that 2 ton, the TOD is the way to go. From what i hear it is the better of the 2 overdrive trannies. I have a T-18 (granny low non synchronized 1st and reverse but sync 2-4) backed by 4.10s and a 300 I6 and i get HORRIBLE gas mileage. i pulled a 99 f-250 of of a mud hole no prob, but my pocketbook is KILLING me.

Savage- thanks for the clue man. if i went to a TOD, it is possible to keep the same shifter/stick? im tryin to do this behing my dads back... hell klill me if he finds out LOL... and im sure every1 lookin for a Tod or SROD has this quest... how do u spot a TOD/SROD in particular... is the a specific Vin code to look for or door sticker code? If so what is it?

 

you might be able to keep the same shifter...you have to pull both of them out and look at the bottom of the shaft. they have a collar that unscrews (by hand, hopefully, channel-locks if not) and they pull right out. as long as the selector ends are the same length and basic shape it will work. you could also tell the old man you got a new shifter...it'd be hard to notice the non-granny 1st though! i don't know if you can identify them from the door sticker or vin plate...anyway, i don't know the code. however, both are aluminum! they are the ONLY aluminum-case transmissions (with a separate bell-housing) that ford had. so if you look under the truck, the tranny won't ever be rusty. the casting code for the SROD is RUG, and the TOD is RTS. the SROD gets its name from the single shift rail it has on its side. the shifter is also mounted on the tailshaft, so it won't fit in without cutting a hole in the floor. the TOD has the shifter on top, same place as the T-18.