4spd to 5 spd tranny swap

[party2849]

I own an 84 bronco XLT with a 351W 4 spd manual. I let my friend drive it and he was shifting from 3rd to 4th and missed it and went into 2nd instead. All i heard was teath breaking and then about 500 yards later 1-3 gears would slip clunk while it was in gear. Sounds like a tranny drive gear. If you think that it could be anything else let me know. Differential should be fine, it is smooth while not in any gear. anyway, I am going to have to get a new tranny i beleive. I would like to get a better zf s542 from like an 88-91 bronco. i know that it will bolt up to the motor and the shifter will be in the same spot. However, will the old transfer case bolt right on, and what about the clutch and flywheel, driveshaft and will I need to get any other additional parts besides the tranny? Anything to help me with this, from where to get it and how to put it on. I havent messed around with trannys very much before. Thanks

 

[factotum_sid]

Ya, I'm currently getting ready to do the same swap with an 1986 Bronco with a 302FI/ 4spd and I have rounded up a m5od but information on adapting to transfer cases are limited and any forum I've read the subject always gets changed to how somone should swap to the ZF5 instead or else keepthe 4 speed because they are better for off roading. I imagine swapping is a pretty simple bolt in as both the engine and transfer cases had 4 speeds or 5 speeds depending on the year, but I can't find anything or anyone who says that it is or is not easy/possible/direct whatever. The other swap I can't find anything on is putting a 2wd zf5 mated to a 400ci in my devorced transfer case '73 highboy. Oh well, maybe I'll find info sooner or later.

But ya, as long as your zf5 has the small block housing and the flywheel and clutch stuff goes with the same motor it should be ok. I don't know yet about transfer case adaptablilty or x members. Seems like the zf maybe a bit longer?

 

[Justshootme84]

While the ZF series 5-sp manual wasn't ever offered in a Bronco, they were available for both big block and smallblock motors. There was a link I posted in a thread a couple of years ago (try a search), I think it was for Motive gear. Anyhow, the Ford transfer cases share the same bolt pattern for the various auto and manual trannies offered for the Bronco and F-series trucks. However, each t-case has a specific shift linkage length and bracket mount to the tranny. In general, the ZF trannies will cost quite a bit more than the 4-speeds, but are a much stronger option over the Mazda 5-speed OD. If you know what 4-sp you broke in the 84, that would help to decide if it's worth fixxing or should be swapped. There were at least 4 models offered in the 80s: TOD, T-18, T-19 and NP435. The TOD is prone to problems, the other 3 are worth fixxing unless you want to go to the ZF's. I believe the ZF's use a different type clutch (hydraulic) compared to these other 4-speeds. too. JSM84

 

[factotum_sid]

Ya, I think my 86 already has the hydro clutch, but an 84 would probably need to be converted over if a newer zf (or m50d)was being swapped.

 

[LOSTinthewoods]

My 84 had a hydrolic clutch and a t18 stock. I think all the 3rd generation broncos had hydrolic clutch systems i know the 2nd gens 1978-79 had manuals.

All of those 4 speeds have an external ***** cylinder the 5 speeds have an internal ***** cylinder, this means you will need the internal ***** and a new longer line. The 4 speed clutch may work for the 5 speed but i would change it to a 5 speed clutch set up(pressure plate and disc) from an 88 or newer,you will definently need a different throw out bearing if you try to use the 4 speed clutch . I have just done all the research on all this stuff. Beacause i just completed a c6 to t18 conversion. I was gonna and still might get the zf if i find one for the right price. The t18 was out of my old 84 .

 

[Justshootme84]

Thanks for the post, LostITW. I forgot about the ***** cylinder difference, too. IF you have some more info on the auto to manual swap, maybe you can post that in a new thread or in the tech articles forum. JSM84