It's better but there are still issues with reverse needing a moment with the clutch out to engage cleanly. Even so it will pop out of reverse occasionally, though few and far between. I will likely have to pull the trans again at some point and inspect the 5-R fork for weak and proper engagement of the slider. I can live with waiting a second to engage reverse, I can't live with popping out as that will cause further damage if allowed to persist.

Aside from that, 1st engagement is not perfect but is much smoother, 2nd is fine. No issues with any of the forward gears or synchros.

 

reverse idler gear shaft play?
probably has nothing to do with popping out of reverse though.

 

Cadunkle,
Thank you so much for taking the time to write all of this, even though it seemed that no one was reading for a while.

I have a Bronco with a built up 300 and an NP-435, but am going to be swapping to a ZF5 here in the near future. I pulled a used ZF5 out of the junk yard about two weeks ago. It goes through all the gears fine and looks in really nice shape, but I'd still like to rebuild it before I put it in. I put about 4,000 - 6,000 miles on my Bronco a year. It's a daily driver, long distance traveler, and off-road camping rig, so I need to be able to trust the transmission.

A thread like this is a good eye opener of what can go wrong and what to pay attention to when rebuilding. So, again, thank you.

I've never rebuilt any transmission before (although I have done just about everything else), so I'm reading up as much as I can before I tackle it. (I also have plenty of time, as the vehicle still has another transmission in it until this is done).

In hindsight, what would you say the list of "gotchas" are that someone should absolutely be sure to double check and watch out for? Sounds like making sure snap rings are seated, forks aren't too worn, etc. Anything else?
Also, can you list what tools do you use to disassemble / assemble it? I've seen listings of specialty pullers, but they're hard to find and I don't see them in your pictures.

Thanks!

 

Makensure snap rings are seated. The ZF snap ring kiys have several rings in each diameter, varying thickness. Special attention to 3-4 synchro body snap ring.

Replace the synchros while it's out. 3rd gear is worn out on all of them, the rest are not far behind.

Worn needle bearings make it rattle, may as well get the full kit.

No special puller collets required. After removing snap rings from synchro body, heat the synchro body with a torch then drop the mainshaft onto a block of wood a couple times. Synchro body drops right off. Be sure to clean the holes in ends of shaft with a pick, for any woodbor debris in there that could get to the pilot bearing.
Other tools, large 3 jaw puller, 2 leg puller with extensions. Cheap pullers will get you through once or twice but good pullers are worth every penny if you wrench on stuff. Won't use them often but when you need them, you need them.

Get main and countershaft preload right.

Cases wear out around main and countershaft bearing races. Mess with them as little as possible. Peening the race area of the case along with some bearing and.sleeve retainer works of a slightly worn case. Keep it dry at least 24 hours after assembly though.

Measure your shift fork pads and slider grooves.

Use new sliders, they're cheap.

Check all gear teeth for wear, replace gears with abused or rounded over teeth. Third and reverse are the usual suspects.

 

So i changed my clutch in my zf5 put it back in then changed my fluid and found this in the drain any help

 

I believe that's the reverse lockout thingy.
I'm guessing someone dropped it during assembly and didn't bother to go looking for it. It goes at the top of the transmission under the shifter.

 

Yes that is the reverse lockout, it goes under the shift tower. There is also a spring that goes over the pokey end of it and sets against the main case. Without this you can engage reverse directly from 5th... Well maybe not engage but grind the heck out of the teeth for sure if you're not careful. Also, looks like a lot of metal in the fluid. If so, something is wearing.

 

Cadunkle,
Thank you for that useful information and the time of writing it up. Much appreciated!

 

@cadunkle

Thanks for the great write up. I hope the learning curve is a little less steep for me as you have done a great job outlining your experiences.

 

I'm glad it was helpful. It's not rocket surgery but you need to pay close attention to a few areas and be gentle with the races and case. I still have the S5-47 main case, one of these days I'll bring it and a race to a machinist and see what can be done. In any event, I'm glad others can learn from my pain.

 

I missed all the updates to this thread apparently. I think im seeing the wisdom in not screwing with the inside bits of transmissions lol. That said, with over 300k and the extra power running through it, ive often debated myself over having it rebuilt as a preventative maintenance measure, or run it till it pops and figure out how to install a zf6 or nv5600 (maybe even the dreaded E40D if i dont get somewhere with finding a dual disc clutch setup for a reasonable price). My zf doesnt have any glaring issues, 2nd synchro is getting a bit worn, reverse can be tricky if its cold, but it does get hot towing, even exclusively using 4th, ive hit 265* once, over 240 several times, running valvoline dex V.

Ive been told by a few shops that the ZF5 is a particularly tricky manual to tackle. As to your reverse not seating, that i can shed some light on, common problem apparently with the s47, had more than a couple shops tell me that the fork bends a little causing reverse not to seat all the way and that s47s dont have as deep of a reverse? maybe also something to do with the reverse synchro. Sounds stupid, but thats the gist of it that my brain remembers, as i said at the beginning of the thread, im not much of a trans guy.

Since were on the subject, you clearly know things about this transmission that i do. What suggestions do you offer to help me not hurt it with my 110cc pump? I try to tow mostly in 4th if im over 10k and /or on hills. WOT pulls in 5th are kinda fun tho, gotta put them fancy electric diesels in their place from time to time.

 

Very detailed write up, Thanks! I am having the identical squeak coming from my clutch. Just did a cummins swap with a new to me zf5. I tore the trans down and did not find any issues except some wear on the reverse synchro. I did not tear the entire main shaft down however, like you I need to get the truck on the road for now and everything looked pretty good. The clutch, flywheel, pressure plate, throwout bearing, pilot bearing, clutch fork slave cylinder are all brand new. When I put pressure on the clutch fork
(with my hand) the noise would go away. I put a small spring from the clutch fork to the side of the transmission and the noise was no longer constant but still came and went it seems to be most noticeable when I let off the throttle (while driving) or accelerate hard. I noticed you replaced your throw out bearing the same time you fixed the bearing race that wasn't staying in the case, do you think the squeak was the throw out bearing or the race in the case? Its hard to think my brand new throw out bearing is junk but it wouldn't be the first time. I'll add that when I had the transmission apart the race stayed in the case. Thanks for any input, much appreciated.

 

A guy at a transmission shop was supposed to figure out why my reverse went out. The only thing he said was wore out in the trans was the shift fork. I believe my pushrod bushing on my clutch is the real culprit. Anyhow, he had it since February and I'm just getting it back a few weeks ago unfinished because he kept saying he had other stuff to do. Got new seals everywhere.
I'm currently trying to get the transfer case pushed on the gears but the rails that go through the shift fork are uneven when I set them on the synchronizer sleeve. The 2 grouped up are even but the one that sits by itself is longer for some reason?? Because its longer, it will bottom out faster in the holes of the transfer case.
Please help. I've got a week to get it back in my truck so I can take final exams. I can't afford how much they charge to take them online at home.

 

Here is a picture of my problem. They're not lining up

 

Are all shift forks and sliders positioned in neutral? Are the pins through the each fork and rain intact? Measure depth of each shift rail bore in the tailhousing and ensure the rail will fully insert and is not hanging up on a damaged bore or damaged end on the shift rail. If the fork it bent it would also put the rail in the wrong position. I don't know that these forks tend to bend so much as the pads wear down. There is a minimum spec and the thicker the better, but no worn shift fork pad will put the rain that far back when the others are in neutral.