If you can do it for a reasonable amount, yes. I personally have several that need rebuilding, and I pretty much either have to learn how to do it myself or find someone that won't charge me $$$$ for one.

 

Maybe I shouldn't get into going through these transmissions, apparently I'm taking classes at the school of hard knocks, granted I'm doing this in a rush and not replacing everything I normally would. Drove it to the airport last Monday AM for a week away at work and could have sworn I hear a couple brief squeaks when transitioning from cruise to decel. Coulda been my mangled cheap China tailgate though, so I ignored it since I had to be at the airport. Got back Friday AM and it was fine for getting to the highway and on the highway but once I got on local roads I heard the same squeak briefly when transitioning from cruise to decel. Eventually I could easily reproduce it in any gear but 4th. Countershaft issue for sure since there is no load on the countershaft in 4th, it's just spinning free. By the time I got home it occasionally would make the same type of noise as originally at idle, though it came and went.

So I took a nap to catch the hour of sleep I missed on the redeye and got to pulling the trans and breaking it down. Nothing obviously wrong with the countershaft bearing race, though it came out easier than I would have liked. I made some calls looking for confirmation the case was likely to be my problem and hopefully buy one. Turn out ZF stopped making S5-47 diesel front cases. They're unobtainium unless you find someone with a good used one willing to part with it. Two places I called had good cores but wouldn't part them out.

The fellow I spoke with at Midwest was very helpful. I told him I had a good S5-42 front case from my original trans which grenaded and took out some hard parts and was thinking of trying to use that. He said it will fit the S5-47 tailhousing and guts just fine, just requires using the S5-42 shifter shaft. I compared shafts and other the 42 shaft is longer, and the cast shifter ball socket part has a different design pad for the detents of the spring ball on the shift tower. The 42 front case has a longer recess for the shift shaft than the 47 but the bearing is positioned the same distance from the shift tower hole. I suspect the 47 shift shaft would work in the 42 but not the other way around, though I just used the 42 shaft and cast ball socket assembly.

On disassembly I found aluminum debris in the pocket bearing. This could only be from the case itself or the shift forks, everything else is steel. I couldn't imagine that much wear on the shift forks so rapidly, so must have been from the case.






On setting preload today I found my 42 front case was junk. The front races felt like a normal press fit when installing but once fully seated on the shims would spin in the case if gripped firmly. Recall I'm leaving in a week for vacation and need the truck to tow. I checked Craigslist and found another ZF local, but the guy is away until Monday. I had a buddy coming over later to help install the trans, so I marched on sure my efforts were to be in vain. The 47 case seemed to be in better condition but I did not have any 1/2" (I think!) cup plugs for the shifter detents. The S5-47 cup plugs positively seat on a ridge in the case, I have not figured how to remove without destroying them. The 42 detent plugs sit free in the bore, you tap them just below flush with the top and can remove them without damaging and I have a spare set too.

So my course of action was decided for me. I used a center punch to make far too many dimples in the bearing race area of the case for each of the races, slathered the race and case with Loctite 620 sleeve retainer (all I could source today) and installed them. The races were a bit harder than I expected to drive in, a good thing I suppose. Good enough and in it went.

I did also put a new throwout bearing in. I had one on the shelf and figured I may as well at this point. Turns out the one I had was damaged, but I got one from the store and used that. I noticed the new throwout bearing fits tighter to the bearing retainer shaft. The old one spun smooth and easily though and only had about 7,000 miles, so I doubt it was an issue.

Test drive went well enough, no squealing noises. It did pop out of reverse when first backing out. Reverse is a little finicky to get in on this trans, I replaced the slider but not the gear as that's all I could get next day and it didn't look terrible. After a long enough highway run to get everything up to temperature I took a bunch of back roads. No noises. It did pop out of second twice when starting from a stop. I did not replace the 1-2 shift fork or slider. I did order a 1-2 fork but I received a 5-R fork instead so that was decided for me. I did not replace the slider, the teeth looked serviceable with minimal wear from what I recall. On testing many second gear engagement and application of load in the driveway I felt one time where it did not fully engage, likely the synchro was at the far end of travel by the time it synchronized the gear. Keeping light pressure into second and releasing the clutch until it just grabbed it moved fully into gear and held. Maybe as the synchro wears in it will improve, but if that is all it is I can live with it for this trip and until winter.

My plan is to buy the local ZF5 on Monday and keep it as a spare. I'll put some miles on the truck tomorrow to be comfortable with it but at this point I fully expect to be replacing the trans Monday, and if not I may bring a spare trans with me on vacation. I've got removal solo down to just over 2 hours at a casual pace and can probably shave a bit more off that. Install is getting faster each time too. There's a 2WD wide ratio 460 ZF for reasonably prices local as well, that would give the hard parts to fix the wide ratio diesel ZF with the failed 3-4 synchro hub snap ring... I could make it a 460 or diesel trans and recoup some money, and get rid of some of my parts. I'm knee deep in transmissions over here, not thrilled about it.

 

Well I've got almost 200 miles on the ZF and no bearing failures. I'll get some more miles before I leave for this trip on Saturday. I'm still trying to meet the guy to buy the spare S5-42. Supposedly that one works fine aside from being difficult to get into reverse sometimes. Not what I want as the S5-47 I'm running is very difficult to get into reverse even with a brand new 5-R slider. Reverse gear teeth didn't look that bad, but the slider was trashed so the gear must be too far gone. There's kind of a trick to it and every time in reverse I let the clutch out very gradually and am ready to push it to neutral so if it pops out it'll only grind a couple teeth lightly. Hopefully it lasts me a few weeks from home. I'll keep a come-along and straps in the truck if reverse gives out and I really need to back up.

Second is more consistent but pops out sometimes. It will always work if the truck is rolling, so I start in granny gear and downshifts at anything more than a couple MPH must be double clutched to fully engage and not pop out. Second gear is easily workable, reverse makes me nervous.

Hopefully I can pick up a spare ZF to bring with me, I could change it on the side of the road reasonably quickly at this point. I suspect if the bearing race has held this long it'll be good for a while. Hopefully until winter then I'll go through it and replace all 3 sliders, the 1-2 fork, reverse gear, and 2nd gear... And maybe look into having some machine work done on the case for a permanent fix.

I realized I hasn't posted any pictures showing the bearing races, for anyone interested...

 

Seems like you've had quite the bad luck, I always thought those were pretty good trannies other than the fact they don't shift well without a clutch.

They make nv4500 conversion kits for our trucks, a little pricey but might be worth it if you're going to have to buy a tranny anyways. Iirc it's somewhere around 3k, which is kind of outrageous but at this point so is all the frequent zf failures, I love my four speed and there a breeze to work on but the overdrive is nice if you need to get somewhere quick

Most of the time whoever passes me out on the open road gives me an odd glance when I meet them at the same stop light in the next town though.

Very interesting read, really digging all the pictures!

 

I had considered a NV4500 swap when I was breaking ZF cases with my 460 truck, mostly cases as I only recall one internal failure. One I put a solid motor mount on the drivers side case failure rate dropped significantly. The issues with NV4500 is there is no fix for the weak 5th gear that I'm aware of. Once the factory gear fails you only have good used factory gears if you can find them or china repops which are weaker and fail easier. Towing in 5th makes it a ticking time bomb is my understanding, which makes it a no-go for me.

So my options (that I can think of):
1: Suffer through this and end up with a solid S5-47 eventually (maybe sleeve the S5-47 front case when I replace the remaining damaged hard parts)
2: Swap to a ZF6
3: NP435 + Ranger overdrive

At this point if I keep having issues I'll be leaning towards a 435 and Ranger unit. Torque rating won't be as high as the ZF6 but it'll offer more gears. Over 200 miles and no more bearing failures, getting better at successfully engaging reverse. I'll change the oil before I leave Saturday evening even though I think I did a reasonably good job of getting the aluminum particles cleaned out.

 

I was under the impression that the fifth gear failure was due to a nut backing off and all you had to do to prevent it was tech weld the nut on?

Any reason why your considering the np435 vs a t19?
I think the only reason the t19 gets a bad rep is because of the tall first gear in the diesel trannies, Ford actually had a wide ratio conversion kit just to change the gear to the gasser one..
Or you could find a 460 version, there probably easier to find than the diesel one

Only drawback with the four speed is that crappy cast aluminum forward bell housing. Mine actually broke in two pieces and has been welded back together by a local guy. It just started cracking in other spots so I found a spare at a junk yard. I found three and they were all cracked as well so I picked the best one..

 

The S5-47 held together for the long tow for vacation and back. I got a lot better at knowing when reverse is actually engaged and won't grind, though it often takes a few tries. Only had one time it popped out and ground in second, a hurried downshift double clutched of course.

There's a bit of rattling occasionally at lower RPM in first and second, allegedly normal for some ZF5 but most I've driven have not done this to the extent of this trans. I attribute this to the rebuild kit I got not coming with needle bearings between the gears and mainshaft (no wonder it was a bargain), so I reused the old needle bearings. First and second felt very slightly play on the shaft when rocking at an angle, hopefully new bearings will tighten it up.

Now to source some hard parts and decide when I feel like pulling this trans yet again. I'd like to find a machine shop that can repair the S5-47 front case so I'll ask around, maybe have a pair of setup bearing races made as well to minimize wear on cases if I end up doing more of these. It's tempting to just be extra careful in bearing removal from the mainshaft and reuse them along with the S5-42 front case that has not spun a race so far with the dimpled case and sleeve retainer.

 

this is quite an interesting thread-and unusual bad luck with a good trans design.
rebuilding these is relatively simple as u know -if i have the pullers and drivers.
which i don't have.
most of the zf's ive seen that are toast are due to low or improper fluid., heat build up , scouring or case damage.
i dont rebuild mine i just tear them apart cause i like gears and transmissions, then i take the best parts to rebuilder
who, has a steady trickle of customers for this transmission, so if you do this as a sideline-dont quit your day gig. this fellow does about 4 a month.he is fast and cautious, knows the hidden time bombs and gives me a servicable product for 500.00 but thats mostly labor as i supply hard parts and rebuild kits. otherwise he is 1900 to 2300.


anyway great thread. i want to call your attention to a clever item on this case. there is a plug just behind the clutch lever its 1/4 inch or so. it is a passage onto the main shaft and the input bearing. it looks like zf designed this as a path for plumbed fluid cooler. but t ford didnt use it. we are speculating that a small pump and a pick up at the bottom of the pto plate could feasibly cycle oil through cooler/filter and back onto the input shaft then of course throughout the trans.

by "force" oiling i wager the common fail issues with this trans will go away.
whats your opinion on this?

 

Interesting thread. I've got two zf5s, 1 in my 87 6.9 and one in my 94.5 7.3. I've never had any issues with either. A couple years ago swaped out the 4 spd in the 87 for the zf due to the aluminum bell housing cracking at the slave cylinder mounting local. Anyhow I haven't looked or searched because I've never needed to, but where have you found a zf5 troubleshooting guide for future reference if the need shall ever arrive?

 

the t 19 is a common transmission.....
the question arises of course " was there ever a cast iron bellhousing for that transmission behind a IHC diesel.....
solving the aluminum bellhousing issue and allowing the ranger overdrive. something i had never considered until this thread , but offers curious and appealing possibilities....

or for that matter a 5 speed medium duty eaton transmission.... very few offered overdrives but 5th can be flipped....

hmmmm

 

Trying to work up the motivation to do this again, hopefully for the last time. I'll probably be pulling the transmission soon.

 

i feel ur pain, just lookin at the picture. u must be near my age if that feeling creeps over u when contemplating a big job with uncertain outcome

 

I got it pulled fairly quick but ran out of steam. Don't feel like breaking it down tonight so I'll get on it tomorrow. If I'm real ambitious I'll have it back in tomorrow, I'm not counting on ambition though.

 

what is that transfer case??

 

Transfer case is an NP208.

I got the mainshaft broken down. Remember when removing sliders to use a pick and remove the synchro keys lest they get all springamathingin' around the shop. I forgot when using the puller to pull 3rd gear using the slider. Oops, but I found them all. No problem either way as I have 9 new keys and springs to install in this trans. On a S5-42 you won't be so lucky as the keys are traditional spring and ball with retainer style.

Taking a break then reassembling with new 2nd and reverse gear and respective synchros, 3 new sliders, all new needle bearings, new rear mainshaft bearing, new 1-2 fork. This better fix my problem because at this point essentially everything is new.