Rebuilding ZF5, looking for preload shims

[TheBirdman]

Holy cow I just went back to the manual since I apparently didn't get that part, and you're correct. There's no way to measure pre-load with the shims installed, it has to be with them out and you do the math for pre-load. Great. Well the transmission works OK as-is, but the synchro cones are too worn and still chatter. I guess I get to tackle all this again someday, assuming there are real shims on this planet.

Actually if I could put forward a silver lining: now that we know yours has been working fine since then, Im a bit less worried about getting the preload perfect. Thinking about things, I dont think theres much damage that could be done by having it a bit loose, aside from shifts perhaps being a little sloppy, or having a bit more rollover noise from the gears rattling. The way helical gears work, as they torque up, they change a lot of the force pushing away from each other into lateral force, so under torque, they are still pushing themselves into the tapered bearings. What does the synchro chatter sound like? How badly were the synchro rings worn before you put it together? A few of mine had some pitting, but it didnt seem too bad to me.

As for shims, Im going to take the old shims to a trans shop tomorrow morning and see if theyve got anything close, otherwise another idea a buddy of mine turned me onto was having some shims laser cut from flat shim stock. Where theres a will theres a way. Worse case scenario, I could see myself adding some wax paper shims to the countershaft, thats how you set the axle tube to wheel bearing clearance on a swingaxle vw beetle.....crazy nazis....

 

[franklin2]

From my limited research into manual transmissions, you are correct the helical gears put a side load on the shafts. Accelerating it shifts to one end, and decelerating it shifts to the other end. I have read that if this gets excessive, it will cause the transmission to pop out of gear during accel and then decel.

 

[TheBirdman]

Okay, I drove around today and couldnt find a trans shop that had any shims, but I found a tip in another thread that Nogalitos Gear had some shims, so I called them at (210)-923-4571, and sure enough, they had the whole set in stock, so its on the way to me for a bit under $70. I had already ordered some laser cut shims from Sendcutsend, so I guess when they show up Ill have a decent little pile of extras. Ill post an update when I get them in and working.

 

[TheBirdman]

Nogalitos sent me the invoice, they have the main shims listed as "NV16811 - NV4500 M/SHAFT ZF542 ZF547 - INPUT SHIMS G56 MERC 6SP INPUT"
and the countershaft shims listed as "NV20743 - ZF542 ZF547 FRT C/S SHIMS - NV5600 REAR C/S SHIMS"

So for anyone in the future looking for shims, perhaps that helps you.

 

[TheBirdman]

well, I got all the shims, and I ended up using half shims from nogalitos and half laser cut shims form sendcutsend.com. The laser cut ones I had to sand the burrs off the edges a bit.

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a 40 and 15 on the main side got me to 56, and a 15, 22, and 40 on the countershaft side got me to 77. 4 thou of preload on both shafts.

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The countershaft race was pretty loose in the bore, so I put it in with bearing retaining compound and staked in the aluminum a little.

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I bolted the shifter on and it ran through all the gears fine, with no hideous grinding noises, so Ill count that as a win for now. Does anyone know if the T19 shifter stick will bolt on to the ZF5 shift tower?

 

[KansasIDI]

Does anyone know if the T19 shifter stick will bolt on to the ZF5 shift tower?

It does not

 

[Old Goat]

The T-19 does not bolt to anything, I drops straight into the
Transmission. There is a Bell shaped piece that slips over the
shift lever and screws onto the top of the transmission tower.

Painting your Transmission yellow, makes it easier to see if you have a leak.
I painted my Oil Cooler John Deer yellow when I replaced it 5 ys ago, for that reason.

Goat

 

[TheBirdman]

It does not

excellent, thanks.

The T-19 does not bolt to anything, I drops straight into the
Transmission. There is a Bell shaped piece that slips over the
shift lever and screws onto the top of the transmission tower.

Painting your Transmission yellow, makes it easier to see if you have a leak.
I painted my Oil Cooler John Deer yellow when I replaced it 5 ys ago, for that reason.

Goat

I was bored waiting for the shims to show up so I did the transfer case yellow, my thinking was that yellow things get a good look once theyre covered in grease and dirt and soot. The spotting leaks thing sounds like a better excuse.

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[The_Josh_Bear]

What does the synchro chatter sound like? How badly were the synchro rings worn before you put it together? A few of mine had some pitting, but it didnt seem too bad to me.

It sounds like a bunch of teeth trying to engage each other a decent speed and just bouncing off, lol. Cause that's what it is! Honestly it's hard to say but quite metallic sort of grinding but sharper than grinding. Depends on how hard you push the stick. The actual teeth on the gear hub sleeve and the synchro cones in general had some damage from "grinding" the gears over the years. I sanded some of them down and left the rest as I got sick of it and hoped for the best.
My rings were worn past the kevlar/whatever the friction material is called in places. Because of that I didn't think the cones would be in terrible shape, assumed they were good enough and put it together. I was wrong! But no pitting or obvious damage. The cones looked good according to the book, but I should have measured the cone to synchro ring gap per the book anyway.
For the record, I can't find a source on the cones, so not measuring them is really chapping my hide. Maybe there's some sort of break-in period for these synchros? I seem to be the only one with the issue, so prolly not.

Nogalitos sent me the invoice, they have the main shims listed as "NV16811 - NV4500 M/SHAFT ZF542 ZF547 - INPUT SHIMS G56 MERC 6SP INPUT"
and the countershaft shims listed as "NV20743 - ZF542 ZF547 FRT C/S SHIMS - NV5600 REAR C/S SHIMS"

So for anyone in the future looking for shims, perhaps that helps you.

Thanks so much for this!
Allstate Gear currently has both sets in stock, the only retailer I could find that did. $50 shipped to my place in WA.

 

[TheBirdman]

just a quick update for anyone curious, I finally got the truck off the jankstands and tried out the transmission, it seems to work fine. A bit of rollover noise when lugging the gears, but none in neutral. Time for a victory beer.

 

[IDIBRONCO]

A bit of rollover noise when lugging the gears, but none in neutral.

That sounds perfectly normal to me.

 

[onetonjohn]

How hard are these? Do you need special tools? Manuals available? I've done a handful of easier manual and automatic transmissions, but a little scared to dive into this one. I've got a good trans with a cracked case. I'd like to find a good case and swap parts. Or be able to rebuild the one that's in my truck.

 

[TheBirdman]

How hard are these? Do you need special tools? Manuals available? I've done a handful of easier manual and automatic transmissions, but a little scared to dive into this one. I've got a good trans with a cracked case. I'd like to find a good case and swap parts. Or be able to rebuild the one that's in my truck.

Finding the shims was the hardest part. Between the service manual and a few youtube videos I found, it was pretty easy, but I still took my time doing it. The only special tool I found I really needed was a special collet for pulling one of the synchro rings off, the rotunda T87T-7025-MH-NH-OH. I found one on ebay for $180, and I was planning on relisting it for about the same price now that Im done with it. The rest can be done with a few hammers and punches, I didnt even use my press.