Leaking Transfer Case - Best Kits for Repair

[BradL84D30M1008]

Yes, my u-joint at the rear diff will slide in the yoke......have a horrible vibration at 35-40 mph on the road.......so working my way from the front of the drivetrain to the rear.....presume best to replace rear yoke along with both rear u-joints? Or just replace u-joints and test fit whether still have slippage in the yoke?

Also check for bad 'U'-joints. They can cause such severe vibrations that the housing can break. I've seen this happen several times.

 

[BradL84D30M1008]

Who knows? As noted also have a bad u-joint at the rear diff - slides in the yoke.

Forklift?

 

[cucvrus]

I have that spacer if you should need a replacement.

 

[Chaski]

Yes, my u-joint at the rear diff will slide in the yoke......have a horrible vibration at 35-40 mph on the road.......so working my way from the front of the drivetrain to the rear.....presume best to replace rear yoke along with both rear u-joints? Or just replace u-joints and test fit whether still have slippage in the yoke?

So the caps are slipping in the yoke? Does the yoke still have the cast in tabs that retain the caps? The pinion preload on the 14 bolt is set with a crush sleeve, so if you do decide to replace the yoke read up on it before you start. The last thing you want to do is to attack the job with an impact and get your bearing preload way out of whack, causing bearing death.

 

[BradL84D30M1008]

Yes, caps are sliding in the straps.....I've not yet checked torque on strap bolts......they look fine.....but totally agree that replacing the yoke probably best left to skilled professional, which I am not!

So the caps are slipping in the yoke? Does the yoke still have the cast in tabs that retain the caps? The pinion preload on the 14 bolt is set with a crush sleeve, so if you do decide to replace the yoke read up on it before you start. The last thing you want to do is to attack the job with an impact and get your bearing preload way out of whack, causing bearing death.

 

[The FLU farm]

Who knows? As noted also have a bad u-joint at the rear diff - slides in the yoke.

My reason for suggesting forklift damage is that if a vehicle was bought at auction, all kinds of interesting damage can occur when lifted by a careless operator.
Let's say that the rear driveshaft was slightly damaged (bent or dented). Then nobody thought to look the vehicle over and simply drove it. That could injure, or kill, components at both ends of the driveshaft.
The new(est) owner then thinks that everything is in good working order. After all, it was a running, driving vehicle he bought, so he doesn't check for anything out of order, either.
Pure speculation on my part, but things like that do happen.

 

[BradL84D30M1008]

Totally possible......this '84 M1028 came from Ft Hood, Tx via Iron Planet, to an individual, and then to me via eBay......I test drove it at point of purchase, and knew it had a bad drive-line vibration of some sort at that point, and then drove it home ~ 50 miles, and have been addressing the issues since.

Drive shaft looks ok, no obvious impacts/dents/bends......transmission/transfer case were relatively dry at point of purchase, but later after arriving home, not so much........it's been leaking ATF obviously for some time for all the gunk accumulated, but is puddling now......my mechanic verified, and previous owner also said, that ATF level in the NP208 is right below the fill plug level.....so surely need to address ATF leak from transmission, and cracked adapter/spacer between transmission and NP208.....and u-joint(s) and maybe the yoke at rear diff....

My reason for suggesting forklift damage is that if a vehicle was bought at auction, all kinds of interesting damage can occur when lifted by a careless operator.
Let's say that the rear driveshaft was slightly damaged (bent or dented). Then nobody thought to look the vehicle over and simply drove it. That could injure, or kill, components at both ends of the driveshaft.
The new(est) owner then thinks that everything is in good working order. After all, it was a running, driving vehicle he bought, so he doesn't check for anything out of order, either.
Pure speculation on my part, but things like that do happen.

 

[The FLU farm]

Drive shaft looks ok, no obvious impacts/dents/bends...

Well, you can't really put a dial indicator on the driveshaft while the rear U-joint is flopping around. How about removing the driveshaft and check it for straightness before installing new U-joints?

 

[glaser06]

Well, you can't really put a dial indicator on the driveshaft while the rear U-joint is flopping around. How about removing the driveshaft and check it for straightness before installing new U-joints?

Less safe but lift the back wheels and put in drive works too if the new ujoints are already in. Use stands, not a jack and a helper.

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[The FLU farm]

Less safe but lift the back wheels and put in drive works too if the new ujoints are already in. Use stands, not a jack and a helper.

That's brutal on the dial indicator, don't you think? And even on whoever is trying to read it while the 'shaft is spinning at speed.

 

[glaser06]

That's brutal on the dial indicator, don't you think? And even on whoever is trying to read it while the 'shaft is spinning at speed.

Yeah, l usually just eyeball it. If you really wanted to I suppose you could use the brakes to slow it down.

Granted this is coming from the guy who's made and used 2"square tubing for driveshafts.....

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[The FLU farm]

Yeah, l usually just eyeball it. If you really wanted to I suppose you could use the brakes to slow it down.

Granted this is coming from the guy who's made and used 2"square tubing for driveshafts.....

Oh, I had forgotten about those. Okay, I wanted to. It bugs me that manufacturers can't make receivers and ball mounts with decent tolerances, but in a driveshaft application that slop takes on a whole new meaning. Lots of affordable travel, though.
Either way, it'd be easy enough to turn the driveshaft by hand instead of having the engine drive it and then slow it down with the brakes. In my case it'd be a lot easier, since I always work alone.

 

[glaser06]

For those who were wondering, the square driveshafts are for off-road use only. Stronger than a circular one and easier to manufacture a slip joint into for changing on the trail.

Not to say I haven't ridden to Taco Bell in the thing, dear God thats a rough ride. My gf always wants to take the jeep now for some reason though.......

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[cucvrus]

I just had a driveshaft rebuilt this week for Terminus M1009. That was both U joints balanced and all $169.70. That sort of takes the guess work out of it. I heard the squeaking Saturday at RC and was surprised to find both U joints bad. The yoke I replaced with a Yukon yoke from Autozone. I marked the nut and pinion. I removed the nut with a breaker bar and counted the revolutions that I turned it to remove it , replaced the seal and yoke and tightened the nut back up to the same point again. Checked it with the breaker bar and it was tight. Good enough. If you go crazy with the impact I am sure you could do damage. But just use common sense and you will be good. If I am wrong. Sorry It worked for me many times. And I learned it from old timers. Have a Great DAY.

 

[cucvrus]

GM 400 TH to NP 208 adapter mount/spacer 1987 M1028

Spacer pictures you requested. Just removed from an M1028.

 

[cobia2017]

my case also leaks, sealed it up twice, a reputable local transmission mechanic said that this case has a overflow vent on top and that it was overfilled and should stop as he took fluid down a little....anyone else aware of this? does this sound correct?

 

[cucvrus]

I think the rear seal of the transmission output shaft is leaking and needs replaced. This allows transmission fluid from the transmission to leak back into the transfer case and then it leaks out the over flow. Because unless they filled the transfer case from the overflow. How would it get any fuller then the filler plug hole? That is a 30mm hole in the transfer case. The fluid would come out faster then you could put it in. It is not a hard fix. Drain the transfer case. Remove shift linkage, 4WD indicator plug, both drive shafts, the 6 - 15mm headed M10 1.5 bolts that attach the transfer case to the adapter/spacer and replace the seal in the transfer case. Replace the output seal on the tail of the transfer case while you are at it. Reverse procedure and you should be good as new. Good Luck and have a Great day.

 

[cucvrus]

I may have confused the issue. The seal is in the front of the transfer case. I just wanted to clear that up. I know I had several that were always taking transmission fluid and then when I serviced the transfer case I seen that it was overly full. I sent it and had the repairs made at the transmission shop. I then seen the seal when I had a transfer case out and started replacing them myself.

 

[The FLU farm]

my case also leaks, sealed it up twice, a reputable local transmission mechanic said that this case has a overflow vent on top and that it was overfilled and should stop as he took fluid down a little....anyone else aware of this? does this sound correct?

Like cucvrs says, it's not easy to overfill the transfer case. Unless you're parked on a fairly steep downhill.
If the timing for a real repair is bad, for now you could open the fill plug once a week or so, letting any excess out. Just don't forget to keep an eye on the transmission's fluid level, as that's most likely where the fluid comes from.

 

[cobia2017]

ok, interesting, so basically the tcase overflow vent is for exactly just that-that is a leaking transmission seal (output shaft seal)...bc yes-how can one fill too much in tcase if using the fill hole as I can't imagine they use the overflow vent to fill it