Need BW1356 transfer case rebuild help!

[DrCharles]

My transfer case rebuild is driving me nuts!! I just went through it and replaced all bearings, seals and shift fork pads. I'd gotten the 2WD/4WD dog collar backwards too, so 4WD wouldn't engage. Took it apart again and fixed that. Everything working fine on the bench.

So I bolted the tailshaft on - and the input and output shafts are bound up together so tight that I can't turn the input and output separately by hand in N, and in 4L I can't turn any shaft either (since input and output want to turn together, but are supposed to be going through the planetary reduction).

I removed the tailshaft housing and now I can turn the input separate from the output, although it's "stiff" (not spline engagement, just friction). The only thing the tailshaft does is guarantee the output ball bearing stays in place, since IIRC there is a lip in the case, maybe a snap ring too so it can't go any further into the case.

WHAT can be so tight that the pressure against the output bearing race is causing the input and output to bind together?? The only thing I can think of is the new bronze I/O shaft bushing is too tall and it's taking up all the clearance plus a few thousandths. Please let me know ASAP if you've seen this and what to do about it! I don't dare "run it until it wears in"... and fill my case with bronze glitter....

thanks
Charles

 

[chillman88]

Never been in a 1356 but I'd assume they're similar to the ones I have.

Last case I did had both needle bearings and a bronze bushing in the input shaft that the output shaft rides on. Are you absolutley certain you got them fully seated?

Are you sure you put the input and output bearings in facing the correct direction? Some of them have a slot for the lock ring that is offset to one side, if you happened to get it backwards it might go in but won't be properly seated.

Are you sure all the snap rings fully seated when installing them?

 

[chillman88]

You must be registered for see images

30 and 31 should be the parts I'm referring to at the end of the output shaft.

 

[DrCharles]

Thanks chillman! I'll be going back into it this morning. Only a pain because of the sealant mess every time I split the case halves. Didn't sleep well racking my brain over what's wrong! But glad I found it before putting it back in the truck...

I couldn't find a spec for endplay on either input or output, but there appears to be none now, actually interference. What is odd is that the pressure from the flange on the tailshaft housing could only be moving the output bearing a tiny amount due to the snap ring on the inside. I tried carefully tapping on the outer race with a brass drift and it appears to be fully seated.

I looked carefully at the bearings before installation and they appeared perfectly symmetrical. No chamfers, recesses, "this end up", etc. I'm certain that all the snap rings seated.

Here I have to admit that I changed the fat bronze washer (31) but did not do the needle bearing (30) down inside the planetary. It did not look worn and I don't have the proper tools to pull it out. Before I tightened down the tailshaft, in N the input and output shafts were easy to turn in different directions with my fingertips so I think that bearing is OK.

Is it possible that the planetary/input shaft is not fully seated in its bearing? That would remove all the endplay and cause this binding at the bronze bushing. But I'd think that the pressure of pulling bolts down would have moved it. I'll try smacking it with a plastic hammer once apart, too.

Hope I don't have to remove the oil seals which tends to destroy them. Doubt they're available at O'Reilly... I hate transmissions! Full of hard-to-handle snap rings and sliding parts and other troubles

 

[typ4]

And its one of the simplest t cases to fix. I bet your front bearing needs a whack.

 

[DrCharles]

I found the problem! The bronze bushing (#31) in the kit was several thousandths bigger (in outer diameter) than the old one, which was in decent if not perfect shape. It hadn't even gone into the bore on the planetary which was obviously the source of the binding. I tried driving the new one in part way, but then the ID compressed and the shaft was way too tight.

Rather than mess around honing it, trying to file the outside, and probably destroying it anyway, I just put the old one back in. Everything went together like it should and there is endplay... Now I'm going to put it back in the truck. I'll put the new shifter in first since there's more room to work.

That's what I get for buying an inexpensive ($55) bearing and seal kit, I guess! Even though they've sold a lot of them on ebay with positive feedbacks... At least the bearings seem smooth and properly sized. Oh well, live & learn.

 

[chillman88]

Glad to see you got it fixed!

 

[DrCharles]

Me too I looked closely at the drain plug after it was all back in the truck and sure enough, some passing gorilla had overtightened it and put a tiny hairline crack in the boss. Which seeps a little.


So I backed the plug out a turn (still a decent torque especially with thread sealant on it), cleaned the area carefully, and used a finger to push some Permatex Aviation Sealant across and worked it into the crack. No leaks at the moment. If it weren't magnesium I'd just put a tack weld with the MIG on it, but I doubt anyone would dare braze or weld it in the truck! Nothing would put it out if it caught fire...


I wonder if it can be soldered?

 

[typ4]

No it cant, tig welded with mag rod only.
This a case where JB weld is your friend.