4L60E 4wd odd problem

[Eman85]

@NickTransmissions I'd like your opinion on this
97 Tahoe 5.7L 4wd 200k mi. coming to a stop it started making a thumping, driven slowly a very short distance and parked. I towed it in and on the lift in drive, 2wd or 4wd it makes the thump. With the truck on the lift engine off and trans in neutral I can rotate the driveshaft in the forward direction with no problem. If I turn it the other direction it goes a little and locks. If I drop the shaft off of the rear it still does it so it's in the transfer case or the transmission. When it locks I can put a prybar in the yoke and force it past the spot and it rotates a little and locks again.
I had to get it off of the lift so I didn't get a chance to go further. Anyone got an educated guess as to what it is?

 

[jfoj]

Guess is more than likely the transfer case. If you already have the vehicle on the lift, it is pretty easy to drop the transfer case and then isolate the problem. You will need to drop the transfer case even if you need to pull the trans anyway.

As for a good place for a reman transfer case, check these guys out. This is pretty much all they do, they ship and from my experience have decent pricing.

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If you are looking for an OEM Quality Remanufactured Transfer Case or Manual Transmission at an affordable price then look no further! The Gear Shop has been remanufacturing our line of BULLDOG TOUGH Transfer Cases and Manual Transmissions since 1945!

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I purchased a reman AWD transfer case from these guys for my 2005 Yukon Denali and have had in the vehicle about 3 years with no problems.

 

[NickTransmissions]

@NickTransmissions I'd like your opinion on this
97 Tahoe 5.7L 4wd 200k mi. coming to a stop it started making a thumping, driven slowly a very short distance and parked. I towed it in and on the lift in drive, 2wd or 4wd it makes the thump. With the truck on the lift engine off and trans in neutral I can rotate the driveshaft in the forward direction with no problem. If I turn it the other direction it goes a little and locks. If I drop the shaft off of the rear it still does it so it's in the transfer case or the transmission. When it locks I can put a prybar in the yoke and force it past the spot and it rotates a little and locks again.
I had to get it off of the lift so I didn't get a chance to go further. Anyone got an educated guess as to what it is?

Re the thumping - did you check u-joints, transmission mount and/or motor mount condition when it was on the lift? Can't speak to the drive shaft lock up when spinning it counterclockwise so not sure if that's normal or not.

 

[Eman85]

Dropping the transfer case will probably be the next step when I can get to it. I've had a lot of these out and it will need the pump upgrade done to it anyway. I've got a friend with a good used TC if the hard parts too expensive it that's what it is.
U-joints have been replaced recently and they are in good condition. All mounts have been checked and fine. This locking isn't normal and the thumping is pretty violent if I let the wheels spin freely at idle. I had to slow the wheels with the brakes to be able to go under it and listen/feel the noise. . This is almost like a contest now to see who guesses right. So far 2 friends/shop owners and my mechanic from my shop all say transfer case.

 

[exp500]

TCase neutral will tell you alot.With wheels lifted.

 

[Eman85]

TCase neutral will tell you alot.With wheels lifted.

I don't believe a 97 with pushbuttons can be put in N.

 

[exp500]

Maybe this?

 

[Eman85]

Video doesn't work. All I've read says later models you can press 2wd and 4 hi button. Nothing lost I'll try it when I get a chance.

 

[Eman85]

For the record I pushed every combibation of buttons and held them, never got N in transfer case.
Did move it around today and found this. In 2wd forward in drive it makes noise and it also makes noise in reverse. Stopping at the high spot and allowing it to roll forward with transmission in neutral it doesn't make noise. Doing the same thing letting it roll backwards in neutral it does make noise.

 

[Eman85]

Pulled TC and opened it up, don't see anything out of the ordinary. Disassembled the rear completely found rough looking pinion bearings inner was the worst with a few galled rollers and the race was rough, outer had 1 bad looking roller. Complete bearing replacements and we see where it takes it.

 

[Eman85]

Before reassembling the transfer case I pulled the output shaft bearing and it felt like it had a rough spot so it got changed. I replaced every bearing in the differential, I cut the cages on the side bearings and although the races and rollers looked OK the inner races were galled badly. When putting the driveshaft in I didn't like the rear u-joint, it had a slight bind when pivoting past center. Pressed it out and it appeared the caps were too tight and the end of the cross was rubbing inside the cap. Put a new u-joint in. Test drive and noise is gone. Nothing like working on high mileage vehicles, now on to the front end needs ball joints.