Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!
1 - 11 of 11 Posts

·
Registered
Joined
·
172 Posts
Discussion Starter · #1 · (Edited)
Noticed it during an oil change. Significant amount of rotational play, but locks into place after turning it clockwise (facing front).

This is also accompanied by an occasional clunk and hard downshift from 3rd to 2nd. (Sounds like the driveshaft)

I’m still nailing down symptoms, appears only have play after being in Drive. Does not budge if the truck was in reverse.

Transfer case was last opened 8k miles ago for a pump rub kit. No issues inside at the time, but I’ve used all 500+ hp several times since then. No fault codes.

Where should I look next? I think something is worn inside the transfer case. I want to get ahead of this before something breaks. I’ll add a video when I get a chance.
 

·
Registered
Joined
·
4,193 Posts
This is the driveshaft to the read diff or front diff?
 

·
Registered
Joined
·
172 Posts
Discussion Starter · #3 ·
Rear shaft
 

·
Registered
Joined
·
172 Posts
Discussion Starter · #4 ·
Looks like the slip yoke is working it’s way out?
Sensitive content, not recommended for those under 18 Show Content
1090251
 

·
Registered
Joined
·
4,193 Posts
The driveshaft does move in and out of the trans tailpiece. That's normal. The rear diff moves forward and backward as you drive pushing the driveshaft into and out of the tail shaft. . Whether yours moves way more than normal, I don't know. But you definitely have something wrong with your truck and from your description, I don't think it's the slip yoke. Of course, you could pull your driveshaft and see if there's something that looks bad there, and how much more spline length you have inside the tail shaft. If your truck is lifted, that could add to the problem, but many people have lifted trucks without the problem you describe.
 

·
Registered
Joined
·
172 Posts
Discussion Starter · #6 ·
Thanks Ron. Truck isn’t lifted but I am on 285/75/16. Actually I forgot I recently had a long drive at gvwr, which would explain the slip yoke looking like that.

I think I’ll have to crack open the transfer case to get to the bottom of the issue.

The problem didn’t show up today, but I’ll keep checking and post a video when it does again.
 

·
Registered
Joined
·
172 Posts
Discussion Starter · #7 ·

·
Registered
Joined
·
39 Posts
The rotation looks ok. I would pull the driveshaft and grease the slip yoke splines. That will help with the clunk noise.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
4,193 Posts
In a video, it's hard to tell whether the noise is from the pinion/ring gear clearance, or the parking pawl, or something else, maybe transfer case. But I'm sure you know where it comes from. That rotation doesn't bother me, but you describe
This is also accompanied by an occasional clunk and hard downshift from 3rd to 2nd. (Sounds like the driveshaft). I’m still nailing down symptoms, appears only have play after being in Drive. Does not budge if the truck was in reverse.
That's what I would be concerned about. It could be trans or possibly TC or ??
 

·
Registered
Joined
·
172 Posts
Discussion Starter · #10 ·
Thanks fellas. Noise sounds like tcase but I need to spend some more time down there to find it. I’ll pull the driveshaft this weekend and grease the splines to see if that helps.

If it’s the trans, my builder recommended I put in a few tubes of lube guard to quiet it down.
 

·
Registered
Joined
·
172 Posts
Discussion Starter · #11 ·
Using a stethoscope I believe the sound is coming from the transmission. Loudest towards the front of the pan (flat surface and full of fluid, makes sense it’d be louder there)

I want to say it’s the parking pawl, but I get the same noise from 3-2. I’m going to double drain and fill with Mobil delvac 1 (dex/merc in there now), then add lube guard if the clunking/ hard downshifts continue.

I only have 8k on the built trans with a lifetime warranty. I trust the builder but I’m a few thousand miles away from that shop right now. Thanks for the advice guys. I’ll grease the slip yoke this weekend for good measure.
 
1 - 11 of 11 Posts
Top