Rear end drop when accelerating

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

98_k1500

strange noises are normal
Joined
Jan 21, 2014
Messages
3,927
Reaction score
78
Location
Starkville, MS
Trucks do it too, people just don't complain enough about them to do anything about it.
 

Zanter22

Newbie
Joined
Aug 25, 2014
Messages
22
Reaction score
0
This may be interesting for Tahoe/Yukon owners.

http://www.tahoeyukonforum.com/forum/showthread.php?t=38275


There is apparently a nickel plated slip yoke that eliminates this on these trucks. Why it doesn't do it on pickups - I have no idea... But after doing a lot of reading through TahoeYukonForum.com I've seen where many people have addressed this.
What you may try doing is pulling the drive shaft, grease the inside of the yoke and put it back on - see if that eliminates the problem. Not a permanent fix but it may at least help you figure out where the noise is coming from. I know I've read somewhere also that someone drilled a small hole and put a zerk fitting on the yoke and greased it from time to time to eliminate the problem...
Mine does the exact same thing and it drives me nuts.
I think you got it spot on with it being a slip yoke problem. Seems to be a decently common problem. The part number for the nickel plated slip yoke is 12477702 from what I've read.
 

haroldwca

Newbie
Joined
Jan 25, 2020
Messages
36
Reaction score
41
Location
Southeastern NC
I hope no one minds that I'm posting on a 5-year-old thread, but this is exactly what I'm experiencing with my truck - when I accelerate from a stop, I hear a clunk from the rear differential. Today I took the cover off the diff to examine what was happening. With the rear on jack stands and the trans in neutral, I rotated the drive shaft while examining the differential. The spider gears showed a significant amount of slack. I double-checked the slack by rotating one wheel by hand. I could move the wheel about 1/2 inch by the circumference before the other wheel moved. I observed the slack being taken up in the movement of the spider gears. The axle gear of the wheel that I rotated moved instantly. It transmitted the movement to the cross-shaft gears, then to the other axle's side gear with a noticeable, incremental delay. I could see the slack being taken up. Although I have been around vehicles all my life, and have substantial experience in almost every aspect of vehicle restoration, I have to admit that I am a novice with differentials. Can someone confirm that the amount of slack I just described is evidence of significant wear?
 

Tavi

Vehicle enthusiasts
Joined
Apr 11, 2013
Messages
301
Reaction score
161
Location
North east NM
I hope no one minds that I'm posting on a 5-year-old thread, but this is exactly what I'm experiencing with my truck - when I accelerate from a stop, I hear a clunk from the rear differential. Today I took the cover off the diff to examine what was happening. With the rear on jack stands and the trans in neutral, I rotated the drive shaft while examining the differential. The spider gears showed a significant amount of slack. I double-checked the slack by rotating one wheel by hand. I could move the wheel about 1/2 inch by the circumference before the other wheel moved. I observed the slack being taken up in the movement of the spider gears. The axle gear of the wheel that I rotated moved instantly. It transmitted the movement to the cross-shaft gears, then to the other axle's side gear with a noticeable, incremental delay. I could see the slack being taken up. Although I have been around vehicles all my life, and have substantial experience in almost every aspect of vehicle restoration, I have to admit that I am a novice with differentials. Can someone confirm that the amount of slack I just described is evidence of significant wear?
Yes. Very likely the cross shaft mentioned in previous posts.
 

CW73

Newbie
Joined
Oct 25, 2019
Messages
20
Reaction score
8
Location
Clyde Tx
This may be interesting for Tahoe/Yukon owners.

http://www.tahoeyukonforum.com/forum/showthread.php?t=38275


There is apparently a nickel plated slip yoke that eliminates this on these trucks. Why it doesn't do it on pickups - I have no idea... But after doing a lot of reading through TahoeYukonForum.com I've seen where many people have addressed this.
What you may try doing is pulling the drive shaft, grease the inside of the yoke and put it back on - see if that eliminates the problem. Not a permanent fix but it may at least help you figure out where the noise is coming from. I know I've read somewhere also that someone drilled a small hole and put a zerk fitting on the yoke and greased it from time to time to eliminate the problem...
Mine does the exact same thing and it drives me nuts.

I've delt with this many many times... Pull the drive shaft and grease the YOLK with Motorcraft XG-8 grease.
You must be registered for see images attach

Motorcraft Ptfe Lubricant Xg-8 Grease
 

CW73

Newbie
Joined
Oct 25, 2019
Messages
20
Reaction score
8
Location
Clyde Tx
I should have mentioned that I pulled the cross shaft out and examined it as well. It did look pristine. I could not see any evidence of wear.

If its rear end clunk when putting vehicle in gear it most likely would be excessive ring & pinion backlash. If its after stopping and then accelerating and you feel a jolt its usually the slip yolk binding.
 
Top