Differential Back Lash
Thread Starter
Intermediate
Joined: Feb 2019
Posts: 38
Likes: 2
Differential Back Lash
I am new to Corvette Forum and have a question about differential back lash. I am the proud owner of a 1994 C4 that just rolled over the 48,000 mile mark. While driving on a mountain road the other day I noticed some back lash in the differential. My question is, how much back lash is normal? if any?
Le Mans Master
Joined: Sep 2013
Posts: 6,192
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From: near the thumb in the mitten
There's always some backlash or play between gears. Ring gear back lash is .005 -.009 in street driven applications. You maybe feeling driveline slack, which is all the play between gears from the transmission to rear tires. You could drive and half shafts, mounts and c beam. Mostly to make sure nothing is worn or loose.
Melting Slicks
Joined: Nov 2013
Posts: 3,451
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From: Greater Cincinnati Area.
If the car is a 48K auto, it would be unusual to have problems there this early. As Kevova says, there's many other places for movement or wear than the diff. Ujoints, particularly.Two notable exceptions to the above is if the diff leaks or has water introduced to it. Then you can absolutely have problems in a low mileage vehicle. You should probably check/change the fluid, and if it the level is fine, grab a wheel and rock it with the car in park (Or, even better, have a friend to it) and chase down your slop then.
As far as an exact amount, this measurement in thousandths is taken with a dial indicator on the ring gear during setup. In practical application, assembled and in the car, the yolk should "rattle" back and forth a minimal amount.. Maybe a 32nd of a turn. There is always some movement there, it should have movement and that is normal. Too much and you usually have bearing noise associated with it and it is obvious something is wrong.
Last edited by confab; Mar 27, 2019 at 10:03 PM.
Thread Starter
Intermediate
Joined: Feb 2019
Posts: 38
Likes: 2
Differential Backlash
Thanks for the feed back. It may not be "backlash" that I am experiencing. I had my Chevy dealer check it out and they could not find anything out of the ordinary. Oil looked good, no water or metal. However, there is a definite "clunk" after you de-accelerate and then accelerate as you come out of a curve. Never have experienced that with any of my previous cars. Thanks again, Jabohaz
Last edited by jabohaz; Mar 28, 2019 at 08:55 PM.
