Differential: groans in reverse.....?

[flipittothewall]

Anyone ever have a problem like this? About 1 out of 9 times that I back up my backend "groans" like an old man for a few feet. I've changed my diff oil during servicing, and found no metal shavings or gunk just normal condition 90W. Haven't gotten to opening it up to look at it nor tear it apart (don't want to have to...). Any ideas/input?

'90 240 on hiatus.....Daddy's playin in da Big Sand

[s86d]

no idea... most cars in reverse sound like rc cars (that cool elecric whine they make) but i thought that was normal...

[flipittothewall]

Yeah, I know about that....but this is an outright grrrroooaaaan. Sounds like an old oak door on bad hinges opening.

[NISTECH]

sure its not your brakes groaning?

[matchstyc]

I asked this same question on here a few months back and after a while I figured out it ws my brakes. Not my diff. When it starts to groan tap the brakes just enough to not slow the car down at all. If the groaning stops for a second, it's the brakes. It seems to be common with our rear brakes for some reason.

[rco8786]

Ya it's pretty normal i know a ton of people's cars that do it...mine did it as well until i swapped an lsd in.

s86d: the reason for the whine is b/c reverse gears arent spider gears(i think thats the name) so they engage each tooth all at once and make some cool noises.

[s86d]

rco thanks for that little bit and yes they are cool noises

[allthrottlenobottle]

mine used to groan in reverse and it turned out to be one of my struts was gone. Replaced it and it stopped.

[flipittothewall]

Well, that could be it (the brakes)....haven't gotten to adjusting or replacing those yet, but it's on the 'do-it-now' list anyhow upon my return from Icrap. Come to think of it Matchstyc, I got frustrated once and smacked the brakes on....it did stop. Thanks everyone.