After I go more than 10 or 15 miles at highway speeds, I get this groaning/creaking noise from the rear end (suspension? half-shafts?) when I turn or accelerate from a stop. Never happens unless I've driven a while at 50mph or more, and only happens when I turn or start out. Iif the car sits for a while, no noise. Ring any bells with anyone?

JB

'78SA

 

Sounds like the limited slip differential. GM sells an additive that will stop the clutches from binding and making that noise. On my car it took a few weeks for most of the noise to go away. It hardly ever happens now

I went ahead and changed the oil at the same time. It was one of those 20 minute jobs that ended up taking 4 hours and making a big mess :(

If a lube shop will do for you at a reasonable cost, I would recommend it ;)

~Jay

 

Your posi unit housing has probably started to elongate the pin hole throught the posi unit housing (Very Common) That why it's fine when it's cold and the oil is thickest. But you drive for awhile over 50 mph and the pin actually wedges off center in the housing. That is the bad sound you get when you slow and do tight turns like in a parking lot. No amount of posi lube will fix that. It's also a bigger problem if you ever had a Auborne Gear posi unit installed

One good thing is. If you have a lower powered car it could last for years! ;)