scottjamison

Hi,

I have my new diff and I need to break it in. Ideally I would lift the car on my QuickJack and then put jack stands under each trailing arm to lift them horizontal and run it for a few minutes in fwd then rev.
I have not tried starting the car while on the QuickJack. While it is WAY more stable than being on jackstands, has anyone done this and have any learnings?

I figure I will use the lower stop on the QuickJack just to be safe(er).

Scott

BKbroiler

This doesn't answer your question, but I am rebuilding my rear now, including a new ring and pinion, and I have a Quickjack. I will do the break in with the car on the road. I have done this several times over the years with no problems.

wwiiavfan

Sorry for asking a dumb question, but wouldn’t you want to break in a new rear end under load, so you get a good wear pattern started on the teeth?

Torqued Off

I have read more than one post that you should not run a car with the trailing arms fully down, i.e. the half shaft angles are such they can bind. Secondly, I think the idea of "breaking in" a differential is over-thinking. I could be wrong for sure,.....but just drive it, do some figure eights, and forget about it. Did GM have any "break in" procedures on new C3 Corvettes?

suprkoop

I did, but the jack flew out from under the nose after the first bump....

Mr D.

Quick answer ---> DO NOT do that.

scottjamison

I hear you. I was surprised when the directions were to do it this way just to heat up the parts and let them cool. Then drive it. I agree that I am not really comfortable about it, so I am going to call them back today and talk to them.

Haggisbash

Motive ring and pinion paperwork says to break them in for the first 500 miles and I quote - Light driving for a period of 500 miles and not at a constant road speed (50 - 60 mph) for any ratios lower than 3.73 No towing for extended periods.

terry82

i agree dont do it.

Haggisbash

When I first got my vette, I happened to run it with the rear on jackstands and there was no binding or noises coming from the rear, yes the trailing arms are at their biggest angle in comparison to the diff but no different than say if you travelled quickly over a hump back bridge. Now of course I have read all the posts about not doing this so haven't repeated the execise but still see no harm in it for a short trial at low speed assuming the drivetrain is in good condition.

resdoggie

But there could be harm doing it and that's why no one recommends it.

scottjamison

Any change for 3.73? That's what mine is.