Is this behaviour correct?

[Donker]

Put my Coupé on the lift yesterday to see if I could find my transmission problem, and I was just wondering if this is how it should behave:

When you spin one of the front wheels the other one spins in the same direction, not the opposite as I thought it would? Also, when I put it in gear and drove it, and touched the brakes lightly, the front wheels stop and the rear wheels spin.

When I turned the steeringwheel left, the jerking starts, like a bad cog or splines or something.

What do you reckon? CV joint or am I about to embark on a gearbox change?

She's a 3b Coupé 1991

[S2central.net]

Front diff is OPEN, so you should see wheels spinning in opposite direction when you do this on the lift - BTDT.

You'll see the same at the rear unless you have the difflock activated of course.

I've never tried any brake tests with the wheels running up on a lift - there might be weird behaviour just cos of what Torsen centre tries to do in that unnatural scenario.

I think you have problem inside the gearbox - with front differential I would say - would explain horrible noises when turning the steering wheel. But then I might be confused - do you hear these noises when driving or just up on the ramps with the car running ingear ?

If the noises are on the ramps then you should be able to isolate the source of noise from a CV joint to the actual gearbox.

Paul

[prosty]

Sounds like front diff problems. I have one in "stock" if you need it

[Donker]

Paul: It's sort of like something misses a cog, loosing drive for a moment then a big bang when it kicks in again. Both when driving and on the lift. But on the lift I could only make it happen when turning left, when driving it sometimes occurs straight forward as well.

I'm almost certain that it's in the box, but I'm going to tear the CV apart to check to make sure it's whole before I do anything else.

Thanks Prosty, I'll have that in mind!

[Donker]

I've started taking the car apart now.

I turned the transmission with a wrench in the hub centre bolt, and it certainly feels and sounds like a cog gone blunt. Going to empty out the gearbox oil next, and see if any bits fall out.

I'm looking at alternatives now, with a used gearbox as the most likely. Can you change the front diff only in the gearbox? Or is it a pain?

On the upside, my propshaft looks mint, and the support bearing looks ok as well.

[Donker]

Right. Drained the oil and this came out:



No big surprise I suppose. Will be trying to get my hands on a new 5-speed box as I can't really motivate a 6-speed conversion right now, the car being all stock as it is.