Citroen XM Forum

The differential oil is under a ot of stress and keeps the gears and bearings from wearing.
My advice would be to change it.

good point

how involved is it to change?

The 4HP18 differential not a separate unit and it runs in Dextron 2 transmission fluid. The differential housing is open to the main gear set but fluid is also fed into the diff via the regulator.
There is a drain plug on the bottom of the diff housing to help remove any fluid held behind the weir between the diff and main case.
I think the 4HP22 may have a separate differential but not sure.

D

Honestly I’m thinking it’s probably best I just leave it alone haha

It works as is, I’ll only break something

just over 5,000 miles covered now in this car

i cannot express just how well she drives

okay i've figured out the idle now

it does warm idle on a cold start and cold idle when it's warm.....

or at least that's how it looks

That would have to be the waxstat cable on the rear of the pump is pulling in the wrong direction.
The lever pushes the accelerator linkage, so unless somehow built up incorrectly it can't operate in reverse.
Try disconnecting the cable and set the warm idle only.

The waxstat cable on the front of hte pump is cold start timing advance.
With the engine running pull the lever to the right, then relax it and you should feel the mechanism vibrate as it comes back into contact with the cam ring.

interestingly the cable on the rear of the pump ( in situ) wasn't connected and looked as though it was snapped, due to that i decided to omit installing the little spring

it idles down to around 1,000 rpm in drive however, so i'm not overly bothered about that, if anything it makes driving in traffic much easier as i have a much more useable "creep" speed

i will get round to sorting it at some point, but no rush, i must admit she's running absolutely great, no smoke, mega economy and lots of power

regarding a previous post about ride height

this is normal running height, just after parking up today after a 40 odd mile round trip

also question, yesterday i unfortunately drove off before she had risen and caught something underneath on a bump in the road with a loud bang, my fault....i was rushing a bit and thought i was in the C5 for a moment!

That still looks a bit high to me, but really you need the car on flat ground and the engine running to check.

The lowest part is the exhaust, so that is what you will have scraped.

Regarding the pump idle setup, fit any springs, otherwise the levers may flop around affecting setup.