reefdiver550

Going to be changing all the fluids in a newly acquired CTT. Going with the Castrol 75w-90 in the front differential, REVENOL in the transfer case. But I'm at a loss for the rear differential.

What fluid have people been using in the rear differential with PTV+?

deilenberger

It depends on what model you have. The 955/957 is different from the 958 cars (which have their own subforum..) What year is your newly acquired CTT?

"Better questions get better answers" - Me.

reefdiver550

My apologies...its a 2011.

I was searching all over the 958 subforum and did mean to post this question in there.

deilenberger

I'll move it over.

There is a specific oil for PTV rear differentials.. I suspect it has a slip additive allowing for some slip under normal use. You may want to check with Porsche for the PN, then try Googling it to see if a cross-reference shows up. I believe in one of the threads someone had done that, but apparently your search didn't turn it up.

reefdiver550

The Porsche part number is 043-300-37 ($82.24) The only alternative that Pelican had was Motul. I was just inquiring as to if others had tried that or anything else with success.

deilenberger

http://lmgtfy.com/?q=043-300-37

Note the first return..

reefdiver550

Yea I saw that...but its definitely the part they were going to order and is available all over the place.

F1CrazyDriver

bump.
I'd like to change my rear differential fluid over the long weekend.
Possible to use 75-90 Mobil 1 synthetic stuff on a PTV + ?

deilenberger

I would say a qualified no. Dunno if the "synthetic stuff" is made for a limited slip differential. If it is - it's "probably" OK. The PTV differential has a computer controlled clutch in it - multiplate type. It ties the two axles together. On sharp turns it has to allow some slippage. Limited slip diffs often work with a similar clutch assembly. If the oil doesn't allow some clutch slippage - the plates in the clutch will lock and release when you make a sharp turn, causing a noise like running over walnut shells. The fix for that is the correct oil, or adding a limited slip additive (GM makes one for the Corvette) to the oil.

So that's my qualified NO. You haven't given us enough info (like a link to the Mobil-1 oil you were thinking of using) to make a rational YES/NO decision.

If it was me - I'd just mail order the "right stuff" (ie - Porsche juice) and do it. How many times do you expect to change this fluid? It's not a major expense difference in the long term to go with the right stuff - and it might present a significant savings if using the wrong stuff causes some damage to the driveline.

YMMV,

F1CrazyDriver

good point.
i called my local dealership this morning and they do not sell by the qrt.They have a drum full of the stuff in the back.
that means i don't get to do it this weekend as i have to order.
He did mention it's in fact 75-90 however he's not sure if it had additives or make of fluid

the head

I went with Ravenol MDL. The part number crosses over to the Porsche part number for the carbon disc PTV rear diff. $20/qt on Amazon

TRM04

Dion Houng-Lee

Just sharing my experience but I went with the Ravensol and it lasted a couple months without the walnut crunch on left turns and now it’s back. Switching to the Porsche lube this weekend.

garrett376

Motul 300LS works well.

skinnytirez

you have the PTV+ ?

also, how many miles do you have with the Motul fluid?

Any noticeable differences? We’re you experiencing any issues before? Or just preventative?

Thanks!