drift a 944

I'm looking to buy a used LSD unit from a 1989 951S with 115k miles. It is just the LSD, no ring gear, no trans-cooler gear, nothing else attached. Would I still be able to use the speedo gear and trans-cooler gear from my open diff? I think the trans-cooler gear mounts differently on the LSD than the open diff, right? And of course, what is a good price for a unit like this?

Thanks!

Oddjob

The open diff cooler drive gear and the LSD cooler drive gear are not the same part, and not interchangeable. The LSD cooler drive gear is an expensive part to buy new, so that needs to be considered.

Speedo gear is the same.

The Turbo S diffs are worth more than the earlier diffs because it has the updated pressure cups and discs. Maybe $400-600 is a ballpark range.

drift a 944

Thank you for the info... Do you know where I can possibly find an LSD cooler drive gear?

Also, what makes the open diff trans cooler gear not usable on the LSD unit? Is it because the bolt heads will interfere once the bearing is pressed down on it? (Trying to think of how they are configured)

Price sounds good so far, anyone else agree or disagree?

Oddjob

Dealership (but $$$...).

Face of the open diff and LSD are not the same, so the drive gear center and bolt circle are not compatible.

North Coast Cab

I have a 951 cooler LSD tranny. PM if interested.

boost feen

One thing you need to consider when looking at used factory LSD units is if it doesnt include the axle flanges you will have to buy new ones or source used ones which will be very hard! The LSD factory units use larger different spline count axle flanges? The open diff and LSD do not interchange.

Oddjob

The difference in axle flanges is between N/A axles (088 409 355) and Turbo/S/S2 axles (016 409 355).

So if the spline count is different between the two part numbers, you will run into problems if installing a Turbo LSD unit into an N/A gearbox, or trying to install an N/A LSD into an S/S2/Turbo gearbox.

But looking at PET, it looks like the N/A LSD does supersede to the 951 LSD part number, so that would indicate they are interchangeable, and that the axle splines would also be interchangeable.

Not sure, I have never worked on an N/A trans, and only have S/S2/T/TS trans parts to look at, which are all compatible. I did install a Turbo LSD into an S2 Open Diff trans, and reused the original S2 axle flanges w/o issue.

drift a 944

Well I am swapping this into an 86 951 trans, which currently has open diff and cooler. So the axle flanges should still work fine if I read correctly, right?

I think my main concern is going to be finding a cooler drive gear that will work on the LSD.

Long shot: anyone happen to have one of those gears for sale?

Bri Bro

Make sure you get the gear for the LSD.
https://rennlist.com/forums/2778582-post26.html
I read that one can cut out the center of the none-LSD gear and attach what is left of it to the gear pump. The metal on the gear is VERY soft and you need to have it aligned exactly in the center of the hub.

I would add on an after market trany cooler with a pump and avoid all the problems of leaks in the 20 year old cooler loop and the LSD gear that is no longer sold by Porsche (it was a $300+ part).