Disco Crown and Pinion on a P38a diff centre hybrid?

[Jazzman]

I have in the shed:

1X P38a rear diff with a 4 pin centre. Strong centre weak crown and pinion.

1X Disco Diff with broken cross pin and damaged centre gears. Strong crown wheel and pinion but weak centre.

I'd like to know if it is possible to fit the Disco crown wheel and pinion to the P38a 4 pin centre and bolt the effectively hybrid P38 Disco diff into my D2a.

I did a search on this but it brings up more about going the other way (putting Disco diff centre into a Defender housing) with lots of posts but no real answers. Just Defender people complaining about how bad their diffs are.

[Blknight.aus]

pure guess work but...

I think you can go the p38 center into a disco diff carrier with the disco crown wheel and pinion and then bolt the disco carrier in but not the other way around due to a difference in the mesh/alignment on the gear faces. You may need to shim and stack the center carrier bearings.

[Jazzman]

I've got nothing to loose pulling them both apart and having a go. If it is possible I'm surprised that it is not a common upgrade.

[Slunnie]

I think you will find the CW/P are not compatible despite being similar. The Crownwheel is a different thickness and the pinion has a different bearing setup. You will also find they have different flange offsets and the P38 hemisphere is bigger than the Rover one - A P38 diff assembly wont actually fit into a Rover axle housing

Rover type:

https://www.aulro.com/afvb/images/imported/2016/03/116.jpg

P38 type:

https://www.aulro.com/afvb/

[Jazzman]

I don't think I explained myself very well.


The bearing setup on the pinion and flange shouldn't make a difference as I'd be using the same casting from the Disco. But the bearings on the P38 centre could make a difference if they are different size. The thickness of the crown wheel would obviously make a difference but if there is enough adjustment I might be OK, or perhaps it can be shimmed.


I really only want the 4 pin centre from the P38 diff.... If it fits.





I think you will find the CW/P are not compatible despite being similar. The Crownwheel is a different thickness and the pinion has a different bearing setup. You will also find they have different flange offsets and the P38 hemisphere is bigger than the Rover one - A P38 diff assembly wont actually fit into a Rover axle housing

Rover type:

https://www.aulro.com/afvb/images/imported/2016/03/116.jpg

P38 type:

http://d8poad116lmh0.cloudfront.net/wp-content/uploads/sites/63/2015/02/05173455/diffgear-p38_4.11front.jpg

[Jazzman]

Doesn't work. The rover crown wheel hits the rover diff carrier when bolted to the P38 centre. Therefore there is also not enough adjustment to line the crown wheel and pinion up.

[ballbag]

Thanks for the info.

[Slunnie]

Doesn't work. The rover crown wheel hits the rover diff carrier when bolted to the P38 centre. Therefore there is also not enough adjustment to line the crown wheel and pinion up.

I don't think I explained myself very well. :D You may need an aftermarket option for this. I'm pretty sure Jack McNamara differentials make a hemisphere like what you're doing but to suit a Rover diff.... but then again if you were going to that much effort you'd probably put a diff in to giver better drive like a locker, LSD, Torsen etc.
http://www.mcnamaradiffs.com.au/products.html

[Roverlord off road spares]

You guys with Hybrids, need to make up a list of parts you put in.
Makes it hard for us parts people when Bitzas require stuff.
I remember one member who I won't name ;) said he has a part X on the front diff and bought a part only to return it to say it was part B, only to return it to repurchase part X as the front and rear diff were different from different vehicles.:o