Hello,
Have discovered a small leak from the rear diff and it seems comin from the pinion side
of the diff.
Has anyone changed the pinion oil seal? And do anyone know the genuine part number for that seal? Its a 2009 4.2 na xk

 

Yes, I replaced them when I converted to a Quaife LSD, C2S52518

 

Thanks jahummer

 

I’d also advise you replace the Timken bearings whilst it’s apart, 2 each of LM603012 and LM603049.

 

My first intetion was to change only the oil seal as it doesn’t need to take the diff apart. But I see your point jahummer if I was taking the diff apart I would offcourse change all the bearings. But what is the part number for the bearing after the oilseal? I could offcourse change that one while I’ll still there😊

 

Hey Nookat,
Many differentials use a pinion crush sleeve to set pinion bearing preload. The sleeve is a single use item, so generally needs to be replaced if the pinion flange is loosened - as is obviously required to R&R the pinion seal.
Here's a generic sleeve for the Ford/Lincoln 8" differential:
https://www.rockauto.com/en/catalog/...h+sleeve,11624

(I checked jag parts...didn't find jag part number for crush sleeve. Forum experts please chime in here...)

Some car differentials, and most German ones, use shim packs (vs crush sleeves) to set pinion preload. If shimmed preload is within specs, pinion seal replacement without complete disassembly may be possible)

Also, as JA advised: Reason for pinion oil seal failure is often pinion bearing wear. Bearing wear causes loss of preload, which allows pinion to move relative to seal, resulting in leakage.
It is possible to replace seal and reuse old pinion bearings with new crush sleeve, but most will simply replace bearings as well; ditto diff carrier bearings at the same time.
Finally, inspect the seal surface on the pinion flange, replace if grooved or

 

Here's an 8" (Lincoln LS) differential parts diagram:

https://www.bluespringsfordparts.com...--differential

The pinion bearing crush sleeve is #13 in diagram; pinion seal #14, pinion flange #1

(Jag parts lookup seems to show entire differential as an assembly; no internal parts breakdown. There are folks on this forum who know which Ford parts may interchange, etc. The Ford parts shown seem fairly cheap and readily available)

 

Hi hisport, thanks for sharing. I guess its the #7 on this exploded view of the Jag diff.

 

That's it, mate...#7

(You might want to do a quick forum search. Cambo, in particular, has posted some good info on '07 -'09 X150 differentials. Believe there may have been a change (to GKN?) of diff vendor in '09 model year, so may be worth doing some homework before ordering internal parts. Jag does show seals available for pinion and axle flanges)

Also, my limited experience is that - in most cases - you can reuse factory pinion depth shim (#13 in your diagram) IF you use OE bearings (eg, Timken) AND you replace before the rear end starts howling. Ditto diff case side bearing (#16,#17) shim (#22), if you're lucky. Diff case shim easy to verify/adjust with dial indicator (backlash and preload), but generally close to good with OE if ring and pinion are unworn.

(Forgive me if you already know all this stuff. Differentials are generally so trouble free these days that few folks have occasion to mess with them...)

 

Thanks😊