Hi All - my 99 XJR has been at the dealer for a week or so now as they try to decide how best to address a minor (?) fluid leak from the diff.

They are trying to address the issue in the least costly way possible as:

a) They don't want to have to tear the diff apart
b) They don't want to order un-necessary and expensive parts

Do any of the techs out there have some sage advice to offer on this sort of thing?

 

Where, from the diff, is the leak?

 

Hi all,
Honza1, you are scaring me! My 03 XJR is suffering from the same problem. My leak is from the pinion seal. It went in for repair yesterday, hopefully will be done today. My research on this issue led me to believe that the parts were relatively reasonably priced. The differential fluid is quite pricey though. The labor is also quite steep.
This seems to be a pretty straight forward repair. ==> Shouldn't be a big mystery for a decent mechanic with the proper tools. If I'm wrong, someone will jump in and straighten this all out.

Thanks.

 

This is not an easy repair, and the bulliten for this for 1998 vanden plas was nutz. They have a torque figure of 150ft lb. This crushed the pinion bearings together and now the leak is worse. Should have done it the way my S-10 Chevy was done with taking torque figure to rotate the pinion and gone from there. This SUCKS. Thing is that when I called the dealer mechanics (not the service manager) they told me that they don't do many (horse $%$#) and that the bulletin would be the way to go. That is one heck of a lot of force and now I am really screwed. Any body got any ideas?

 

Oh and there was no crush sleeve. It was a spacer. Now I feel that it is a crush sleeve.

 

If there is a crush sleeve in there and you want to pull the pinion flange off on any normal car, I use an impact and snug it down until I think it is good. There is no way to check pinion preload with the differential assembled. If the crush sleeve has already been crushed to specs, you only need to tighten the pinion nut enough to contact the already crushed sleeve. An over-crushed sleeve will result in incorrect pinion depths and preload and will lead to early differential failure. Locktite and careful tightening with an impact is probably the easiest way to go and I have been doing it for years. If there is a solid spacer, torquing to specs with locktite is the way to go. Where is this bulletin everyone is talking about?

 

I just ordered one of the pinion seals from ebay that doesnt come with the pinion flange and nut. That alone was $69....ridiculous! It does beat the $350 or so for the pinion flange, seal, and nut kit. Let's hope it works. Is there anywhere cheaper to get the whole kit? Thanks in advance.

 

The first thing to check is the case breather!!!! (JLM20323) I keep one in stock.

Be aware that about half the time I change a pinion seal flange kit I find that the Diff case breather on the top of the case is BLOCKED!!! The new one will leak because the pressure buildup will force oil out of the new seal or an output flange seal. (somethins gotta give!) Use a 'shorty' 14mm spanner to remove it for testing (yes with your mouth) be sure to spit alot afterward!!!

I check the breather first and if it is faulty/clogged I replace it, fill the diff and clean the pinion seal area.

Send the customer on his/her way and tell them to come back in a week or two.

If any seals are wet again then the replacement is recommended.

The best way for a person to replace the pinion seal is to buy the flange seal kit and mark the old nut and pinion shaft. Remove the nut and replace the flange seal. Reinstall the original nut and put it back where it was. If the flange has the same dimensions as the original, then the preload will be the same.

I know all this because I blindly followed the TSB and the car came back leaking from the output shaft seal after the pinion seal kit. When I pulled the output shaft, I heard a vacuum sucking/pop when it was pulled from the case. I removed the breather and it was blocked!!! I replaced the breather and reinstalled the axle shaft. NO MORE LEAKS!!!!!!!!!!!!!!!!!!!!!!!

Since then I have checked the breather FIRST and found several to be faulty.

Here is the TSB and one for the tools

bob gauff

 

Well snap! I wish I would have known to check that first I am pulling this baby in the morning to see if its clogged. I dont think I have a 14mm spanner. Maybe I can find something that will fit it.

 

You are the man!!! I pulled the vent plug this morning and viola! I heard a sucking or blowing sound when I had it almost all the way out. I couldnt blow through it. I was going to put a hose barb in there with like 6" of hose, but it wouldnt clear the body. So I took this one apart and cleaned it. There is just a rubber disc and a spring under the cap. After cleaning it I can blow through it So once again I have to say it....you are the man!! Thanks so much. Lets hope the seal is all good now

 

An update to my prior post: I had contacted a Jaguar Mechanic on line about my diff leak and the leak after. As most of us know the flange acts as a press to press the seal into the diff case. The stamped steel flang can bend to be cone shapped rather than press the seal in. Though I rotated the shaft while tightening it may not have pressed it in and therefore the seal surface is not mating properly.

To ixj8it The kit is important. I did the same that you did with seal without sleeve or nut and wound up buying the kit anyway as the race of the sleeve was baddly worn as it is only stamped steel. AS far as the crush sleeve this diff doesn't have one. It is a spacer that is not supposed to crush. This still may have happened. Hope it didn't and the seal not seating is the cause. Oh and this is not like most of the diffs I have done. I really don't like the stamped steel bearing surface. One of the Toyota's I did I just marked the place for the nut and tightened to there and staked it. Worked for years.

To motorcarman: Will check the breather as this might be the reason it was leaking. Unfortunately when you remove the pinion sleeve from this unit is pretty much does the seal in due to the stamped steel mating surface.

 

To ixj8it. The way to separate the drive shaft from the diff pinion flange is to remove the center 4 mount bolts. Do not let hang as the transmission end has a rubber isolator that the shaft bolts too and won't bend down enough without putting pressure on the trans seal. Have to support it.

 

Could you possibly measure the thread for me?

 

I think the original installed vent is 10mm X 1.00mm but the replacement measures 28G on my metric thread pitch gauge.

It seems like the original vent unscrews evenly all the way out but the replacement has a pipe taper thread and gets tight only partway into the hole.

bob gauff

 

Thanks for that.

Is the OD on the replacement still 10mm?

... um what does 28G mean?

 

I think that G is the Whitworth size and 28 is the pitch.

bob gauff

 

As a belated followup, found on some forum:

M10x1.0 has a thread pitch of 25.4 tpi
1/8 NPT has a thread pitch of 27 tpi
1/8 BSP has a thread pitch of 28 tpi

 

Mr. Motorcarman thank you, your willingness to share your knowledge is greatly appreciated.

 

Update on mine. I had a seal that I bought thinking I might not need to replace the hub and nut. When the hub seal bearing surface was found to be too worn I bought the kit. After doing the repair to the bulletin specs I still had a leak. Took it to a reluctant local mechanic and asked him to take off the new hub and use the extra seal if possible. He pulled it apart to find that the seal did not go all the way into the diff housing and actually made the seal cone shaped. Had the breather checked and that was clear. The pressed on steel sleeve had to be altered as was bent up. He put it back together and thankfully still holding. Not sure why it stopped driving in but this should not have happened. Fluke. Alls well!

 

Thanks! Great advice. I have also, owned Jags since 70's and have done most repairs myself..Now I have '98 xj8 and 2000 xj8 vandenplas.
So, I probably need your info.
Sounds like a good item for normal maintenance check.
Where exactly is breather located?
b. lewis