P38A Front diff pinion wobble?

So I am a bit confused. I'll describe all the symptoms and what I think about it, but would like a bit of input and other opinions.

So I had a leaking front diff. Leak came from the pinion seal. I replaced the seal. It nearly immediately leaked again. The leak is a very slow leak, but you can see oil get thrown around in that area.

I also have a very irritating vibration between 95kph and 105kph. Feels like imbalance in the wheels. Only you don't feel it in the steering wheel, just in the seats. I already checked for play in the u-joints on the props but nothing.

Now how can a new seal of good quality (no Britpart) which was installed correctly and with care leak again immediately? Combined with the vibration I have I am thinking that there may be some play on the output bearing on the pinion shaft of the front diff and as the shaft wobbles it deforms the seal allowing oil to leak out. Is this possible? What do you guys think?

If the diff flange is worn then the seal won't seal against it. Also the seal is different depending on what mud shield your flange has.
I am presuming the diff is the same as a Defender, if not ignore me.

The vibration could be that your front driveshaft is not phased correctly. The u-joints need to be installed slightly out of phase.

Could also be pinion carrier bearings, can you feel any play in the pinion when jerking it around by hand?

The oil leaking could be a bad/worn sealing surface on the pinion itself. Have you tried installing the seal at a slightly diffrent depth if possible so it rides on a slightly "fresher" spot on the pinion. Edit-not the sealing surface on the pinion, the sealing surface on the drive flange

The P38 has wolf diffs.

As above.

My rear one has started leaking so I am going to have to do the same job. At the risk of hijacking the thread, on tightening back up does it have a sort of crushable washer or do you just mark everything up and tighten until the marks all align again?

Grrrrrr said:

As above.

My rear one has started leaking so I am going to have to do the same job. At the risk of hijacking the thread, on tightening back up does it have a sort of crushable washer or do you just mark everything up and tighten until the marks all align again?

Click to expand...

I just Mark them up and tighten back to that spot
Check the surface and check for play, I've seen two 2000my with failed bearings in the nose

Thanks all!

The pinion flange sealing face seemed okay to me when I did the seal. But installing the seal a bit deeper may be a good idea.

Also worth mentioning the car has 275k kms on the clock.

How can the u-joints be out of phase? I did take the drive shaft out but didn't touch the u-joints. Seemed all original to me.

Grrrrrr said:

As above.

My rear one has started leaking so I am going to have to do the same job. At the risk of hijacking the thread, on tightening back up does it have a sort of crushable washer or do you just mark everything up and tighten until the marks all align again?

Click to expand...

You have either a nut or a bolt holding the pinion flange on. The nut needs 135Nm, the bolt 100Nm. But mark the prop shaft flanges to help getting it back together.

If you've also worn a groove in your flange where the seal runs, I've had good results using on of these to renew the surface...

Speedi Sleeve

Here is the row about driveshaft phasing. Wammers at his finest, enjoy...


You can't change it, but original LR driveshafts have the UJ's at slightly different rotational angles to each other from one end to the other to reduce vibration. Some aftermarket replacements don't have this.

OK, cat among the pigeons...
My 99my front prop is straight with matching positions on the uj's.
My son's 2000my front prop is phased

Mark Piercy said:

OK, cat among the pigeons...
My 99my front prop is straight with matching positions on the uj's.
My son's 2000my front prop is phased

Click to expand...

It came down to how you define “phased” in the end…..


It obviously doesn’t make much difference. P38s have happily been trundling along with both for ages!

I know what your saying. My sons does have a vibration at around 70 so what I might do is drop the prop and see if it can be changed to phased or not. It may not be possible but I'll find out.

Mark Piercy said:

OK, cat among the pigeons...
My 99my front prop is straight with matching positions on the uj's.
My son's 2000my front prop is phased

Click to expand...

Bah. Aftermarket rubbish!

From quite a number of hours of research on the proshaft phasing topic:

In phase being where the u joints line up with each other like the rear driveshaft does.

-All genuine LR front driveshafts for the P38 have the u joints set slightly out of phase (i think its like 2 teeth on the slip joint).

-This was done because of offroad height in the air suspension. In order to not have u joints bind up when at offroad height and full droop they rotated the whole front diff so that the pinion points slightly up at the transfercase. Now because the transfercase u joints and diff u joint are not parrellel when at highway height or any height for that matter you get driveshaft vibrations because the joints dont cancel each other out anymore. So to solve this vibration issue(obviously most noticeable at high speed) they set the front u joints slightly out of phase. Now because the pinion is pointed up and the u joints are out of phase the acceleration and deceleration pulses of the two u joints now match and cancel each other out.

-I have not seen a aftermarket driveshaft that is phased correctly for a p38

-Some people claim that you cannot install the the slip joint on the front shaft incorrectly but ive found you can. When i got my p38 i spent hours trying to find a vibration at around 105kph. Turns out the front shaft was not phased correctly. Reinstalling the slipjoint in the correct position fixed it and another vibration i thought was my tyres at around 68kph.

-How should they be installed? On the driveshaft side of the slip joint there is a missing tooth, on the u joint side there is a little nub, just line these two up when installing the slip joint.

Heres a picture of the little nub i got from rangerovers.net


-This is unverified but i think the classics that have air suspension came with the slightly out of phase driveshafts too, same as all the P38s

Where were you 10 years ago!!

FEI said:

From quite a number of hours of research on the proshaft phasing topic:

In phase being where the u joints line up with each other like the rear driveshaft does.

-All genuine LR front driveshafts for the P38 have the u joints set slightly out of phase (i think its like 2 teeth on the slip joint).

-This was done because of offroad height in the air suspension. In order to not have u joints bind up when at offroad height and full droop they rotated the whole front diff so that the pinion points slightly up at the transfercase. Now because the transfercase u joints and diff u joint are not parrellel when at highway height or any height for that matter you get driveshaft vibrations because the joints dont cancel each other out anymore. So to solve this vibration issue(obviously most noticeable at high speed) they set the front u joints slightly out of phase. Now because the pinion is pointed up and the u joints are out of phase the acceleration and deceleration pulses of the two u joints now match and cancel each other out.

-I have not seen a aftermarket driveshaft that is phased correctly for a p38

-Some people claim that you cannot install the the slip joint on the front shaft incorrectly but ive found you can. When i got my p38 i spent hours trying to find a vibration at around 105kph. Turns out the front shaft was not phased correctly. Reinstalling the slipjoint in the correct position fixed it and another vibration i thought was my tyres at around 68kph.

-How should they be installed? On the driveshaft side of the slip joint there is a missing tooth, on the u joint side there is a little nub, just line these two up when installing the slip joint.

Heres a picture of the little nub i got from rangerovers.net
View attachment 336700

-This is unverified but i think the classics that have air suspension came with the slightly out of phase driveshafts too, same as all the P38s

Click to expand...

If anyone is on here looking for the source of odd vibrations then this sounds like an easy place to start:

1) are propshafts slightly out of phase?
2) is the nub in the missing tooth or have they reassembled in the wrong place?

Reminds me, I haven't greased mine in ages.

MrGorsky said:

Where were you 10 years ago!!

Click to expand...

I was still in school