Could the wrong diff oil cause thw diff to tighten up too much?

Submitted: Tuesday, Feb 03, 2009 at 21:05
ThreadID: 65675 Views:10591 Replies:6 FollowUps:1
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Bought a 1991 GQ Patrol about 6 months ago. Took it straight to my local mechanic who changed ALL the oils from front to back.
My rear diff seems VERY tight! Sometimes when I back out my driveway or a parking space, it feels like the diff almost locks and I have to drive/force the vehicle through the resistance. Not every time. Then this afternoon I did a quite sharp turn on bitumen and the rear tyres screeched.
My question is, could changing to a different brand of diff oil have caused these problems? and/or could changing to another brand of diff oil help solve the situtation?
Thanks in advance.
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Reply By: Bryan (WA) - Tuesday, Feb 03, 2009 at 21:16

Tuesday, Feb 03, 2009 at 21:16
Hi mackayboy,
If the local mechanic has put rear diff oil in it and it is to thick it will certianly make the LSD very tight..
I have a 92GQ and I use Penzzoiil LS90 - have for years and Im very happy with that weight of oil. I know on the patrol4x4 web site a lot of people talk of using a heavier grade oil - I think its 110 they use to make the LSD tighter.
it would be worth while checking what he put in, or even just change it yourself to the oil you want - very easy to do. I always do all my own oil changes so I put in exactly what oils I want.

Im also using fully synthetic oil in my gear box and have found that to be a huge improvement.
hope this helps.


regards
Bryan
AnswerID: 347439

Reply By: Foxhound (WA) - Tuesday, Feb 03, 2009 at 21:21

Tuesday, Feb 03, 2009 at 21:21
I have been out of the trade for a while but I am sure the GQ has a limited slip diff. If the wrong oil was used it may cause this problem. Limited slip diffs use clutches to limit the slip when turning corners and for more traction so need the correct type of oil. You should get the oil changed straight away and the problem checked out before any more damage is done.
AnswerID: 347443

Reply By: mechpete - Tuesday, Feb 03, 2009 at 22:32

Tuesday, Feb 03, 2009 at 22:32
tell me is it an automatic transmission , I ,m on my 2nd GQ 1st was an 89 build my current one is 97 , the old one ,I had the trans rebuilt , seemed ok for a whlie then it did started again . the 97 ,does it only once in a while ,not as noticeable , only does it the first time you move it for the day and for a few seconds in reverse only
cheers mechpete
AnswerID: 347456

Reply By: mechpete - Tuesday, Feb 03, 2009 at 22:36

Tuesday, Feb 03, 2009 at 22:36
just another comment .
had the 89 for 6yrs and the 97 has been my toy for 12 yrs doesn,t
get any worse .
mechpete
AnswerID: 347457

Reply By: ExplorOz Team - Kerry W (QLD) - Wednesday, Feb 04, 2009 at 01:26

Wednesday, Feb 04, 2009 at 01:26
Hi Mackayboy.

You will find that Penrites Limslip 140 will fix the problem. (It takes 2.2 lit or a bit more if you can fit it in)
The Patrol LSDs are best off with the heavier oil.
It will be incorrect oil, additives or water recently added to the cocktail causing your problems.
If its water check your breather hose.
If this does not work there could be a problem with the diff or drivetrain.

Patrol LSDs are fairly tight anyway but not that tight.

Do a forum search for "Limslip 140" there is plenty of info on this solution. (Use inverted commas to narrow down results - should be 31 threads on this oil)

hope this helps

Kerry W
Kerry W (Qld)
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AnswerID: 347470

Reply By: hl - Wednesday, Feb 04, 2009 at 11:41

Wednesday, Feb 04, 2009 at 11:41
This sounds like your diff is just working properly!
After all, it IS a limited slip diff and that is what they are supposed to do. On a patrol with a good diff, you cannot turn the wheel by hand if you jack it up on 1 side and release the handbrake (out of gear too). That is how tight they are when they are new.
AnswerID: 347495

Follow Up By: hl - Wednesday, Feb 04, 2009 at 11:43

Wednesday, Feb 04, 2009 at 11:43
As for the tightness when backing up etc, you don't have it in 4WD and the front hubs locked by any chance?
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FollowupID: 615686

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