I have a 2000 Bravada that has the "hopping" problem during slow speed
turns such as parking lots, etc. The transfer case fluid has been
changed twice in 2.5 years, the last time being a year ago using the
recommended GM fluid. The hopping has gotten worse and a GM dealer
told me since I have a locking differential that I should probably
change the rear differential oil as well. The owners manual says to
only use GM axle lubricant, PN.1052271. There is no description of
what that lubricant is. They also give the same part number for the
front axle lubricant which is a standard differential and call it
"SAE 80W90 ". When I called the dealer they tell me that my book is
wrong and that I need this special SAE 75W90 oil at about 29.00 a
quart. Now if someone could please answer six questions for me /i
would be extremely grateful:
1. What is the correct oil for this axle?
2. How much do I need for a complete drain and refill?
3. Is there a drain plug on these axles or is there a plate on the
rear of the carrier that has to come off?
4. How likely is it that a rear differential oil change may cure my
5. If this is my problem what is actually happening in the
differential to cause this?
6. How much damage typically occurs from driving a car with this type
of symptom for any length of time and what will we notice?
Thanks very much for any advice. Lenny Stein.
some 'hop' on solid surface is considered normal with no repairs needed
or possible. i dont find it pleasant but i do find it on all models with
locking diff's (GM being the most bothersome).............you may end up
throwing money at it till sold w/no results......i know i really didnt
answer any of your ??? but if the owners manual aint right, how would you
possibly trust any stranger here for better info?........kjun
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Great Speed, Great Retention
What 4x4 do you have, 1 speed or 2 speed. What position are you running the
4x4 in. Rear diff is a locker type, if you're not spinning, should be no
limited slip action. Oil is 75w90, no friction modifier. In the auto
position, there should be little to no binding. I suspect an internal
problem in your transfer case.
Tell them to look up this bulletin
Shudder, Rocking Motion, Binding, Feels Like Vehicle is Stuck in 4WD (Crow
Hop) When Turning at Low Speeds (Replace Transfer Case Encoder Sensor and
Reprogram TCCM) #02-04-21-008A - (02/13/2003
This is what you need done to fix your problem. Of course, perhaps
this bulletin has already been performed...so you need to check on
that first. Even if it has, the encoder sensors are troublesome anyway.
It may need another one, and I've even seen some that need the whole
encoder motor replaced.
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