mgmshar

Questions: I have a 1997 Olds Bravada with Smartrak AWD...

1. I am trying to diagnose a problem. Can I remove the front driveshaft (goes from transfer case to front diff) and drive the vehicle without destroying anything? I am worried about damaging the viscous coupling in the transfer case.

2. What is the GM designation for the transfer case? (NP136 NP231, etc.)?

Problem: Under hard acceleration, particularly in lower gears, I get an occasional loud clunk. The event is severe enough that the whole vehicle bucks a little bit. It feels like something in the drivetrain is getting bound-up tightly and then suddenly releasing. During a hard acceleration through first and second gear, the clunk/bucking might happen 4 to 7 times. I have already changed the ATF fluid in the transfer case. The fluid that came out didn't look too bad - just slight discoloration - not burnt. If anyone has had a similar problem, I'm all ears.

Thanks,
Mike

MT-2500

If a true AWD you can not remove front drive shaft.
We need to know what transfer case you have for sure.
What no is on the tag on back of transfer case?
Do you have shift buttons on dash and if so what do they say?
What kind of fluid came out of it and what kind of fluid did you put back in it?
Have you checked for codes? Any check engine or transfer lights on?

__________________
Remember proper testing gives us the answer to many problems.
MT

muddog321

MT asked the right ones - GM has a big problem they found on the AWDs with the clutch packs in the transfer case so they switched to a new blue syn fluid dealer only 2 qts at $7 each and says to change (get that red Dexron out) and run 100 miles, change again (2 more qts) and hope that fixes the clutch pack binding or next is a rebuild. All the newer autotac 4 button np236 cases require that too as they also have the same clutches.

Chris Stewart

The '97 Bravada has the viscous clutch transfer case and not likely to be the source of your clunk.
With the hood open, motor running, transmission in drive & foot on the brake, mash the gas pedal a little bit & not letting the car move, look through the opening between the hood and cowl to see the motor. Does the motor raise up more than 1/4 inch and suddenly quit raising up?
You likely have a bad motor mount and it's hitting it's built in "retainer" causing a "hit" on your drivetrain and front chassis.
Give it a try and let us know what you find.