Olds called it "Smartrack", I think "Dumba**track" is more like it. It quit a long time ago, but was working intermittently. Even the night I last tried it, after the tow truck got me out of the holes I had dug, (first the rears, 2WD only, then after ign. off/on, it worked enough to dig the fronts in too!), it just happily drove out of the deep sand in 4WD.

So, is there such a thing as a diagram of the whole system? One with all the sensors, actuators and logic; electronic, vacuum, cable, hydraulic, maybe even that special receiver tuned in to the Galactic Force, -I found it bolted to the plasmic discombobulator.

I have done all the 4WD searches I can think of, (even vacuum actuators) and cannot find such a thing for my Bravada, which may not even have a 4L, probably just 2H AND 4H.

Going back to searching now, I'll delete this if I find that drawing, until I run up against the 'wall' again.

Bruce Hinton

 

What year are you driving again?? Best to just add your vehicle information under your "Live it On the Edge" signature text...

If it is a pre-98 Bravada, then you have fulltime AWD with a dedicated 30/70 F/R split. If you have a 98+, then you have the NP136 transfer case which is automatic AWD. It can transfer 100% of the power to the rear and up to a 50/50 F/R split when necessary. The front axle for both arrangements are connected all of the time so there is no vacuum actuator or transfer case switch. Neither of them have a low range.

 

Stupid of me to forget the basic car description, -just focused too much on the task and unaware of how different some of the 2nd gen vehicles are from others. My Mopar experience is of no value here.

If there is no vacuum actuator, then as for the 4WD engagement-decision process, is it all internal in the transaxle? If I could put a crow bar through the floorboard and stir this thing to 4WD with mechanical authority, I would do it in an instant. Fancy electronics are nice, but where is the fail-safe? If I had been nearer the ocean at low tide, it would have been final curtain time...

I was part way through the DIY section, but although interesting reading, I had not found this subject yet.

Apologies,
Bruce

 

You will not find this subject as the NP136 is no where near common around here.

There is no real way to mechanically actuate the NP136 transfer case. You could swap it out for an NP231 and cut a hole in the floor, but then you really would want to get your PCM tuned to remove the programming for the NP136 transfer case. And then you would need to get a front axle out of a 4wd Blazer and all of the associated parts (vacuum actuator, cable, maybe vacuum lines, etc).

 

As Charlie Brown might say on my behalf, AAARrrrrrgggggghhhhhhhhh!

I guess I have no alternative; I'll try to get a manual that covers it, or get a small independent shop to do a limited analysis with a cost cap.

Now you know why I drove it sans 4WD for nearly two years.

You're golden, as in gold plated, Kyle, thanks for looking in on my travails.

Bruce

 

The first thing I would do before taking it to someone is to service the transfer case. The NP136 requires GM Autotrak 2 fluid. If the fluid that comes out is quite dark (should be blue), then refill with new and drive it for a week or so and then drain/fill it again. You may need 4 quarts of fluid. When I serviced the transfer case on my old 2000 Bravada, I bought 2 quarts and still have some of the 2nd quart to use in the transfer case on my Rainier.

 

I really learned a lot and have some good people here to thank, but this saga has come to an end. Recently, the transmission blew up a second time, (same deal-had 1 & 3 lost R, 2 & O.D.)

I don't hit the tranny hard or drive it hard, except for a couple of times, it would Not go into gear even waiting extra time, then when gas was applied in traffic you have to clear the intersections, a pretty good lick would come of those.

I let it go to a mechanic for $700.00. His niece needed a car, and he could fix this one himself.

Wish you guys well, I sure miss the best of the days when it was a 4WD, and reliable.

Bruce

 

I am not questioning your knowledge on this system or setup because you are by far one of the experts on this forum. BUT Just looking around I see that some companies sell Differentianl Vacuum Actuators for the 98-01 Bravada.

http://cgi.ebay.com/ebaymotors/01-20...item35ac84e46a

I just ask because I am trying to troubleshoot the problem with my mechanic and I don't want to replace the front differential and Transfer case if I don't need to. I know the front differential is shot because its whining like Brett Favre for attention. I changed the fluid in both the transfer case and front diff twice.

So if my transfer case clutch is locked up it would not make sense to only fix the front diff because the problem will most likely come back.

Is it possible that that ebay store as that product listed wrong?

 

Sure you are...

BINGO!!!

Why not try finding that part for your application at a reputable parts supplier (RockAuto, Autozone, etc) and see what turns up. Better yet, maybe take a look at your truck... It will be readily apparent that you have no such device... If, by chance, you do have it, then someone has done some major swapping with a regular 4wd s-series vehicle.

 

2000 Oldsmobile Bravada. I just have a problem with not knowing when the Smartrack is working/engaged/ or doing its thang. They should have put some sort of indicator to let the driver know when its working and when it isnt. So far, I have been in some extremely slippery places and haven't been stuck. Is there anything that I could install that would allow me to "see" when its working?