Chevy & GMC Vans

Got my 2000 AWD Safari earlier this year. It was early summer with no snow (Ohio). One summer rainy day I decided to see if I could spin the rear wheels. It started to, but then the front kicked in. I was happy knowing that when winter came, I was in good shape. 5000 miles and a good snow later, I have found the AWD does not work. Not even a little bit. On a snowy road, hit the gas and the rear end goes sideways (like my old GTO). Upon starting the van, the "service awd" light comes on for only 2 seconds or so. Per the owner's manual, this is normal. All fluids are full & in good shape. No noises, no shakes, no codes. 115,000 miles. During wheel slippage, I get no AWD, traction control light, or anything. Just like I'm driving a 2wd van. I wish I still had my '90 Safari AWD. Any ideas on where I should start? Is there any way I can test the transfer case or motor or ? I would also like to add that it is NOT in my budget to take this to a dealer. I can barely put gas in it at this point. Thanks to all for any help you can give.

Did you check the ATC fuse? Transfer case electrical connector?

Is there a way you can look at the front driveshaft while the rears are spinning? This will tell you if it's in the front end or t-case. Just be careful doing this. If the front drive shaft is not turning, you probably need to replace the shift servo motor. I am surprised the service AWD light isn't on if this is the case.

Let me know about the front end.

I'm not that familiar with this AWD setup. I was thinking that if either the servo motor or the fuse was bad, it should light my service awd light. I checked the fuse & it is good. It felt like the awd kicked in for a few minutes yesterday but that was all. I think I have either a worn clutch problem, or the servo motor is not engaging properly without setting a code. I was looking at this site...

http://www.astrosafari.com/viewtopic.ph ... se#p107456

...and think the clutches are my problem. When I changed the transfer case fluid last summer, it didn't look bad, but smelled bad (to me). The auto trac fluid smells bad when it's new however. What do you all think?

I don't know a ton about the AWD vans.. but, any chance it could be one of these?

http://www.dormanproducts.com/p-7841-60 ... id=7693460

I know we sell a bunch for the blazer/jimmys

risteff wrote:http://www.astrosafari.com/viewtopic.php?f=70&t=9856

Interesting pics of a disassembled NV136. The guy in that post tested the encoder motor by applying 12V directly to it. You could try that.

risteff wrote:think the clutches are my problem. When I changed the transfer case fluid last summer, it didn't look bad, but smelled bad (to me). The auto trac fluid smells bad when it's new however. What do you all think?

I think if it was your clutches, the fluid would be black. Drain off an ounce of it and inspect it. It would be full of suspended particles. You could dunk a magnet in it too.

Here's how I tested my AWD:
http://picasaweb.google.com/lh/photo/T2 ... j25GtBQIaQ

I'm pretty sure it's the clutches. I drained a little outta the x-fer case & it is alot darker than new fluid. Definatly smells burnt compared to new too. Currently looking for a replacement t-case locally (on a budget). If I can find one to rebuild I may go that route. That way I'm not out of a daily vehicle.

timelessbeing wrote:

risteff wrote:http://www.astrosafari.com/viewtopic.php?f=70&t=9856

Interesting pics of a disassembled NV136. The guy in that post tested the encoder motor by applying 12V directly to it. You could try that.

risteff wrote:think the clutches are my problem. When I changed the transfer case fluid last summer, it didn't look bad, but smelled bad (to me). The auto trac fluid smells bad when it's new however. What do you all think?

I think if it was your clutches, the fluid would be black. Drain off an ounce of it and inspect it. It would be full of suspended particles. You could dunk a magnet in it too.

Here's how I tested my AWD:
http://picasaweb.google.com/lh/photo/T2 ... j25GtBQIaQ

a little off path, but your passenger rear wasnt spinning, what was your final determination?

Interesting. I'll give that a try as soon as it gets above 20 degress here!

I just found a good transfer case from a 1999 Bravada. According to the seller, it is a "136" awd transfer case. I believe this is the same model as in my 2000 Safari AWD with a 4L60E. The local wrecking yards and GMC dealer are all telling me this WILL NOT interchange. A Safari or Astro AWD t-case will not interchange with any other model. Can anyone verify this info? This t-case is a few hours away and I'd had to take an all day trip for the wrong part. Thanks.

GnarliSafari wrote: little off path, but your passenger rear wasnt spinning, what was your final determination?

That's because the rear axle wasn't spinning fast enough to engage the limited slip diff, so it was behaving like an open diff. Likely, the passenger rear drum brake was touching so all the power was going to the more free-spinning wheel.

In subsequent videos, we applied more throttle, the G80 grabbed and both wheels spun:
http://picasaweb.google.com/lh/photo/pi ... 4e1usbPWEQ
http://picasaweb.google.com/lh/photo/0w ... 8cIQrkLm0A
http://picasaweb.google.com/lh/photo/YF ... TY85Icm2lg
(unfortunately you can't see much because it gets dark so early)

Everything was A-OK.

risteff wrote: A Safari or Astro AWD t-case will not interchange with any other model. Can anyone verify this info.

I thought an NV136 is an NV136 is an NV136. But maybe there's something I don't know. The transmission adapters may change from model to model, but it was my understanding the TC's are off-the-shelf.

The Bravada's didn't come with low range or 2WD options so I would say you would be safe in getting the Bravada unit. If it is possible, get the rear driveshaft slip yoke just in case they are different spline counts. Can you get pics of the case first to verify the front and rear yokes/slips are the same?

Found one today from an '01 astro. It's close to me and the same price (after fuel expense). I also found out from a local trans shop that the bravada 136 WILL interchange with an astro / safari as long as the servo motor is swapped. It seems the bravada harness is different than a Safari / Astro harness. I also was told that the bravadas used a 126, 136, or even a 146(?) transfer case from '99 to '01. They said this also goes for the denali, escalade, and trailblazer. Astro / safari is the only one that ONLY used the 136. I'm not 100% on this info, so use your own judgement. This is was I was told by a "local" (not chain) trans shop.

risteff wrote:Astro / safari is the only one that ONLY used the 136. I'm not 100% on this info, so use your own judgement. This is was I was told by a "local" (not chain) trans shop.

I think the shop is right, and that the 136 is matched up to the weight of the Astro/Safari. So that would mean Bravada's use something other than 136's.