If a flush didn't remedy the problem, the clutch is gone. Another member just had the clutch pack replaced in his NV136 to the tune of ~$350, IIRC.

My old Bravada and current Rainier did/do not hop around corners. If you get on it in a tight corner in a parking lot/etc, it will bind up a bit but then release, but not while coasting.

I would not recommend the removal of the front driveshaft.

 

ohsofly- Thanks so much for mentioning that. Every time I watch a Sy/Ty truck on Youtube, or whever... I have wondered about that. Do you know if a 100% stock Sy/Ty with the Borg-Warner 4472 can run on a REGULAR Dyno, meant for a RWD vehicle, at all?
Then, there are the Dyno's made for FULL-TIME "4wd" (on dry pavement) with center differentials/viscous clutch set-ups...like the Old 3000GT VR4's, Elclipse GSX's, and the newer (awd) Lamborghini's have...where the front AND rear wheels drive the Dyno. Could a Sy/Ty truck run on THAT type of Dyno, you think ?

packofqtips- Yeah man... I'm not. I would only run different sized tires if I knew that the transfer case was FOR SURE able to be DISENGAGED... and was.
Thanks for the heads-up though man.
Do you know if UNBOLTING the front axle- so it's NOT in there anymore would hurt the transfer case..or if that would hurt the truck to do for a few years ONCE per year ?

swartlkk- Thank you for the response. Yeah, actually... maybe the SmartTrak is working as it should...b/c it doesn't bind at all (I don't think), when driving in a straight line- it's ONLY on tight corners and backing up, where it's sticking, but it DOES release for the most part after turning.
Why wouldn't you recommend the removal of the front axle/driveshaft?
(Well- I def do not want to remove the entire DRIVESHAFT...I wouldn't have to do that, would I? I thought maybe I could just remove the drive "Axle" itself... and put it back October....when I'm finished running the different size tires.


Do you know if pulling ONLY the "ATC" (auto transfer case) fuse, under the hood- will allow the front differentail to NEVER receive power, from the transfer-case? I pulled that fuse, and it FELT like it was still in AWD ! ???

I wish I had the NV236, still... I LOVE "2wd"... and my Bravada will NEVER be that! (since the front axle will always be engaged to the differential... unless, it is unbolted (but that seems like kind of a crazy thing to do...and may be too much work)

Should I just buy two more tires (in size 245/35/20) and have them mounted- then put all four 20" wheels (with the same size tires) and run them with the SmartTrak? I feel like the soft rubber on my brand new Kumbo "SPT" tires is going to get destroyed from all of the binding around tight corners and awkward road angles & hills, though.

One cool thing about both the Bravada's NV136 and the other trucks that have the NV236 is...DRIVING IN THE RAIN is def safer.... and also a lot of fun! haha

Hey bro- thanks again for your help & replies... ! AWESOME SITE.

I wanted to add that... I just found something else out- that may be my 'culprit' to the hopping/binding on my 2000 Bravada. (with 46k orig miles and a freshly flushed transfer case)

I pulled both the ATC, AND the 4wd fuses...just to be sure the truck was only driving the REAR wheels. And when turning, on a sharp bend, especially when moving SLOWLY... I noticed that the BACK axle is sticking!
The 'locking REAR differential' <--as GM calls it... seems to be BINDING.

Does that simply mean, I need to have the rear axle drained, flushed, and filled?


Thanks to all of you- who have responded- especially the ones who are familiar with the '98-'01 SmartTrak system... you've made me feel MUCH better & confident about my purchase of the SUPER CLEAN '00 Bravada that I found and picked up last year with only 39k miles on it. So...THANKS for the support fellas

 

It is possible that you have a problem with the rear locker. Pull the cover and see. Refer to my Rear Axle Service thread for further information.

I hope you have the same wheels on each axle... Like 245's on front and 255's on back...

 

Right... & thanks bro (yeah, I def wouldn't put different sized tires unless I knew, FOR SURE...that, it was safe to do so (i.e. If I find out there's a way to DISENGAGE the SmartTrak, by pulling the fuse, for example)

Here's my new question:
What happens exaclty, when the 20amp "ATC" (Auto Transfer Case) Fuse (the one under the hood) is pulled out? It SEEMS that doing that DISENGAGES the power to the Transfer Case.

So "IF" removing the fuse does disengage the Transfer Case...(which I'm still not 100% sure), making my Bravada run in "2wd" mode (with the front axle still be 'engaged' to the front differential but NOT receiving power & the transfer case), and the transfer case clutch isn't engaging at all, then would I be able to run 255's on the rear (drive) wheels with 245's up front, without any problems ?

Also- swartlkk...Thanks for the nice link man. That is definitely something I think my Oldsmobile could use. Even though the miles are still low, it IS a 10-year-old vehicle. I'm going to do that this weekend.

GM doesn't use SYNTHETIC gear oil, from the factory either, probably- do they?

***I'm sorry to be a pain in the butt...& kinda repetitious guys-
I'm about 99% sure that what I need to do, in order to install my set of 20" wheels/tires is:
have the two 255/35's that are currently on two, of the four, wheels pulled OFF- go and buy two NEW (matching) 245/35's...like I have on the other two 20's- and have them mounted/balanced. ha

BUT, before I go and spend over $300 for the two new tires + mounting/balancing...are you SURE that I would NOT be able to run the 255's in the back and the 245's on the front, with the ATC fuse being pulled out?

(also, I don't blame you for asking, swartlkkhaha, but NO- I am definitely not, and would never, run different sized tires per axle...ever. haha)

I actually haven't even attempted to put the aftermarket wheels on my Bravada yet.
It currently has an evenly worn set of (the exact same "UNIROYAL LAREDO" OEM) tires, in the orig factory size of 235/70/R15 on it.


I tested out the AWD when both the 20amp ATC fuse (under the hood) AND the 10amp '4wd' fuse (interior) were pulled and verified that the front wheels were NOT being driven, when slip was detected...

But I haven't checked to see if it's the same scenario, when only the ATC fuse under the hood is removed. I am doing that now!

How/why would it hurt the truck to run slightly smaller tires up front, when the Transfer Case fuse is removed..?? It seems that it should NOT hurt it.
If that's not the case though... and doing so could even POTENTIALLY damage anything- then I'd rather just buy two more matching 245/35's and call it a day.

I can't wait to hear your thoughts on this ATC fuse being removed... !
(you've helped me TREMENDOUSLY so far... thanks again fellas!)

BlazerForum rocks..!

 

DO NOT run different sized wheels, PERIOD. The clutch in the transfer case is preloaded and is always working regardless of whether the transfer case is stuck in 2wd or actually functioning as it is supposed to. With different wheels front and rear, the clutch is doing work regardless of whether the fuses are in.

Also, you need to check the wear on the tires you currently have on there. It depends on how long they have been on there.

Removing the front driveshaft may be a way around this, but I have also heard that the lack of resistance on the front output can cause issues with the clutch. That preload thing again.

It just isn't worth the potential problems which can be in excess of your $300 tire cost.

I do not believe that GM used synthetic gear lube as a factory fill in these trucks. That doesn't meant that you should use dino oil though.

 

Cool- sounds good. I am ordering two new tires today...and will run the same size (245/35/R20) on them all. Thanks for the explanation- That does make sense- b/c even though the front wheels are not being "DRIVEN" (when slip is detected, like normal), I can still feel them clutch packs working I think. Okay- gotcha though.

I'm interested to know (just curious- not that I even want to do it...too much hassle, for nothing beneficial), if removing that front drive shaft would allow the truck to operate just like the models with the NV236, in 2wd HIGH, though.

Last thing- I noticed my MPG did go up quite a bit with the ATC fuse pulled out... So, I was planning on leaving it out until winter approaches. Do you know if that will do any harm?

Def need to do that rear axle service, though.. with some nice synthetic gear oil. That should def help with the rear locker.


Thanks !

 

Okay, so with the ATC fuse pulled...the front tires are CLEARLY not engaged and have stopped binding as much, big time!

So, it turns out- there IS something going on with the Rear Locker on my truck. Will a flush and fill be the remedy for the 'sticking' of the rear tires around bends, ya think?

I will need to replace the gasket, right? (I'm assuming the gasket came with the new cover you bought..?)
Does anybody know what the GM part # would be for the new cover and/or gasket, by itself?

For under $20- you can't wrong with a nice NEW one!

Good stuff. Hopefully the drain/fill of the rear axle will help my problem.

 

You can examine it when you open it up. It won't hurt anything.

As far as the gasket goes, you should be able to get it pretty much anywhere. If you want, you can even use RTV to seal it back up without a gasket. Just let it set up for a few hours before filling the diff back up. I can't remember any of the part numbers...

 

So...it turns out that like 98% my problem is in the REAR axle! (the front just binds a TINY little bit. But, I actually put the ATC fuse back in and have been driving it without the "Service AWD" light)

THE PROBLEM IS--> The rear axle seems to be LOCKED all the time. When I turn the inside rear wheel is moving the same speed as the outside rear wheel. (faster than it should be- causing it to "skip" and "spin" on the pavement)
Do you think servicing the rear axle fluid alone with solve this? I hope so!

Also...LOL- after all the posts and questions about putting the 20" wheels on my Bravada. I ended up just throwing them on my girlfriend's '09 Escape- (also AWD)... with all brand new Kumho "SPT" 245/35's. Looks sharp. (although the 35-series aren't really for her car as much as my Bravada or my old '92 Typhoon-clone (my Tyclone) ha...

Here's a pic of her 2009 Escape Limited. (b/c it has all the chrome trim, the chrome wheels are MUCH more appropriate on her little 'suv' than my all white Bravada, you know?)

 

I'd say your next step is to open up the rear diff and have a look at what's going on. It definitely shouldn't be locked up. Something is wrong inside.