New here, just inherited a 1998 Bravada Smartrak 253,000 miles.

Swapped the inlaws for Grandma's Buick. (Buick has AC which works better for them in Arizona and the AC in the Bravada is shot which is fine for us here in Utah but I figured the Smartrak AWD would be nice for the snow).

Here are the issues I've run into:

#1) No overdrive. Zero zip nada. Trans shifts firm and doesn't slip through any of the gears it just has no overdrive...

I'm a Jeep guy so I'm not too familiar with this rigs.
I wondered if it's just a sensor or TCU?: I assume the trans is a 4L60E right?


#2 Smartrak does not work I did some research and it sounds like this beast has the NP-136 single speed transfer case. Should step one be changing the fluid? Then encoder motor then clutch?
Is this a pretty common failure on these or can I hit the junkyard for parts?

#3 Also where can I look up the RPO codes? Link on this website? I'd just like to know the diff gears and the rest of the build sheet.

Thanks much,

 

my .02

1) The no overdrive condition could be caused by a faulty tps. I'd start by researching how to test a tps!

2) Im not too familiar with the smart-trak system, hopefully someone can chime in with more info on that.

3) Heres a link to a thread that has info on the rpo codes. If you scroll down, you'll see a post from swartlkk with a link to an incredibly long list of every rpo code! I've used that list a few times myself (thanks swart!)
https://blazerforum.com/forum/2nd-ge...po-codes-1989/

 

Is the SES light on?
Did you retrieve DTC's?
What order were they retrieved in?
Yes, it's a 4L60E transmission controlled completely by the PCM.
Torque converter not locking up should set a DTC in memory. Possibly indicating a problem with the TCC, (Torque Converter Clutch) solenoid. A faulty TPS, (Throttle Position Sensor) can cause transmission shifting issues but would most likely cause engine driveabilty issues as well, hesitation, stalling etc, and most certainly set a DTC in memory.

The NV136 uses a special fluid, AutotrackII, that needs to be changed regularly. Dealer has it for sure, and possibly auto parts stores.