smart trac help

[420420]

my 94 bravada acts like its in 4 whell all the time cvc joints bind when i turne verry sharpe it acts like my k5 in 4x4 on pavement

[Chris Stewart]

Your positraction unit in the rearend might be binding a little...I'd try going in circles in the grass or dirt to try to loosen it up little by little. Gradually tighten the circles...don't start off full "lock to lock" in case the front CV joints are stiff or worn out. That's the way had to do my '70 GMC and '92 Dodge. The front wheel ujoints used to stiffen up. Have you checked the front CV boots?

[420420]

ok its back together with the same vibrations as before and 2 trouble codes 12 & 15 it runs the same as before same vibration while excelerateing and less power than before so $450 latter and no gain some loss any other ideas

[Chris Stewart]

Your code 15 is a Coolant Temperature Sensor Circuit, low temperature indicated. Check the connector and wiring to your coolant temperature sensor...unless your coolant had a reason to go to -27F for 30 seconds where your at.

Regarding your wheel binding problem, does it do it in reverse?

[420420]

ok i fixed the code 15 forgot to plug in a sencer on the lower intake oops anyway it still binds in revers but not as bad i took it for its first drive today 108 miles rounde trip runs great but still vibrates really bad while excelerating ounce you are at youre speed its fairly smooth if you put it to the floore its smooth if you try normal it will vibrate um the clunk showed its self today really bad to were i had to unhook the all wheel drive to get home the driver cvc broke but the front will still act like it has a locker after i replace it so i aint doing it till i figure out the front diff the cat is rattleing annoying as he** at stopp lights we timed it with a timing light today and it wase off a little we set it and whate a difference runs great but i am ready to sale it if it doesent straighten up the rear end needs new barrings to so i might as well put my rear disk rear end under it while i am there o yeah i serviced the tranny transfer case and difs yesterday this is the most pain in the a** s10 i have ever had its always something o well i got it cheep so i will probley fix it up it drives nice besides the vibration

[420420]

will a s10 blazer cvc fit it

[Chris Stewart]

I don't know.

[420420]

i have a code 32 howe do i fix this one

[Chris Stewart]

You have an EGR problem and this is how Jim from Phoenix solved his EGR valve problem for a coupla bucks...I'll do mine the same way when my drilled disk fails. After you pull the EGR valve, work the plug valve, push it in and out a few times with your finger to be sure it's not binding. If it won't free up then keep working it till it does. Like Mike says, this may indicate fueler problems to come.

Says Jim:
"With the intake cover off, this is a good time to pull the EGR valve, clean it, and put the fine mesh screen over the exhaust port feeding the EGR (The EGR has 2 ports, one has the plug valve and the other is the port from the exhaust feeding the EGR,CS). I use the stainless steel fine mesh screen from a sink faucet aerator and a drop of glue to hold it in place. When I did the hoses, I inspected my EGR, which has worked perfect for 10 months and about 14,000 miles. There was a small pile of carbon laying at the bottom of the screen, proving the need for same."

[420420]

its all fixed and its for sale 2,500 obo

[Chris Stewart]

After all that work, you're gonna sell it?

[420420]

yeah my girlfriend wants a car

[chcknugget]

Does it still bind up? I've heard there's a magical "blue?" transfer case additive that makes turning into parking spaces smooth again.

[lou S.]

The "magical" additive is most likely an anti-chatter additive that can only be gotten from the dealer.

[chcknugget]

It's actually not an additive like I thought, it's the actual fluid that goes goes into the case. It's a "blue colored fluid" called AUTO-TRAK II.

I found this in a the astrovan forum and thought it might be of some interest, however your car is a different year and I'm pretty sure its case uses different fluid anyways (check and see if you have the same transfer case p/n).

Bulletin No.: 99-04-21-005B

Date: September, 2002

TECHNICAL

Subject:
Transfer Case Shudder
(Flush and Replace Transfer Case Fluid)

Models:
1999-2003 Chevrolet Astro (AWD)
1999-2003 GMC Safari (AWD)
1999-2001 Oldsmobile Bravada
with All-Wheel Drive (NV136) Transfer Case (RPO NP4)

This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 99-04-21-005A (Section 04 - Driveline Axle).

Condition

Some customers may comment about a vibration (shudder) during tight turning maneuvers on dry pavement at vehicle speeds less than 8 km/h (5 mph).

Cause

This condition may be caused by a slip-stick of the clutch plates in the transfer case clutch pack. On 1999 and newer models, the preload that is designed into the clutch pack may contribute to the condition. In addition, contamination of the fluid may interfere with the friction modifiers.

Correction

Flush and replace the transfer case fluid on affected vehicles using the following procedure and the part number listed below.

Perform the following diagnosis prior to flushing and replacing the transfer case fluid in order to properly identify the shudder.

Diagnosis

1. Verify the shudder in the vehicle. The vehicle needs to be at operating temperature (driven at least 5 miles) for proper diagnosis. After the vehicle is at operating temperature, drive in a tight circle just short of steering wheel lock, at a speed less than 8 km/h (5 mph) in order to identify the shudder.

2. Identify what rear axle type the vehicle has.

^ If the vehicle has a standard rear axle, then proceed to step 3.

^ If the vehicle has a locking rear axle, remove the front propeller shaft. Refer to the Propeller Shaft subsection in the Service Manual. Drive the vehicle as outlined in step 1.

^ If the shudder goes away, install the front propeller shaft and proceed to step 3. Refer to the Propeller Shaft subsection in the Service Manual.

^ If the shudder does not go away, the locking rear axle may be the cause. Review the owner's records and determine if the rear axle was serviced at the first scheduled oil change. If records indicate that the axle service was done, then revaluate the condition using diagnostic information in the appropriate Service Manual. If the rear axle was not serviced, service the rear axle.
INFORM THE CUSTOMER THAT THE AXLE SERVICE IS AN OWNER'S MAINTENANCE ITEM NOT COVERED UNDER THE VEHICLE'S WARRANTY.

^ Install the front propeller shaft. Refer to the Propeller Shaft subsection in the Service Manual.


3. Flush the transfer case with the blue colored fluid (AUTO-TRAK II) using the procedure and part number listed below. Perform the flush procedure even if the transfer case contains the blue colored AUTO-TRAK II fluid in order to remove any possible contaminants. The AUTO-TRAK II fluid contains an improved friction modifier that should correct the slip-stick condition. Refer to the Transfer Case subsection in the Service Manual for information on draining and filling the transfer case.


Flush Procedure

Important :Refer to Corporate Bulletin Number 99-04-21-001, dated April 1999, for important information on removing the transfer case drain and fill plugs.

1. Drain the transfer case fluid.

2. Refill the transfer case with 2 L (2 qts) of new fluid, P/N 12378508 (Canadian P/N 10953626).

3. After refilling the transfer case, drive the vehicle a minimum of 8 km (5 mi).

4. With the transfer case at operating temperature, drain the transfer case fluid again.

5. Refill the transfer case with new fluid.

Important :The vehicle may require approximately 160 km (100 miles) of driving before the condition is completely corrected.