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Changing Transfer Case Fluid

38K views 9 replies 3 participants last post by  kennysmoke 
#1 ·
Ok... So through some research on here I have determined that the slight binding sensation I am experiencing on my 2000 AWD is related to my transfer case fluid. So, I'm going to do the right thing and change that out. Questions:

I know that "Auto Trak II Transfer Case Fluid (GM Part No. 12378508)" is highly recommended, and I plan on using this. How much will I need? Should 2 quarts be enough?

Since the above mentioned fluid is expensive, I want to get the most out of it. Would I benefit from and not cause any damage by using some clean DEXRON-III in my transfer case for a week or so? I would then drain this and fill with the Auto Trak fluid.

I've also read that you should replace the drain plugs when you perform this work. Is this really necessary? Fill/Drain plug info "Replacement Drain Plugs (Part No. 15032997)".

Thanks!

A how-to I have been referencing... http://www.gm-trucks.com/resources/how- ... ase-fluid/
 
#2 ·
Just picked up the Auto Trak II fluid at a dealership. It was $8.95 which doesn't seem terrible (I read somewhere else that someone paid $11.99).

Will probably pick up a fluid pump on my way home from work and crawl under the van to get this done tonight. Any feedback on the "flush" would be appreciated.

Thanks!
 
#3 ·
No, do not put Dexron in the transfer case. Ever. If it needs to be flushed, you need to put AutoTrak II in, run it 100 miles or more, then drain and refill with more AutoTrak II.

This is exactly what the TSB from GM says to do if the customer experiences binding or hopping in tight turns.

I've not replaced the fill or drain plugs. I use white goop on the threads (technical HVAC term used by my bf for sealant put on with a little paint brush) in place of the black goop GM used.
 
#4 ·
Leann thanks for the reply! Point taken, I will inspect the fluid when it is drained. If it is clean I will not do a flush in 100 miles, if its not a flush will be in order. When I stop to get a pump I'll ask if they have some white goop.
 
#6 ·
Thanks again for the reply. I do have Teflon tape, will probably just use that.
 
#8 ·
Found the Technical Service Bulletin, originally posted by 'astro355':

Transfer Case Shudder (Flush and Replace Transfer Case Fluid) #99-04-21-005B - (Sep 10, 2002)
Transfer Case Shudder (Flush and Replace Transfer Case Fluid)

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.
o 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.
o 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.
o 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.
6. If this procedure does not correct the shudder condition, please call the Technical Assistance Center for further instructions.

Parts Information

Part Number

Description

Qty

12378508 (Canadian P/N 10953626)

AUTO-TRAK II Transfer Case Fluid

4 (1 L) containers

Parts are currently available from GMSPO.
 
#9 ·
Better late than never...

Transfer case, drivers side:


My tag - Syracuse, NY:


Drained. Bolts were 18mm I think, easy to get out, remove the fill plug first to make sure its not stuck. I think the last person to change my fluid did it on uneven ground, when I took the fill plug out fluid poured out of the fill hole, my drain pan wasnt under the van and I got fluid everywhere. Make sure you have your drain pan handy and hold it up near the hole when you undo the last few threads. When you undo the drain plug, fluid will shoot out at least a foot, make sure you are holding the pan up and put it to the ground when you can watch the flow:


The juice:


The crapiest pump in the world. You need a pump to complete this job and this one died about halfway through the second liter. I had to ghetto rig it and limp through the last half liter (this alone took 45 minutes!!!). I ended up changing/flushing again about a week later and bought a nicer pump, it was much easier and faster:


This is why people buy new plugs, or put teflon on the threads. I used teflon tape, the first time I put too much on and it bunched up. Put a very thin layer on the second time and think it stayed in place on the plugs:


Metal flakes (I think, the pan was under the car the whole time and debris may have fallen off my filthy car)!!!! Not good, I guess this is why it needed changed. I flushed the fluid out after a week of driving and didnt have any flakes this time around:
 
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