Advice Please: Planning 4L80 Conversion

[Ranchtruck]

We do these conversions in the shop, we stock all the parts required to do the conversion, feel free to reach out.

 

[taskunitbruiser]

I thought that the 88861800 was supposedly repackaged DEX III fluid.
Looking at the label, it even says it contains automatic transmission fluid (along with other oils)

View attachment 880096


Then here is what I found on another site.

Originally Posted by GM #04-07-30-037D
MANUAL TRANSMISSIONS / TRANSFER CASES and POWER STEERING

Any vehicle that previously required DEXRON®-III for a manual transmission or transfer case should now use P/N 88861800. This fluid is labeled Manual Transmission and Transfer Case Fluid. Power Steering Systems should now use P/N 9985010 labeled Power Steering Fluid.

Consult the Owner's Manual or Service Information (SI) for fluid recommendations.

Some of our customers and/or General Motors dealerships/Saturn Retailers may have some concerns with DEXRON®-VI and DEXRON®-III Automatic Transmission Fluid (ATF) and transmission warranty claims. DEXRON®-VI is the only approved fluid for warranty repairs for General Motors transmissions/transaxles requiring DEXRON®-III and/or prior DEXRON® transmission fluids. Please remember that the clean oil reservoirs of the J 45096 - Flushing and Flow Tester machine should be purged of DEXRON®-III and filled with DEXRON®-VI for testing, flushing or filling General Motors transmissions/transaxles.

DEXRON®-VI can be used in any proportion in past model vehicles equipped with an automatic transmission/transaxle in place of DEXRON®-III (i.e. topping off the fluid in the event of a repair or fluid change). DEXRON®-VI is also compatible with any former version of DEXRON® for use in automatic transmissions/transaxles.



image near the top taken from https://www.amazon.com/Genuine-Fluid-88861800-Manual-Transmission/dp/B00BK7M1EK

The service bulletin portion was found at the below link, and the image below was found there as well

DextronIII vs Dextron VI - CorvetteForum - Chevrolet Corvette Forum Discussion

C5 Tech - DextronIII vs Dextron VI - I've had conflicting answers on whether or not Dextron VI is suitable for the 99 C5 standard transmission. Can anyone advise Thank you

www.corvetteforum.com

View attachment 880097

I think the larger point is that in the HMMWV application the automatic transmission fluid is pumped through the transfer case in the cooling loop. If one were to add different fluid than the recommended Dex III or VI to the TC it will mix with the fluid in the transmission and could lead to big problems.


Civilian applications just have the cooling lines for the transmission itself.

 

[Mogman]

I think the larger point is that in the HMMWV application the automatic transmission fluid is pumped through the transfer case in the cooling loop. If one were to add different fluid than the recommended Dex III or VI to the TC it will mix with the fluid in the transmission and could lead to big problems.


Civilian applications just have the cooling lines for the transmission itself.

The fluids do not mix unless the cooling loop in the transfer case fails

 

[taskunitbruiser]

The fluids do not mix unless the cooling loop in the transfer case fails

I topped up my TC fluid and the transmission dipstick showed a noticeable increase.

 

[Mogman]

I topped up my TC fluid and the transmission dipstick showed a noticeable increase.

Well then you have a problem, normally if the cooling loop in the TC is bad the TC will overfill with fluid and expand into the vent system, maybe it was just a coincidence.