anybody switch to synthetic auto trans fluid yet, if so what brand and any differences?

 

Use ONLY Dexron VI....The tranny ain't made for synthetic..

 

Dennis- All GM transmissions can use the Mobil 1 synthetic ATF. I used to have a problem with my Camaro auto overheating, foaming, and boiling out the dip stick after HARD driving. After using Mobil 1 this never happened again. I do not think Mobil 1 syn can be used in Jeep autos. It clearly states on the Mobil container which specs the fluid will meet. It is a great product well worth the extra money.
There is a new Mobil 1 IV syn ATF that I have been using in my auto Corvette and it keeps the temp down about 10-15 degrees according to the auto tranny temp. gauge. It is the same transmission we have in our auto H3's, think it is called a 4E60 or 4L60E- I may have forgotten the numbers but it is the same electronic controlled tranny. You can double check this by calling Mobil at; 1-800-ASK-MOBIL and speak to RON the tech there.
I also heard and again not sure , that our H3's come with synthetic AFT????
In any case, if I keep this H3 i will switch to the Mobil 1 syn. at 15,000 miles. As with the Corvette i will have all approx. 15 quarts replaced. I say I may not keep the H3 because I think I want to get a 2008 a little before my H3 goes off warranty. I do not want to have to pay for or have a repaired head/valve unit. Especially since I will most likely only have about 10k to 15k miles on it as it goes off warranty then at 20k and off warranty the head/valve problem shows up?

 

Draining transmission fluid from the pan doesn't get the fluid in the torque converter. Changing without draining the torque converter will cause problems...

 

Excellent point. But is there a way to flush it out?

 

Thanks Skeeet..I will stay with what I said..but I appreciate your candor and experience...However, I do agree with the fact that I will change my fluid at 15,000 to 20,000 miles too...Along with the Transfercase and differentials.

Joe..there is a method/contraption that can be placed on the tranny cooler lines (in series) and you run the engine and purge the tanny in the process adding new as the old dumps out

 

When i said I changed 15 quarts from my car I had Chevy put it on a machine that drains all the ATF from the converter , tranny cooler, lines and pan. You can also let your transmission pump do the work by detaching both lines and using the intake line to draw from a clean bucket the new fluid and the other line to empty into another bucket. Just be aware you need to fill/drain about 15 quarts and you can not let the pump run dry . Easier to take it to the dealer and I am sure most oil change places can now do this.

Dennis - If I am mistaken about how I should not use synthetic ATF please tell me where you got that info. Thanks

 

I'm not saying you're wrong..I'm just saying the wording is pretty absolute on page 5-21 of the owner's manual...In contrast to the requirement for the engine oil specs..Synthetic would fall into those specs and that's why I use Castrol Syntec...But the transmission fluid requirement says ONLY Dexron VI..Dealer also told me it would be a good idea to follow the GM recommendations with regrds to the Transmission.

 

Mobil says do not use Mobile 1 ATF in a H3. It is not now Dextron VI certified. I talked to the help line, and they said that in the future it will be certified , but not now. It would void the warranty they said.

I use it in a 2002 Tahoe, and the transmission shifts much smoother than with standard ATF.

 

I agree with Dennis on this. If your tranny ever failed, putting something else in other than what is recommended may void the warranty.