Dexron VI ATF -

[JK McDonald]

What ATF is everyone using in their automatic transmission ? Has anyone tried the latest GM spec DEXRON VI synthetic fluid during a filter service ? I've talked to a couple of other owners who have used Mobil 1 Synthetic ATF but they noticed after only a short time the torque converter seal began to leak worse. Are the synthetic brands supposed to be thinner than other automatic transmission fluids ?

The 928 blogs are all over the map discussing transmission service issues. Anyway I'm leaning toward DEXRON VI this time around unless someone has had a report of their transmission suddenly coughing up a clutch pack after using it.

Michael

[Mrmerlin]

I suggest to use Valvoline Max life ATF dextron VI it works in the trans and the PS systems

[JK McDonald]

Hey MrMerlin - Do you have any idea what the track record has been using one of the synthetic ATF formulas in our transmissions? Most of the ones I've read about specify that they are a "very low viscosity". I realize that the modern synthetic ATF's are loaded with all the best fortified anti-friction goodies and packed with vitamins, but wouldn't a thinner synthetic get past gaskets, seals and pistons easier in a transmission with worn internals.

Does any one know what the viscosity is rated to be for the synthetics vs the other ATF fluids ? I'm on a learning curve while trying to find the best set up for my 4 speed automatic transmission. There is beginning to be a small delay (slight mushy spot ?) when she shifts from 2 - 3 unless pushed a bit during acceleration. It's a little more noticeable under very light throttle.

Is there an external band adjustment available from the outside of the case. I've tweaked the vacuum modulator adjustment a bit (good solid vacuum signal) and checked the bowden cable setting with no improvement. Miss Purdy's drive train is holding up well so far, I'd just like to maintain my 30 year old transmission within a reasonable life expectancy. Currently the odometer is showing 135k miles with no major tear downs.

Michael

[Mrmerlin]

this fluid is also backwards compatible to Dex 3, 4 , 5, 6,
I have used many gallons of it and no issues, it works.
You might neeed a fluid change and to install a few springs from this shift kit from Superior shift kit for the 722.3 gas Amazon has it,
also pick up a bottle of Lubeguard additive for dextron 1 oz for each qt

[stepson]

I've used Dexron VI in a couple of my cars. It seems to work fine with no problems.

[JK McDonald]

Thanks for the information. I'm in the middle of a routine filter replacement and ATF change. I've read about the mixed results when trying to flush an older transmission so I just drop the pan when the oil is still warm and drain the torque converter. After about 8 years sorting I really can't complain about any serious issues after bringing Miss Purdy back to life from a previous very negligent owner.

I try to keep my maintenance reasonably close to the recommended intervals and typically update my DNK (Did Not Know) folder with lots of the information from this site.

Thanks again, Michael

[JK McDonald]

Just to pass on a few observations - I finished changing out the transmission filter and ATF. Put in Dexron VI as many had recommended and it has made a very noticeable improvement in how Miss Purdy shifts through the gears.

The slight delay (mushy spot) I'd begun to notice between 2 -3 has virtually disappeared. Hopefully this magic mystery fluid is a long term solution and I wont now be tempted to get too aggressive with my new car.

Michael

[stepson]

Michael,

It could have been the filter replacement that did the trick as much as the new fluid.

[JK McDonald]

Hey Stepson - I'd already told my wife that it was the mechanic

Michael