Conventional vs Synthetic Dexron III

[RobZ71LM7]

Many people on the F-body and GM truck boards I frequent do not recommend synthetic Dexron III because they claim it will cause the transmission to slip. Some have said they've experienced slipping after a switch to Mobil 1 ATF in 4L60-E or 700R4 which went away when they switched back. Does anyone have any specifics about the Dexron III standard so we could see how much deviation there can be between fluids meeting this standard?

[ October 01, 2003, 05:29 PM: Message edited by: BOBISTHEOILGUY ]

 

[Pablo]

I disagree. Synthetic ATF will not cause the tranny to slip. Maybe sounds true, but it's not reality.

 

[sbc350gearhead]

I just put Schaeffer's 204s synthetic blend ATF, in my 98 GMC, and I can't tell a difference in shift quality. I was worried about the same thing, which is why I decided on the blend. Maybe next time I will go with mobil 1 ATF. The Schaeffers did wonders for my camry though.......it now shifts like new.

 

[MolaKule]

I have used both Amsoil and Mobil (in 700R-4), and Schaeffer's 204S (now running it in a 4L60-E) and have not experienced any problems with shift.

Don't know where these guys come up with this stuff!

 

[Ken2]

Probably had a worn out transmission in the first place, and tried syn ATF as a cure all.


Ken

 

[cousincletus]

Have used Amsoil Universal ATF in a Jeep Cherokee for over four years with no problems. Also use the Cherokee for towing and get good shifts under hard usage.

 

[Greaser]

Been using Mobil 1 Synthetic ATF Dexron IIE/Mercon in my 99 Jeep Cherokee with the AW-4 tranny for a couple of years now...works great!

 

[Alex D]

I am using Mobil 1 ATF in my 4L60E in my 1996 Corvette. The shifts right after the complete fluid and filter change became a lot smoother in part throttle mode. WOT upshifts are still the same firmness.
I will go back to genuine GM Dexron III next year since my tranny never gets hotter than 190F anyway and I don't drive the car that much.

 

[RobZ71LM7]

Hmmm, this leads me to believe that maybe they're confusing smooth shifts with slipping. thankls for the input.

 

[pgtr]

While I have no personal experience, here's a thought that's been around for a while. In old TH400s and TH350s, some folks prefer to go w/ Type-F rather than Dexron. Why? Because GM apparently always liked to go for 'smooth' shifts and Dexron was an important part of that equation apparently. By switching to Type-F much 'crisper' Ford-like shifts could be had that many people w/ TH400s or TH350s found preferrable. Don't know if this has any applicability here nor advice it per-se - just an old 'trick' that has been around a while.