For firmest shifts in GM LS1 4l60e?

[gregmp]

Is is correct to say that a Dexron III/Mercon spec would be better fluid to use than a Multi-Vehicle ATF with Mercon V approval.
Wouldn't the friction modifiers in Mercon V and Multi Vehicle Synthetics allow the trans clutches to slip more thus generating more heat, breaking down the fluid faster?

I want firm, consistant smooth shifts.

 

[SargeGTO]

Fluid may play a smaller role but programming the shift points and firmness are what you are really after. You can have a tuner do it or I use HP Tuners to program my cars....

 

[JohnBrowning]

If you want firm you want Trickshift or the like. Redline D4 will firm up the shifts as well.

 

[gregmp]

I like the way the transmission shifts on the Dex III fluid. I don't want to stiffen it. This transmission is a self adjusting one that adapts to driver input and does a good job at it. I don't think I need a retune for it.

The point is that with multi ATF's, Dex VI, and Muti Sythenitics taking over the aftermarket fluid industy, doesn't friction modified ATF shift softer and slower, which is bad for transmissions and bad for the firm type of shift I like.
I just want it to continue to shift like new with whatever fluid I put in on my next cooling line pump out and fill.

 

[unDummy]

If your transmission adjusts for the fluid, the shift time is controlled. So, softer/slower isn't always going to happen with the more HFM'd fluids. Sometimes it could also happen with the lesser HFM'd fluids.

Use the best ATF that you can afford that meets the requirements of your transmission.
Since it is a 4l60 GM product, dexronVI is an easy choice. Full synthetic Dex/Merc(Rp/M1/RL/Ams...) are also good choices.

 

[JohnBrowning]

First that transmission might use fuzzy logic to tune shift points tot he driver but it makes no alloances for wear from the clutch pack's and steel's. It ability to adjust for fluid differences is also limited to nill wich is why you can kinda adjust the shift fill by useing fluid's with differt coeefienct's of friction. Firm shift= long life, fast on the drag strip and spilt coffee. Soft shift's= slipage wich means shorter transmission life, shorter fluid life, slower acceleration etc....... If you like the way it shift's with Dex III just use a high quality DexIII fluid like Valvoline Maxlife it has a proven track record of good service life and good shift quality! You can not go wrong and most times AAP has it on sale in the gallon size.