ATF viscosity/add pack effect on trans shifting

[04SE]

My 2010 CVPI had maintenance performed by a municipal garage. They serviced the transmission (4R75W) with Valvoline MaxLife the first time and Mercon V the second. 1st time was at roughly 50,000 with a filter change and 2nd time was around 80,000 with a filter change.

I have a programmer on my car (Diablo InTune) running a canned tune that includes transmission tuning/tweaks. Under normal driving the tuner would give nice, quick, snappy shifting. I was very happy with the normal/part throttle tuning. Under normal acceleration gear shifts were a nice subtle bump. However with the tuner WOT shifting was out of control. It was wicked harsh. I never use WOT so I never bothered contacting Diablo for a fix.

I recently put a U-Haul transmission pan on my CVPI that has an OEM drain plug, new Wix filter and fresh MaxLife ATF. I drove for 400 miles and thought I was noticing a difference in shifting but thought it was all in my head. Well, I just did my second drain/fill this weekend and again added MaxLife ATF. I now for sure am noticing a difference in shift quality. Under normal driving the shifts (with the tune installed) are barely noticeable. Maybe just a notch above OEM. Under WOT it is about as firm as the normal shifts had been prior to the ATF changes, just a nice firm bump, nothing wicked harsh like before. In talking with other people with this car/tuner combo their experience had been this type of shifting all along. They all thought I was nuts explaining the wicked harsh WOT shifting prior to my two drain/fills and filter change.

Was the Mercon V with around 30,000 miles on it in that bad of shape? Is MaxLife ATF that good?

I am scratching my head here.

EDIT:

I should add the transmission calls for Mercon LV.

 

[crazyoildude]

i use the mercon 5 in my moms 2004 MGM

 

[Rand]

maybe it was too thick?

 

[901Memphis]

Maxlife is actually pretty awesome, and could be more appropriate here if the transmission doesn't like the Mercon V. Some transmissions are picky and some are not.. When you add a tuner into the mix you really have to guess at the fluid needed.

Are there guys running the same mod on the same transmission with Mercon V?

 

[MolaKule]

I don't see how you can complain when you're using a Tuner that provides aggressive shifts.

Does this "canned" tune software allow for the "Learning" of driving habits and different fluids?

 

[ragtoplvr]

a transmission fluid additive is friction modifier for softer no chatter shifts. Companies like Lube Guard sell concentrated additives to improve fluid.

GM has traditionally used different frictions and moderately friction modified fluid. Ford has traditionally used much less friction modifier, although they increased it in Mercon fluid for Dexron compatibility. I am wondering if the shop might have used type F. Used to be good to change a TH400 to racing without opening the valve body, just change fluid.

Rod

 

[MolaKule]

Not all transmission fluid additives provide more friction modifiers, such as LubeGard Red. LubeGard does have HFM "conversion" additives but these are questionable at best.

Quote:
I am wondering if the shop might have used type F. Used to be good to change a TH400 to racing without opening the valve body, just change fluid.


Now "that" is a possibility.

We use "tweaked" Type F for refilling our TH350 and TH400 racing modified trannies.

 

[901Memphis]

The funny thing is I would think that a tuner would provide the best shifts at WOT with the sacrifice in normal driving but I guess not.

Very good thought on the possibility of type have been in the mixture... That type of fluid would certainly cause some different shifting.

 

[turtlevette]

All the teeth knashing over atf. I just used a quart of dollar synthetic mercon 5 to top off the vette. When I'm done with that I'll use the CVT fluid I got for a buck.

 

[MolaKule]

Originally Posted By: 901Memphis
The funny thing is I would think that a tuner would provide the best shifts at WOT with the sacrifice in normal driving but I guess not.

Very good thought on the possibility of type have been in the mixture... That type of fluid would certainly cause some different shifting.


My thoughts exactly.


Quote:
All the teeth knashing over atf. I just used a quart of dollar synthetic mercon 5 to top off the vette. When I'm done with that I'll use the CVT fluid I got for a buck.


Remind me never to buy that car from you with that leaky tranny.

 

[turtlevette]

Originally Posted By: MolaKule
Originally Posted By: 901Memphis
The funny thing is I would think that a tuner would provide the best shifts at WOT with the sacrifice in normal driving but I guess not.

Very good thought on the possibility of type have been in the mixture... That type of fluid would certainly cause some different shifting.


My thoughts exactly.


Quote:
All the teeth knashing over atf. I just used a quart of dollar synthetic mercon 5 to top off the vette. When I'm done with that I'll use the CVT fluid I got for a buck.


Remind me never to buy that car from you with that leaky tranny.

Eventually something might plug it up. Not worried about resale. I'm going to be buried in it.

 

[Greasymechtech]

You used Mercon-V in place of LV and ?????

Wrong spec. Of course any equivalent LV fluid will be an improvement in shift quality(and transmission longevity). No head scratching needed.

 

[PandaBear]

Are there major different friction spec between various spec like Dexron / Mercon / Toyota / Honda / Chrysler ?

I always wonder if there is any huge concern on friction spec and how tolerant most transmissions are in friction.

 

[Whitewolf]

Originally Posted By: PandaBear
Are there major different friction spec between various spec like Dexron / Mercon / Toyota / Honda / Chrysler ?

I always wonder if there is any huge concern on friction spec and how tolerant most transmissions are in friction.


If you want to see just how different some of the OEM fluids are in terms of friction get hold of SAE paper 2007-01-3987. Whilst the fluids tested are only shown as A, B, C,etc (naming names goes against protocol) in most cases they can be identified with very little effort.

 

[901Memphis]

Originally Posted By: PandaBear
Are there major different friction spec between various spec like Dexron / Mercon / Toyota / Honda / Chrysler ?

I always wonder if there is any huge concern on friction spec and how tolerant most transmissions are in friction.


As far as I know chrysler has largest difference in frictional characteristics between the ones you names. A good dex/merc can work for any of the other ones in most cases but dex/merc in an ATF+4 application will typically cause immediate harsh shifts.