Mobil 1 Syn ATF... Altered shift points?

[Flying_A]

Hey all,
As the title says, has anyone experienced altered shift points in using a synthetic ATF where Dex III is recommended?

The problem I'm having in an 03 Land Rover Disco SE7 w/ 85k, is in 4th gear. Goes to highway cruising mode (solenoid in torque converter that almost makes 4th gear into 2 separate gears) at 37mph and bogs pretty badly.

I'll be dumping it for a conventional ATF this week. Just would like to know if anyone has experienced this in other cars.

 

[daves87rs]

Strange.....

 

[Rand]

Does that vehicle have a learning transmission.. you might want to try disconnecting the battery for 10min and see if that helps.

 

[440Magnum]

Can't imagine that the fluid would be responsible for altering shift points. It might conceivably make the torque converter lockup clutch engage harder or shudder if the transmission calls for a friction-modified fluid. But you say its spec'd for Dexron III, so M1 ATF should be just fine. Odd.

 

[Flying_A]

Originally Posted By: Rand
Does that vehicle have a learning transmission.. you might want to try disconnecting the battery for 10min and see if that helps.


I did a head gasket job on it a few months back with the battery disconnected for over 4 weeks. It was doing this before and after the job was done.


Originally Posted By: 440Magnum
Can't imagine that the fluid would be responsible for altering shift points. It might conceivably make the torque converter lockup clutch engage harder or shudder if the transmission calls for a friction-modified fluid. But you say its spec'd for Dexron III, so M1 ATF should be just fine. Odd.


The tranny seems to operate fine other than this two speed 4th gear thing. 1st-3rd is fine. It started as soon as I switched the atf out with M1 syn.

 

[lexus114]

I would switch back to what you were using before this happened. Hopefully it will go back to being okay again.

 

[440Magnum]

Originally Posted By: Flying_A

The tranny seems to operate fine other than this two speed 4th gear thing. 1st-3rd is fine. It started as soon as I switched the atf out with M1 syn.


That really does sound like the transmission is expecting to have a friction-modified fluid and the TCC is just grabbing instead of smoothly engaging or going into a partial-lock mode. Modern (post 1990) transmissions do very complicated things with the TC clutch, locking it partway in some gears, and the slowly locking it as speed builds in final drive so it almost acts like a continuously-variable tranny. To do that most of them use friction-modified fluid to keep the TC clutch from grabbing or chattering. (like Mopar ATF+ 4, but there are many others).

 

[Flying_A]

Originally Posted By: 440Magnum
Originally Posted By: Flying_A

The tranny seems to operate fine other than this two speed 4th gear thing. 1st-3rd is fine. It started as soon as I switched the atf out with M1 syn.


That really does sound like the transmission is expecting to have a friction-modified fluid and the TCC is just grabbing instead of smoothly engaging or going into a partial-lock mode. Modern (post 1990) transmissions do very complicated things with the TC clutch, locking it partway in some gears, and the slowly locking it as speed builds in final drive so it almost acts like a continuously-variable tranny. To do that most of them use friction-modified fluid to keep the TC clutch from grabbing or chattering. (like Mopar ATF+ 4, but there are many others).


I see... Thanks for the breakdown. Would you recommend going to a standard Dex III (recommended fill) or a M/V forumla, may have more friction modifiers in it to help aid the TC to engage properly?

 

[440Magnum]

Originally Posted By: Flying_A
Originally Posted By: 440Magnum
Originally Posted By: Flying_A

The tranny seems to operate fine other than this two speed 4th gear thing. 1st-3rd is fine. It started as soon as I switched the atf out with M1 syn.


That really does sound like the transmission is expecting to have a friction-modified fluid and the TCC is just grabbing instead of smoothly engaging or going into a partial-lock mode. Modern (post 1990) transmissions do very complicated things with the TC clutch, locking it partway in some gears, and the slowly locking it as speed builds in final drive so it almost acts like a continuously-variable tranny. To do that most of them use friction-modified fluid to keep the TC clutch from grabbing or chattering. (like Mopar ATF+ 4, but there are many others).


I see... Thanks for the breakdown. Would you recommend going to a standard Dex III (recommended fill) or a M/V forumla, may have more friction modifiers in it to help aid the TC to engage properly?


If the owner's manual calls specifically for Dex III then that's what I'd try. Problem is, most fluids today are Dex V and claim backward compatibility to Dex III, but there are some subtle differences (Dex V is slightly lower viscosity, IIRC). But I think you can still find true Dex III.

Its also possible that you had some internal failure coincidental to changing the fluid, or if its a computer-controlled transmission it may be in the re-learning process as others have mentioned. What manufacturer and model/type is the tranny in this vehicle? Some googling makes it look likely that its a ZF of some flavor.

 

[Flying_A]

Originally Posted By: 440Magnum
Originally Posted By: Flying_A
Originally Posted By: 440Magnum
Originally Posted By: Flying_A

The tranny seems to operate fine other than this two speed 4th gear thing. 1st-3rd is fine. It started as soon as I switched the atf out with M1 syn.


That really does sound like the transmission is expecting to have a friction-modified fluid and the TCC is just grabbing instead of smoothly engaging or going into a partial-lock mode. Modern (post 1990) transmissions do very complicated things with the TC clutch, locking it partway in some gears, and the slowly locking it as speed builds in final drive so it almost acts like a continuously-variable tranny. To do that most of them use friction-modified fluid to keep the TC clutch from grabbing or chattering. (like Mopar ATF+ 4, but there are many others).


I see... Thanks for the breakdown. Would you recommend going to a standard Dex III (recommended fill) or a M/V forumla, may have more friction modifiers in it to help aid the TC to engage properly?


If the owner's manual calls specifically for Dex III then that's what I'd try. Problem is, most fluids today are Dex V and claim backward compatibility to Dex III, but there are some subtle differences (Dex V is slightly lower viscosity, IIRC). But I think you can still find true Dex III.

Its also possible that you had some internal failure coincidental to changing the fluid, or if its a computer-controlled transmission it may be in the re-learning process as others have mentioned. What manufacturer and model/type is the tranny in this vehicle? Some googling makes it look likely that its a ZF of some flavor.






Alright, I'll go for the standard Dex 3 and see what happens... I doubt it was a coincidental failure, the trannys in these are pretty tough (ZF trans btw). Most last 200k+ without issue. I appreciate your insights though! I'll let you guys know what happens.

 

[kozanoglu]

Have you tried Valvoline Maxlife ATF?

 

[eagle23]

Before you dump the M1, try a bottle or two of Lubegard Red or Platinum. Check their website for which.

They are remarkable, well recommended additive packs with terrific results (personal experience plus many other BITOGers).

I get mine from NAPA but check your local sources.

You have little to lose and a LOT to gain by not dumping the expen$ive M1 when maybe all it needs are the proper friction modifiers. If it doesn't work, go ahead with the Maxlife.

 

[Boss302fan]

I doubt its the ATF but if you change it, I would try Maxlife ATF without any additional additives. Lubegard is a really good product but I would not use it before first trying just Maxlife...

 

[Ken2]

A couple of clarifications:
"using a synthetic ATF where Dex III is recommended?"
The choice of base oil (conventional or synthetic) has nothing to do with the Dexron-III performance. That is about the additive package (and the conventional or syn base oil must be suitable, of course). ExxonMobil says that their "Mobil 1 Synthetic ATF is recommended by ExxonMobil for use in applications requiring: GM Dexron IIIH" (the latest version of Dexron-III before it was discontinued). Synthetic or conventional base oil only gives longer fluid life, and maybe better performance when very hot or very cold.

There is no Dexron-III on the market. It was discontinued a couple of years ago. Actually there is--under the label of the Allison TES-389 spec, not the Dexron-III label.

I think your problem is internal in the transmission, not the fluid.

 

[ron350]

Makes me wonder how AC Delco still gets away with putting Dexron III on their label.

 

[AzFireGuy79]

Old stock. I bet if you looked at the production dates they would be prior to the cutoff with DEXRON III license expiring.

 

[Flying_A]

I will probably try the Maxlife but have access to Shell products quite easily,any highly recommended SOPUS products?

 

[meep]

read original post, skipped to the end.

if the M1 has a different friction coefficient, AND the LR is using a partial engagement, what's happening is that the partial lockup is now becoming a complete, or more complete lockup.

I experienced same in another vehicle. your AT wants a more friction-modified fluid. you can correct this by adding SMALL, CAREFUL amounts of LubeGuard Black. just a little at a time.

 

[Flying_A]

Originally Posted By: meep
read original post, skipped to the end.

if the M1 has a different friction coefficient, AND the LR is using a partial engagement, what's happening is that the partial lockup is now becoming a complete, or more complete lockup.

I experienced same in another vehicle. your AT wants a more friction-modified fluid. you can correct this by adding SMALL, CAREFUL amounts of LubeGuard Black. just a little at a time.


Others have suggested the Lubeguard Red and Platinum... Why the black over the red or Plat? And when you say "a little at a time", how much is a little?

 

[meep]

Red and Plat are designed to fortify an additive package, but not to alter it. Black actually alters it.... for example allows use of a Dex in a honda z-1 application (I did this with mobil 1 ATF in an 02 accord and it did exactly what it was supposed to).

The thing is, it doesn't take much. the more you add, the less the grabiness. the bottle may suggest something like 1/2oz per quart??? less? (READ the bottle, not my memory!) the nice thing about this, is you can add a small amount at a time until you get it where YOU like it. (taking test drives between adding a spot more). So yes, by small amount, we are talking a total of a few ounces.

M