Any Harm Running Amsoil MTF over ATF+4

[JSRT4]

Hello, I posted recently inquiring about a better fluid for a 6 speed Getrag manual transmission - 6MT, on my caliber srt4, which uses ATF+4. I think I've settled upon using Amsoil's MTF 5w-30 hoping to get a better shifting tranny from it, and perhaps a bit better protection given the power of the vehicle. Before I take the plunge I wanted to ask if there could be any harm from running the Amsoil MTF in place of ATF+4 ?. The Amsoil will be a tad thicker fluid. I personally can't see any downside to it, but I thought I'd ask just in case. thanks for any replies.

Joey

 

[bmwtechguy]

Try it and see how it shifts. Are you out of warranty? I have replaced ATF with that fluid and had good results such as smoother shifts, but I wonder how yours will shift in the dead of winter at -20F? Let us know how it does. Our cars never see those cold temps here.

 

[99]

ATF+4 is a pretty good trans fluid.

 

[JSRT4]

Originally Posted By: 99
ATF+4 is a pretty good trans fluid.


Even in manual transmissions ?, I think it is a pretty good fluid for auto trannies, I just never warmed up to the idea of it being used in manual trannies. Call me old school I guess.

 

[JSRT4]

Originally Posted By: bmwtechguy
Try it and see how it shifts. Are you out of warranty? I have replaced ATF with that fluid and had good results such as smoother shifts, but I wonder how yours will shift in the dead of winter at -20F? Let us know how it does. Our cars never see those cold temps here.


Thanks I think I will end up trying it either way. The car is brand new, lots of warranty to go. I probably won't be driving it much in winter months, mostly spring, summer and fall months, so it shouldn't see temps anywhere near freezing. With Amsoil being fully synthetic it might be fine in cold temps though.

 

[Pablo]

There is nothing physical that I know of that absolutely requires ATF+4 in that transmission. Surely MTF is a more viscous fluid, and yes on a 0°F morning, ATF+4 will be thinner, but it's not like MTF will be solid. (pour point is about -49°F) OTOH MTF has the correct FM's, great EP/AW protection and will have the necessary film thickness to protect.

As for your warranty, you will be on your own.

 

[Doug Hillary]

Hi,
JSRT4 - There are very good Technical reasons for staying with the manufacturer's recommended specification - an ATF+4. Most of these are only known to BMW!

Many German gearboxes have used ATF as their lubricant for several decades MB and BMW (in their own or Getrag & ZF boxes) are but two

You would be much better served to use a modern fully synthetic ATF+4 fluid than the Amsoil MTF product mentioned!!!!

 

[Audi Junkie]

I would stick with ATF+4, no doubt. Especially in extreme conditions.

 

[mechtech2]

The Amsoil may offer better protection and shifting.
Just because BMW and other Mfrs. stock only one fluid for auto and manual transmissions, and also maybe for power steering and transfer cases, doesn't mean it is the best fluid. Only suitable.

 

[Donald]

What does the Amsoil website list for that vehicle and tranny? I would use what Amsoil lists.

 

[JSRT4]

Amsoil does not have a listing for my engine/tranny, likely too new for their application listing.

Thanks for all of the replies everyone, I do appreciate it. In terms of temps this tranny will never likely see temps colder than 32 degrees F ( 0 degrees C).

I have driven manual trannies with ATF+4 fluids in the past, and I found them to be harder to shift as temps got very hot, in summer conditions. They seemed find in cooler spring and fall months but not so great at really hot temps. Seeing as my car will put out alot of heat through the engine and tranny system due to the turbo inclusion, I can envision this also being the case on this vehicle.

I see a lot of BMW people complaining of poor shifting trannies in recent times and most are criticizing the ATF fluid and overly long service intervals.

 

[Audi Junkie]

What about AMSoil ATF?

 

[Pablo]

Originally Posted By: Audi Junkie
What about AMSoil ATF?


It's what they recommended in 2007. Nothing published for 2008.

With a viscosity of 6.8 cSt, it's moving in the wrong direction for the OP.

 

[JSRT4]

The 6mt six speed manual is an all new tranny for the caliber in 08, but given it's use of atf+4, I wouldn't be surprised if Amsoil recommended their ATF for it once they get their application list updated. I would prefer something a little thicker than their ATF though, to give an extra margin of safety in hard driving conditions.

 

[Audi Junkie]

That's whole "extra margin" thing seems to always not hold up to scrutiny, especially in stock applications.

 

[bmwtechguy]

They will recommend their ATF (albeit a universl product), same as he manufacturer, an ATF.

 

[lazaro]

I have been using the MTF 5w30 in a MTX 5 speed box for 3 years now, great stuff, last alot longer than the ATF in my car.
I see no issues using it in a Getrag

 

[unDummy]

Lazaro, I would think that the Miami weather pattern would benefit from upgrading to a thicker MTF/MTL over an ATF. Hotter climates or weaker transmissions, can benefit from a mildly thicker fluid.

JSRT4, I would expect that the cold weather habits with the MTF/MTL would not be as friendly as with ATF+4. This is for you to test. Being full synth should help, along with a little shearing over time, with initial and winter shifting.
Your northern location has cooler average temps and cool means thick.

Amsoil MTF and Redline MTL, IMO, are excellent manual fluids. They will work well in place of ATF, especially in warmer climates.

There is a UOA with Redline D4 in a manual that came out excellent. I would try that ATF 1st. One would think that the Redline's C+, racing, and hightemps, would also be appropriate here.

Royalpurple also has a SyncrhoMax fluid that is at the ATF viscosity that should also be considered.

Amsoil ART or ATD are other options.

I don't foresee any real downsides to any of the above mentioned fluids. But, ATF+4 protects extremely well. And shift habits can be negatively affected by a too thick fliud.
The best fluid for you will require trial and error. Just consider your average weather conditions when stepping up in viscosity.