MTF OCI

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What’s the general thought for a change interval on a manual transmission ? My 2010 Lance’s warranty book says 2 years/ 30,000 mile (48,000 km). I’m convinced this is for the automatic, which shares the same warranty book. The last time I changed it the fluid looked brand new, I replaced it with Redline MTL. I’m coming up on the change interval and am wondering if changing it again is a waste of time. Thanks.
 
On synthetic GL-4+ fluids, I recommend 50,000 km. Beyond that you really don't know how much dirt, wear materials, or whatever is circulating. Since it is only 2 or 3 its, no big deal.

For anyone still using the old formulas, I would change out as soon as possible.
 
Thanks for the input. I did notice it shifted better the last time I changed it, I had just assumed that was the switch from Diaqueen to Redline. It only takes 3 qts, so I guess for $50 I may as well. The spec is for GL3 but the Redline I put in is GL4.
 
I generally changed when shift feel degraded.

In my E30 with redline, it was repeatable. When I went to Amsoil the feeling didn't change. I'd wait until you feel a change, then fill with Amsoil MTF.
 
Most manual transmissions never require a fluid change. Manual transmissions don't get as hot as automatic transmissions.

The only mfr I know of that specifies a MTF change is Honda, but their MTF is basically motor oil, and in fact, they used to specify just motor oil until they made their own MTF in 1996, and even then they say motor oil can be used as an alternative.

A few cars say to replace the fluid around 8000 miles, then never again.
 
I've no idea but the last time I changed the fluid, merc/dex3, it was about as dark as an auto transmission's fluid after around similar mileage (40K). It also washed out some small specks of metal, which I'm guessing is from the synchros. Then again, mine uses ATF and not gear oil and I just use the cheapest merc/d3 I could find. My owner's manual doesn't specify manual transmission fluid change; it only tells the owner to check that it's at proper level by pulling the fill plug. I'd still change it on a periodic basis though.

I couldn't tell any improvements in shift quality after a fluid change, to be honest.
 
50K has always been my # if filled with MTL. That is one fine lube. It cures all sorts of bad shifting issues
smile.gif
 
Originally Posted By: ruhroh
It also washed out some small specks of metal,

I couldn't tell any improvements in shift quality after a fluid change, to be honest.


I change it every 10,000-20,000 just to get the flecks out (I do a lot of towing)

I DON'T TOSS IT, THOUGH.....

It goes back in the bottles so the grit settles to the bottom...
and then goes right back in again on the next change.
You'd be surprised what settles out!
 
i changed the fluid in my truck for the first time at 240k. What was originally red ATF came out black. Didnt really make a difference in shifting. Ive never changed any of the fluid in my FWD mazdas, although I probably will at 50k which is coming up real soon.
 
I changed the fluid for the first time at 150k in my little ECHO commuter car with Amsoil MTG. No difference in shifting whatsoever.

Changed again at 200k (with more Amsoil) and the fluid still looked very good.

I don't think I'll change it again for a long time.
 
Originally Posted By: slacktide_bitog
Most manual transmissions never require a fluid change. Manual transmissions don't get as hot as automatic transmissions.

Why would it be so , as they have fewer components IINM ?
..... or sump volume matters ?
 
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Generally all gearboxes (AT/MT) nowadays are "sealed for life"...

But since I personally dont belive in that nonsense...I am changing MT fluid @aprox 90kkms (AT fluids @aprox 60 kkms)
 
Originally Posted By: JHZR2
I generally changed when shift feel degraded.

In my E30 with redline, it was repeatable. When I went to Amsoil the feeling didn't change. I'd wait until you feel a change, then fill with Amsoil MTF.

I struggle with the Amsoil MTF. Neither my Lancer nor my Outlander have recommended MTF or Gear Oil when using their vehicle recommendation tool. The Lancer calls for 75W80 GL-3. So the MTG should fit this, I can’t figure out why it says “no recommended Amsoil product”. The Outlander calls for 85 W and 90W GL5 so the severe gear 75w90 should work but I get the same message.
 
Originally Posted By: JHZR2
I generally changed when shift feel degraded.

In my E30 with redline, it was repeatable. When I went to Amsoil the feeling didn't change. I'd wait until you feel a change, then fill with Amsoil MTF.



Fluids do shear and additives do get degraded so I think that is a good rule to follow.

BTW, MT's can get very hot because they are conductively coupled to the back of the engine.
 
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