Alright so my car is spending the night at the shop as it's getting a transmission swap. I have 0 oil as I wasn't expecting to swap the transmission until this weekend but it was bumped up to today. Dealership doesn't sell tranny fluid as they only have containers. My luck, no autoparts stores (that I'm aware of) sell 75w80 gear oil.

So, can I run 75w90 gear oil for the weekend until mon-wed when I can have the fluid switched out with the stock stuff, or redline mtl again...

 

As long as it's not GL-5, you'll be ok. GL-5 (hypoid oil) and brass syncro's don't go together very well.

 

Does it have to be synthetic?? Getting the car back today and need a temporary trans fluid as I'm picking up the MINI MTF94 later today or tomorrow (after I get the car back)...

 

Not to resurrect a dead thread but just to add information for those searching for answers like I was. Direct instructions from a Lucas Oil Rep are that you can use a 50/50 mix of their 75W-90 Synthetic Gear Oil and Synthetic Oil Stabilizer and that will dilute the GL-5 additive package down to GL-4 standards. Do with that information what you will.

 

I run 75w-90 Eneos its been fine just like that for a very long time.

 

Not gonna mess with mixing anything. OEM MTF-94 for my '10 MCS.

 

GM Syncromesh works fine and you can get it at any parts store. I use it in my car with no issues.

 

I don't want to resurrect a dead thread, but I need a little help and hopefully this will get a little visibility.

Motul MotylGear 75W90 meets GL-5/GL-4. Is this safe? I'm asking because a vendor here sells it specifically for the R56S. I bought 2 liters of it and replaced my gear oil last October. Now my transmission pops out of 6th gear when it is under load. Didn't have a problem before, and didn't notice it until recently because I didn't do much highway driving. It is pretty random, sometimes it holds, sometimes it doesn't and it happens way more often in sport mode. Made 6th totally worthless last weekend at Road Atlanta.

 

@scotty_r56s
Are you still dealing with your 6th gear pop? i recently have this issue under load about 70mph, not in S mode. I ordered some Redline 75-80 from ECS to change out before I take it to a shop.

Thanks

 

Sorry for the late reply. Unfortunately, there has been no change to my issue. When I'm back in town I plan on inspecting the motor and transmission mounting points and possibly removing the BSH solid mount and going back to stock to see it that is the issue.

 

Sorry for the late reply. Unfortunately, there has been no change to my issue. I replaced the Motul fluid with Redline 75-80.

When I'm back in town I plan on inspecting the motor and transmission mounting points and possibly removing the BSH solid mount and going back to stock to see it that is the issue.