Side effect of bleeding clutch, smoother shifting - The Unofficial BMW M5 Messageboard (m5board.com)

phid_bombadier · 5th May 2007, 01:25

I had changed to Redline MTL and put in a UUC SSK a while back and I had difficulty shifting into 2nd when the car was cold. I've experienced this before due to diff fluid and increased shifting effort due to the SSK.

I was waiting for my Clutch install to change out the tranny bushings as this has contributed to this in my E36M3 back in the day.

After flushing the brake and clutch fluid I've noticed that I'm not having trouble shifting into second now...maybe every once in a while but not almost every time like before.

My clutch/brake fluid was pretty dead. The color of thick olive oil with some milkyness to it. Now it's just pretty, translucent blue!

I suspect I wasn't getting full actuation of the slave cyl so the clutch wasn't disengaging 100% and overworking the synchros. But I'm just guessing...

So if your shifting is tough and you haven't changed your fluids in a while it might be worth a shot, and you should take care of the fluid either way.

--Mike

Lscman · 5th May 2007, 16:01

I'd say your assessment is right. The clutch was probably dragging some and eating the synchros. The clutch/brake fluid needs changed yearly, unless you want to risk it. Old fluid can cause corrosion in the clutch slave or seal leakage that can lead to blowby and reduced piston actuator movement.

The clutch, tranny and ABS brake system are quite pricey and neglected fluid is not a good idea. It's hard on seals, valves and corrodes metals used throughout.

Lscman · 5th May 2007, 16:04

The redline MTL is not optimal, IMO. The D4 ATF seems to work better than MTL in this application and the RP Synchromax is the best for shift quality and synchro action.

The OEM fluid works fine under most conditions, but it's a bit thicker and leads to stiffer shifting when cold.

phid_bombadier · 5th May 2007, 19:55

I typically use D4 ATF in BMW manual trannies but I decided to go with MTL this time because I remember reading that MTL was a better lubricant. I'm going to go with the UUC Cocktail next weekend when I get my clutch/flywheel swapped out.

This was the second to last of the "change all fluids" when I get a used car program. So hopefully it wasn't left too long in the previous state...

Thanks for the input!

--Mike

Lscman · 6th May 2007, 00:36

Quote:

Originally Posted by phid_bombadier

I typically use D4 ATF in BMW manual trannies but I decided to go with MTL this time because I remember reading that MTL was a better lubricant. I'm going to go with the UUC Cocktail next weekend when I get my clutch/flywheel swapped out.

This was the second to last of the "change all fluids" when I get a used car program. So hopefully it wasn't left too long in the previous state...

Thanks for the input!

--Mike

That Redline UUC mix you mention is heavier like the OEM Getrag gear lube. A thicker viscosity will provide better gear wear resistance.