As my 03' Mini Cooper S is reaching 43K miles I decided to flush the tranny fluid. After reading all those good reviews on Redline MTL, I put it in. The old fluid was ... totally black without any red in it and new fluid was way cleaner.

As soon as I took it for a drive, I found both gear shifts and transmission were smoother I wondered why I didn't change it

However, after a few days since yesterday or so, I noticed that the car was slow to react to acceleration. My feeling is that acceleration right after upshifting has a big delay, the RPM seems to go up slower than normal, and the actual speed increases even slower. I suspect a synchro problem as the Redline MTL might be too thin and thus slippery for synchro to work properly. Shifting easier might not mean less wear but more wear, and bad on synchro.

How many of you have switched to Redline MTL? Can you give me some inputs? I'm thinking of flushing the fluids again back with OEM fluid as soon as I have an aswer. Thanks!!!

 

I'm not sure what you mean by slow acceleration. The syncros only work while your changing gears; allowing the gear teeth to engage each other at the same speed so they don't grind. Syncros have nothing to do with what happens after car is in gear. You can wear syncros by just pushing the clutch in while moving and start going through the gears. Every time you push the gear lever into a gear, the syncro must work.

Redline also makes MT-90 that's a 90 weight (instead of 80-85 like MTL) when hot.

 

After a gear change is complete (upshift at 4000rpm from 2nd - 3rd), I step on the gas right away , usually under this torque, the car should pick up acceleration right away to continue the previous g from 2nd gear. Then I notice that the rev goes up slower than before with speed going up even slower until it reaches 4000rpm again. Almost feeling that the engine is willing to rev, but there is a slipping in the drive train. Car has 15% pulley and used to pull strong, now I feel a loss of power or a "slow catch" or speed with RPM when launching.

 

This is way interesting cause I bought some MTL and haven't had the time to put it in as yet.

Can't wait for more responses. Though it does seem that the tranny fluid would only slow down the accel. if it was way too thick.

 

The symptoms you are describing have nothing to do with the transmission. Most likely boost-related. Bypass valve sticking?

 

Or, if it was not doing the job of lubricating the gears sufficiently.

Are you sure there is sufficient oil in the tranny? Not that I think you're stupid.

 

I also have some doubt on whether it's transmission related. Since the slow picking up rev occurs after a clutch is out completely and I usually only accelerate when clutch is entirely out.

Bypass valve sticking? Is there a way to check? Maybe it is just coincidence? I just don't want to take it to dealer and then it's the tranny fluid being too thin/slippery.

 

I've heard that too slippery is only a valid concern in Automatic trannys, not manual trannys.

 

It's okay, any clarification is welcome.

I fiilled almost 2 quarts of Redline MTL tranny fluid until it overflew. I haven't seen any leaking on the floor so I assume it's sufficient oil in the tranny.

If I'm losing fluids, isn't it suppoed to make shifting harder? The shifting itself is still smooth and easier than with the original OEM fluid.

 

You are correct - it is a coincidence. A boost gage will probably indicate if the bypass valve is not functioning correctly.

When I was racing showroom stock cars, we used Redline MTL to make the cars go a bit FASTER (reduce friction in the gearbox). However it did not make a difference one could feel. NO WAY 'thin' fluid could slow acceleration down.

 

I called the dealer and will check up 2 weeks later. From all the inputs, I hope it's not the transmission cause, as I have 2 more bottles of Redline MTL at home

Just a side thought, any others that used Redline MTL for an extensive period have any comments on the synchro?

 

Check this out:
http://auto.howstuffworks.com/transmission.htm
This article shows how a manual trans works. Syncros have nothing to do with power delivery between the engine and drive shafts; they only work during the time you are moving the gear lever. Gears transfer the power, and the gear teeth are always engaged.

 

Convinced. Thanks DR61, I'm sure it's something else, probably the bypass valve, that's the first thing my dealer mentioned too.

 

I have had redline in for 45kmiles. No problems with synchros or accelleration. Redline brags about being thin and having the right amount of friction for fast shifts.

 

Are you sure your clutch isn't slipping?

 

Redline MTL works great for my setup, and I'm making mega torque.

 

I really have no idea if this is a good question, as I haven't changed the trany fluid on a MCS. In fact, I'm probably off in left field. But, could he have possibly gotten a drop of oil on the supercharger pulley? Just a thought.