My 06 S has nearly 100k on it.
One of the first things I did was to start adding fresh type IV ATF to the transmission (after draining of course).
Problem is that the 2nd to 3rd shift was a bit abrupt and after the first fluid change (about 2 qts) it seemed like shifts were getting smoother.
However, after adding Redline ATF the 2nd to 3rd shift was smoother but now seems to slip a bit under load.
This is all happening when the car is at operating temperature.
I'm wondering if I should prepare myself for a new trans???

 

Are either of those the equivalent of the required JWS3309. Did you follow the flush fill procedures?

It's not like filling a crankcase. Trans fluid needs to be warmed up before filling and running through the gears is necessary during filling procedures....There are 3 plugs for the fluids, a fill, an overflow and drain plug. Overflow is used for fill reference.

 

Yes, both are JWS3309 or equivalent.
A transmission shop did it for me.

 

Then take it back or find a MINI dealer.

 

It wasn't the shop's fault.
The trans was having issues before I took it there.
I don't think the fluid was every changed before and damage was done already.

 

Drop the pan, change the filter, and use redline. Make sure trans is up to temp and run through the gears if it helps, change again in 6mo. It might take 2 or 3 changes to flush it out. It's much cheaper then a trans. Hope it works

 

That's what I plan to do.
But that gasket is ridiculously priced and so is the filter!
My Mercedes filter and gasket are probably 1/3 the price.
I just hope I'm not throwing money away on a bad trans.
I'll keep you folks posted.
Thanks!

 

The filter isn't so bad, but the gasket is crazy. No one sells it but mini, you should also put in a new check fluid plug. Hey 3 fluid changes is cheaper then 4000.00 for a trans. Good lic

 

Thanks for the suggestion on the check fluid plug.
Will do.

 

Your problem is very likely the valve body. Do a search to find the huge thread on here. A reman valve body swap with cost you about $1500. I wouldn't bother with the additional fluid changes as this point, save your dollars and fluid for the VB swap.

 

Thanks!
I'll search around.

 

It does sound like your valve body is the problem..just as stated above... I would highly recommend changing your fluid with a synthetic ATF.. That really is key to have these type of transmissions last.. Factory fluid they use is nothing fancy and it is not at all a synthetic.. good luck!!!

 

Looks like I'll be checking out the RevMax rebuilt body.
Definitely going to us Redline ATF to refill.
Thanks

 

Alrighty, here's an update to this thread.
Changed out the valve body sourced from RevMax.
Shifting is MUCH better and so are the downshifts.
But one weird thing is that when cold, the 3-4th shifts holds past 3k when under a bit of load.
Any ideas?
Also, should I reflash the transmission ECU? Not sure why but I think I've read this somewhere.

 

Thanks for the follow up.
So it's not necessary to reflash the ECU?

 

thanks!