Picked up a used trans. Need help refreshing it

zmon1300

Corporal
Nov 3, 2016
181
114
0
Chicagoland
Ride
'10 335xi
Hey guys,

My current trans on my 93k mile 335xi does not hold 5th gear anymore. I abused that trans for about 50k miles. It was either on Alpina flash or xHP stg3 OTS tune. I recently picked up a 44k mile trans from a local part out and got a trans cooler core and lines. I wanted to ask what things I need to do to refresh it make it ready for 600awhp?

I did some researching and came up with the following things that I should replace:
Trans pan/filter
trans pan/filter gasket
Trans oil
Mechatronic sleeve]
Sonax Zip Kit

Are there any other things I should replace to get it ready for my car? Also, what trans fluid would be best in this case? What kind of inline T-stat should I get for the trans cooler?

Thanks
Z
 

doublespaces

Administrator
Oct 18, 2016
9,303
4,331
0
AZ
Ride
2009 E93 335i
The factory Pentosin or whatever it is seems to always be the best fluid from what I've seen. For the T Stats you've got several options, but a lot of guys go with the Improved Racing 90/10 tstat.
 

zmon1300

Corporal
Nov 3, 2016
181
114
0
Chicagoland
Ride
'10 335xi
FCPeuro sell a mechatronics service kit with all fluids and seals needed for servciser the job. Your list is missing lots of things!!!

I looked up the service kit on FCPEuro which was $385. I bascially have all those parts already. But instead of plastic sleeves, I found a few of them that are aluminum which should help with longevity. The pan, filter, gasket, D4 fluid, and the sleeve bits I already have ready.
 

zmon1300

Corporal
Nov 3, 2016
181
114
0
Chicagoland
Ride
'10 335xi
The factory Pentosin or whatever it is seems to always be the best fluid from what I've seen. For the T Stats you've got several options, but a lot of guys go with the Improved Racing 90/10 tstat.

Yeah I picked up a I.R. 165 Tstat for the trans and a 210 Tstat for the oil cooler