My 2005 STR transmission started to slip recently under load on 4-5 and 5-6 along with 3-4 harsh upshift. Checking for codes I found incorrect gear ratio codes which is an indication of something mechanical.

I dropped the transmission pan and valve body to get a limited keek in at the clutches; from what I could see there were burnt clutches. Out with the transmission and onto the bench for strip-down. If like me you don’t have a lift it's not much fun pulling it out.

Found E-Clutch was shot, frictions worn down to the metal and resulting damage on the steels so installed a new set of steels & frictions throughout, new sleeves and overhauled all rubber. Also freshened the valve body with a Sonnax kit and picked up a reman'd TC from Torco in SoCal.

All back together and on the road running very nicely, the only thing I did not do was re-set the TCM adaptations; issue with an expired license on my software stopped me. I have just under 1k miles now, but I think a dealer trip for a re-flash/update is in order to get full advantage.

Cost was just over $1k in parts, 36 cups of tea, 2 fish dinners and 6 bottles of Buckie.

 

Well done....

What ATF did you opt to go with after the rebuild?

 

I went with the Castrol Multi vehicle this time; was running Redline for 70k miles.
Appears to be working well. My only feedback on this is to ensure you have a genuine pan when you replace.

 

This is my kind of post. Informative and by a real DIY'er. Thanks!

 

Nice work!

 

Awesome. Read your initial post and was going to say E Clutch but you already knew it.