4L60e troubleshooting / rebuild - who in Calgary is good?

[carson blocks]

My brother in law is having transmission problems in his 06 Avalanche. Shifts manually 1-4 but if you start in D or 3 it just revs. Little bit of slippage in first as well, thinking maybe a line pressure issue? Who would you guys recommend to troubleshoot / repair and if necessary rebuild a 4l60e trans?

[firebane]

Are you sure its a 4l60e and not a 4l65e?

[carson blocks]

It could be, but I thought 4l65 was for the 6.0 in Escalades etc. I'm not sure how to tell tbh.

[firebane]

Check the glovebox for the codes and reference.

M30 = 4l60e
M32 = 4l65e

[carson blocks]

It's RPO M30 4L60E

[Twin_Cam_Turbo]

Sounds like a broken sprag maybe if it will manually shift starting in 1?

[carson blocks]

Any referrals for good honest trans shops?

[iron_man888]

avoid Quality Transmission... they botched our rebuild and refused to fix their mistakes