05 Yukon/New guy

[Skipper50]

SE Texas, '05 Yukon XLT 1500

 

[NathanJax]

 

[Fosscore]

Welcome.

 

[Skipper50]

SE Texas, '05 Yukon XLT 1500

Replaced rear seal and oil pan to stop leakage. Tranny was dropped for this.
Following reassembly the transmission will not shift.
Found and replaced failed brakelight switch.
Still not shift.
Fluid levels are good.
Can't find anything impeding shifting.
I'm thinking the TCM lost it's mind.
Suggestions?

 

[Miami-Dade]

Welcome from Miami&Queens NY!

 

[swathdiver]

Replaced rear seal and oil pan to stop leakage. Tranny was dropped for this.
Following reassembly the transmission will not shift.
Found and replaced failed brakelight switch.
Still not shift.
Fluid levels are good.
Can't find anything impeding shifting.
I'm thinking the TCM lost it's mind.
Suggestions?

If the torque converter moved and is not clicked in all the way then it has to come out. Let's ask Nick: @NickTransmissions

 

[NickTransmissions]

Replaced rear seal and oil pan to stop leakage. Tranny was dropped for this.
Following reassembly the transmission will not shift.
Found and replaced failed brakelight switch.
Still not shift.
Fluid levels are good.
Can't find anything impeding shifting.
I'm thinking the TCM lost it's mind.
Suggestions?

It won't upshift from first gear? If so, check to make sure your vehicle speed sensor is plugged in and wire not cut/frayed.

 

[RAMurphy]

Welcome to this great forum.

 

[OR VietVet]

Welcome to the forum from Oregon.

 

[rockola1971]

Replaced rear seal and oil pan to stop leakage. Tranny was dropped for this.
Following reassembly the transmission will not shift.
Found and replaced failed brakelight switch.
Still not shift.
Fluid levels are good.
Can't find anything impeding shifting.
I'm thinking the TCM lost it's mind.
Suggestions?

Need more info about this "tranny will not shift"? What do you mean? Wont mechanically shift into (D) or goes into gear but wont shift past 1st gear? Does manual 1 or 2 work? Did you get your shift cable properly attached to tranny and not get the adjustment out of wack at its adjuster?