4l60e question

[hflwyo]

I have a non Buick related question. I have a 99 Yukon and was driving home Sunday when I noticed the 1-2 shift felt firmer and shorter. I knew something wasn't right. When I got home I got my scanner out and pulled a p1870 trans component slipping and a p0724 brake switch high input. My first question is would a bad brake switch cause the tcc to slip and set a faulty 1870? I replaced the brake switch cleared codes and has drove fine since and no codes back. I used to work at a Chevy dealer about 10 years ago as a mechanic and we used to replaced the valve body for this code due to the bulletin that is out. Is this still the best fix? I know there is the Sonnax valve where you ream out the bore and the Teckpak valve with the o-rings on it are these better fixes? Any advise would be greatly appreciated. I forgot to mention that this is the second transmission I put a SRTA in it about 6 years ago.

 

[TexasT]

I have a non Buick related question. I have a 99 Yukon and was driving home Sunday when I noticed the 1-2 shift felt firmer and shorter. I knew something wasn't right. When I got home I got my scanner out and pulled a p1870 trans component slipping and a p0724 brake switch high input. My first question is would a bad brake switch cause the tcc to slip and set a faulty 1870? I replaced the brake switch cleared codes and has drove fine since and no codes back. I used to work at a Chevy dealer about 10 years ago as a mechanic and we used to replaced the valve body for this code due to the bulletin that is out. Is this still the best fix? I know there is the Sonnax valve where you ream out the bore and the Teckpak valve with the o-rings on it are these better fixes? Any advise would be greatly appreciated. I forgot to mention that this is the second transmission I put a SRTA in it about 6 years ago.

Last time mine had trouble shifting I replaced the throttle position sensor and it cleared it up. Might look into that though mine is a 4l80e.

 

[vaspeed]

Last time mine had trouble shifting I replaced the throttle position sensor and it cleared it up. Might look into that though mine is a 4l80e.

tcc iso valve bore worn in valve body, sonnax makes an updated valve kit, requires reamer.

 

[rag231]

My 99 Suburban has a hard 1-2 shift and I heard it was common on these years. A tranny shop quoted me $3500 for a rebuild. I said that the truck still runs perfectly but the check engine light came on. They say it is an emission problem. I have been driving it like this for 5+ years now.

 

[GBGN1]

I have a non Buick related question. I have a 99 Yukon and was driving home Sunday when I noticed the 1-2 shift felt firmer and shorter. I knew something wasn't right. When I got home I got my scanner out and pulled a p1870 trans component slipping and a p0724 brake switch high input. My first question is would a bad brake switch cause the tcc to slip and set a faulty 1870? I replaced the brake switch cleared codes and has drove fine since and no codes back. I used to work at a Chevy dealer about 10 years ago as a mechanic and we used to replaced the valve body for this code due to the bulletin that is out. Is this still the best fix? I know there is the Sonnax valve where you ream out the bore and the Teckpak valve with the o-rings on it are these better fixes? Any advise would be greatly appreciated. I forgot to mention that this is the second transmission I put a SRTA in it about 6 years ago.

The brake switch is a part of the circuit , if its inop . You will have no lock up. Yes there is an update for the vb .its still the best fix- there is a push in valve that requires no boring ,which usually work but Bore It out and install new reg valve. Easy fix.