have a Chevy 1500 two wheel drive with a 4.3l v6 Vortec with a 4l60 automatic transmission. problem is overdrive will spin out at 32 mph. Changed fluid and filter with same result, checked all fuses all good changed transmission and still have same result spins out at 32 mph. really lost on this one, was told wire problem but no clue where to look. Need some good feed back that could help please thanks.

 

I am a little confused, you say overdrive spins out at 32mph?? By this do you mean it loses friction and engine revs?? My first question would be why is the transmission in OD at 32mph?? And if it is, (and it certainly may be) that is when the transmission will encounter the most resistance to rotate (i.e. like trying to pedal from a stop on your bike in the highest gear). If this is the case, there simply isn't enough pressure and/or friction to hold the gear. It may simply be worn. Good luck.

 

transmission slips in third and overdrive

 

transmission slips in third and overdrive

 

Very old thread here. Wonder if the problem was resolved, and what the problem was.

 

 

Same here. My 1997 Sierra started slipping. A mechanic friend said not to replace the fluid at that age. What I did was drain about a pint of the old fluid and add some new. Not a perfect fix but it helped. Autozone has a transmission for $3000 but this old a truck isn't even worth that much.