Chevy & GMC Vans

Ok so when I'm driving at about 60mph this thing will just down shift for no reason and then shift back into OD does anyone have any clue as how to fix this? Its a 92 Astro also thanks.

the clutches in the torque converter might be giving up the ghost, or the torque converter lockup solenoid might be going bad.
First thing is check the wiring to the tranny and the connector to make sure all that is good. bouncing along with a bad connection could cause the tcc solenoid to kick in and out, but then you'd probably notice your speedometer jumping around as well.
How many miles on the transmission?

Not a clue on miles #-o It has a custom sheet metal dash with aftermarket gauges and what not.
Where is this solenoid and how hard is it to replace and is there anyway to test it? Also the speedometer doesn't jump at all.

You can get to the solenoid by dropping the pan on the transmission. If you go to rockauto.com they have an image of the part so you know what you are looking for. they have it listed as a "control solenoid" under the transmission parts section.
As for testing it, I don't know the answer to that.
Likely someone on the site does though...post up brethren, need some hep here.

Check the TCC switch that is on the brake pedal. If it is adjusted to loose it will be touchy, and unlock the converter with the slightest touch or bump/dip in the road. This can also cause the cruise to disengage if the switch for that is too touchy. Also be sure that the pedal is returning and stays 'up'.

Ok I will check that out because the cruise control doesnt work either.

rlsllc wrote:Check the TCC switch that is on the brake pedal. If it is adjusted to loose it will be touchy, and unlock the converter with the slightest touch or bump/dip in the road. This can also cause the cruise to disengage if the switch for that is too touchy. Also be sure that the pedal is returning and stays 'up'.

Just a liitle update after little adjustment problem is gone Thank You for the advice.

good to hear the fix was so easy