hello! my truck has a 4l60e and today it got randomly colder then the past couple weeks here in canada and the temperature was around -20 celcius which is -2 fahrenheit i believe.
i remote started the truck and got in 2 mins later and started driving, it reversed fine and was normal for the first 30 seconds, when i came to a complete stop and left the parking lot, the revs would go up but the truck wouldnt move so i shifted into neutral and back in drive and same thing, revs would go up no movement. i then shifted into park and back into drive and it was good to go but i noticed it wouldnt shift, it seemed to be stuck in gear 1/2 but my speed was only 40km/h ish so i pulled over into a parking lot and left it running while i went inside a store and came back after 10 mins and everything was perfectly fine, shifted good and normally. the past weeks hasnt been that cold so i have not noticed this behavior in a while.

about 3 weeks ago i had my fluid changed and the old fluid was still red, and did not smell burned or anything, i did the pan drop filter change and the cooler line fluid exchange. after the fluid change i have been monitoring the level and no leaks and its at hot on the dipstick when the tranny is hot.
i noticed about 4-8 weeks ago this same thing happened but it only happened when the temperature was -40 celcius which is -40 fahrenheit as well, and it made more sense when the temp was that cold because thats pretty cold but if it starts happening now at around -20 celcius then thats gonna suck for me because canadian winters are always around this temperature.


what do you think i should do? is this just due to an old transmission (245,000km on it) or is there something loose/needs to be replaced? the new fluid that went in was the ac delco dexron vi


thanks!

 

Dump in a can of TransTune

 

I'd look at a way to pre-heat the trans fluid if you are encountering those sort of low temps which are below the transmissions operating temperature.

 

Have you done the external cooler fix yet? If so did you use the thermal bypass? If not you should get one and put it in-line.

 

if you are not getting 3/4 shift your 3/4 shift piston might need replacing that would require a rebuild. common issue is the rings shrink with age and the cold compounds the issue further letting the built up pressure past the seals. very common on 4l60/4l65 family transmissions