Chevrolet s10 4.3

Only use a Dextron type ATF for a GM transmission.


I found one that had this spec, hope it’s good?
It’s going well today, when I changed the oil and filter in the box, I found a crack in the radiator, in one end, seems to go into the oil cooler hole.
GM Dexron IIIH


As long as it says Dextron III or greater it will be fine, generics that have approval rating of Dextron is also acceptable.

I think the only insensitive GM automatic is the TH400, you could put pure hydraulic fluid in it and it will still run.


Thanks Cody, this one was cheaper too.


A little cleaning, now that I don’t have a cooler.
Is much more crap on the left bank than the right, does it suck in different amounts?
Why does the map sensor break, have 2 broken now?


One bank might have more baffling in the manifold than the other and it could cause soot to drop more often. Just a guess.

Jan if you don’t have the radiator cooler I would suggest looking for an external cooler for the transmission.
Though in your colder area, the radiator portion actually helps warm up the transmission fluid faster and then keep it at a stable temperature.

You should avoid letting the transmission fluid get hotter than 225°F. With my stock system in my Sierra 1500 I’ve never gotten hotter than 200°F even with town traffic. In my 1976 GMC C15 I have a Radiator and External cooler but that is because I only have 3 speeds and I want to go easy on the fluid.


Thanks for the tip, Cody I ordered a new radiator, I’ll check the temp when I get the car back up and running.