Crazy transmissionn temps

[rdezs]

Many threads. Just search the forum for AFM delete....

 

[Geotrash]

I just talked to a transmission shop and got some advice/bad news. I just realized that I have never listed the mileage for this vehicle - it's at 239k. Anyway, after going through the story with the shop owner he thought it sounded like a torque convertor failing. He said that if it drives and shifts like normal but the TC never locks up then it gets real hot real fast and that 230k miles is a long life for this transmission. What do you think? I know the motor has been acting tired but actually did pretty well in with a compression check last winter so I didn't think too much more about a rebuild. If I need a new trans I might as well get a new motor as well. The rest of the vehicle is in pretty good shape and the whole family does better on trips in this than they do with my F350.
I thought I read somewhere that a 6.2L will just drop right in with no other changes. Is that true? Maybe I could find a wrecked one somewhere and do a swap? I know we cannot afford a rebuilt trans right now much less a new trans AND motor or, heaven forbid a new vehicle.

Just a thought...has the transmission ever been replaced or rebuilt previously? If so, we've found that some shops take a shortcut and simply bypass either the oil-to-water cooler in the end tank of the radiator, or the external oil-to-air cooler in front of it, or both. They do this to avoid having debris contamination from the preceding transmission failure cause any more problems.

To check for this, check the routing of your transmission cooler lines. Fluid should flow from the transmission into the bottom of the radiator end tank on the pax side, out the top of it to the external cooler in front of the radiator, and back to the transmission.

 

[wyomingcowboy]

Thanks. I'm pretty sure this is all original factory equipment. The hose routing is a it should be. The story of the non-locking up TC is so far the best fit scenario. Trans still shifts and runs like it should but the temps just keep on climbing until I shut it down

 

[j91z28d1]

could the temp sensor be bad?

I think I've heard it's sump oil temp? could you use a temp gun on the pan or a line to the cooler to see if it's really 250 plus deg

 

[wyomingcowboy]

That's a good idea. I do have a temp gun. I'll try that this afternoon

 

[wyomingcowboy]

@NickTransmissions Does this sound like the likely culprit - that the TC has crapped out and will not lock up thus causing higher temps? There are no restrictions in flow and the fluid level is fine, and the trans itself shifts and behaves as it should. It's just that the temps climb and climb and never really come down. Or possibly there is a malfunctioning temp sensor, but I would suspect much more erratic fluctuation if it was just a sensor. (I'm going to try one more time today and shoot some temps with a temp gun but I have found a used transmission with 101k miles for $1800 and an 8 hour round trip drive.)

 

[wyomingcowboy]

I've got the old trans out and the used one ready to go in. Hopefully I'll have it done by early afternoon. Will I need to have it programmed at the dealer or by someone with the GM software?

 

[wyomingcowboy]

@NickTransmissions Does this sound like the likely culprit - that the TC has crapped out and will not lock up thus causing higher temps? There are no restrictions in flow and the fluid level is fine, and the trans itself shifts and behaves as it should. It's just that the temps climb and climb and never really come down. Or possibly there is a malfunctioning temp sensor, but I would suspect much more erratic fluctuation if it was just a sensor. (I'm going to try one more time today and shoot some temps with a temp gun but I have found a used transmission with 101k miles for $1800 and an 8 hour round trip drive.)

I got the old trans out last night. The TC looks like it has been HOT! It is very dark in color and the fluid smells horrible. This is new fluid that I just flushed out and replaced less than 100 miles ago. Fingers crossed that this used one holds up. (I know that i should have gone with a rebuilt and new TC, etc but I am very strapped for cash..that's why I'm doing it myself)