What did your transmission temperature display say hot hot it was?

This has never happened on my '14 5.3L

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I wasn't on that page on my display so I don't know. Once it popped up it wouldn't let me change off of that screen. I limped it home and parked it. I'll see what it says in the morning. I feel like there's some sort of bad sensor because I've never had any transmission issues in the past and this just randomly happened tonight.

I could understand if I was beating on it but I wasn't. I was cruising at probably 70-72mph and it popped up.

 

Maybe the trans thermostat was stuck shut. Not likely but possible. Maybe consider a delete?

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UPDATE: Drove 17 miles, 30 minutes to work this morning. Trans Temp got up to 205. Check Engine light is still on, but "Transmission Hot Idle Engine" warning never reappeared. Transmission shifted fine, no slippage or hard shifts.

 

UPDATE: Drove 17 miles, 30 minutes to work this morning. Trans Temp got up to 205. Check Engine light is still on, but "Transmission Hot Idle Engine" warning never reappeared. Transmission shifted fine, no slippage or hard shifts.

I can't remember but I think your truck has no dipstick to check the fluid level. Could be wrong. I would be checking your trans fluid lines and thermostat for signs of a leak as a precaution. 205 deg seems a bit high...barely see that temp in 100 deg weather. Might be thinking of stopping by the dealer for a warranty check. The thermostat might be sticking closed.

 

Yeah I am betting the thermostat is sticking. It should only get up to 185F max for a short casual drive like that. Mine usually hangs out around 165F on morning drives to the office.

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There is a dipstick for the fluid, I checked it and it wasn't dirty or low. I had the transmission serviced at 50k miles, per the factory recommendation. Unfortunately my warranty is expired, so I am trying to avoid going to the dealer and paying the $135 diagnostic fee unless I know for sure something is really off.

The temp was in the mid 40s this morning so I thought it seemed a little high too, but wanted to check with everyone else.

 

Perhaps just have that whole transmission cooling line assembly replaced. I believe it comes with a new thermostat and it's only about $85 before labor.

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Thanks OilFracker. You think it's definitely worth a trip to the dealer then?

See youre in MT, I was stationed in Great Falls from 07-08. I miss it!

 

Thanks OilFracker. You think it's definitely worth a trip to the dealer then?

See youre in MT, I was stationed in Great Falls from 07-08. I miss it!

If your up to the task you could buy the new thermostat and install it yourself

its only 15lbs torque on the bolt and a couple clips to hold lines.

 

I'll check it out on YouTube, I'm sure I can do that myself.

 

Honestly I would not go to a dealer. The dealer quoted me about $350 to replace the cooler line assembly and thermostat housing. I went to a local transmission shop in Billings, MT and had it replaced for about $135 (parts and labor).

Yeah I love MT. Good place if you can stand the winters. Great Falls is a nice neighborhood too. Them Air Force boys hardly ever smile. They take nuke protection seriously [emoji38]!

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OilFracker, HAHAHA. I've done that job, during the MT winter. I wouldn't want the job again, but the Winter didnt bother me at all. I am from MI, so I am used to it

 

UPDATE 2: Just got off the phone with the dealership, my powertrain is still under warranty, so it's going in next Wednesday for diagnosis.

 

Congrats will be nice to hear what the fix is.

 

Indeed! I'm glad it is under warranty.

Here is some additional information that is good reading material. Click on this -----> https://r.tapatalk.com/shareLink?url=ht ... are_type=t

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Here's to hoping. I'll let everyone know in a week or so. They said they'd need my truck for 3 days to diagnose

 

Sorry to bombard you. If you get a new transmission thermostat they will likely be replacing the entire cooler line assembly that could be leaking too. Another issue may be passively getting fixed. It's a common/minor GM thing.

https://r.tapatalk.com/shareLink?url=ht ... are_type=t

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No need to apologize. I appreciate the info!

 

250°F triggers the warning.

 

Yesterday it was getting up to 210 just driving around locally.

 

210° is the high end of normal operating temp. Excessive shifting with cause temps to rise some. Low fluid will cause temps to rise. Too low fluid temps contribute to lower fuel economy. That's why Dexron VI is recommended, its a low viscosity fluid.

Here is some info I saved on atf temps that may be of interest;

In the February 2011 issue of Trailer Life magazine RV Clinic in response to a reader about the maximum transmission temperature allowed in a 2009 Chevy Silverado, the Tech Team had this response.

"General Motors' in-house towing team expert provided RV Clinic with this statement: The maximum allowable automatic transmission fluid temperature is dictated by the transmission oil itself. The oil begins to degrade significantly above 270 degrees Fahrenheit, so we design vehicles so that in all but the most extreme conditions, the fluid temperature in the transmission sump stays below 270 degrees F.

We allow for up to 285 degrees F in extreme conditions (i.e. towing a trailer with combination loaded at GCWR in Death Valley). But for customer usage anywhere else in the country, even at GCWR, transmission sump temperature should stay well below 270 degrees F. Above this point, certain internal components, such as seals, begin to disintegrate rather quickly. Although newer synthetic fluids can withstand higher temperatures we still recommend this (270F) as a maximum temperature. "

 

Thanks for the info Mike. I'm concerned because I never tow, the trans was serviced at 50k miles, fluid levels are fine, and this happened while cruising at 70mph. I'd understand if I had the trans under stress but this seems to have happened unprovoked. Worth the dealer looking at while it's under warranty still, IMO.

 

UPDATE: Dealership just called. The technician "drove my truck for multiple hours yesterday" and only got the transmission temp up to 212. I called them out on that, no way a technician drove my truck for multiple hours when he has other jobs to work on. They said the main issue with my truck is the high pressure fuel pump needs to be replaced ($1238), even though I've never had an issue with that before and my check engine light wasn't even on when I dropped the truck off. They offered to let me talk to the technician, which I said yes to. After 2 minutes on hold they notified me my technician was on a "test drive" and would call me later.

 

UPDATE: Talked to the dealer a second time. Turns out the technician "drove the truck for just over an hour", the trans got to 212F, and that's considered normal. I told them they are not authorized to fix my fuel pump, especially since I've never had an issue and they informed me I needed to pay a diagnostic fee for the fuel pump. I didn't ask them to fix anything in the fuel system, so why are they charging me a diag. fee for it? I darn well know they didn't "diagnose" anything, they pulled a code for the high pressure fuel pump and it told them it needed to be replaced.

Called GM Customer Service and opened a case. They are going to "try" to get my diagnostic fee back and they are elevating my case to a district manager to properly get my transmission diagnosed.