Updated 6l80E thermostat question

[Tnsilverado]

I have a 2018 Silverado 5.3 with the 6 speed. The truck has 5,000 miles on it. I actually bought it a month ago. I seen there was a TSB on the TBV so I told them to go ahead and put the updated thermostat in the truck. Temps were running 185-195 just driving. I haven’t towed with it yet. After getting the truck back temps are still 180-185. It was much colder than what it was when I first got the truck. Low 40s. Did a highway run 60 miles temp was 176 as soon as I got back to town it shot up to the mid 180s. Everything I’m reading says it should be around 160. Anyone else have this happen? Also, from my understanding the new valve is supposed to be marked with a 70 since it now opens at 70c. I got under the truck and this one does not have that. The part number they have on the work order is 85585333. I know it’s superseded a few times but does anyone know if this new number still has that 70 stamped on it? I’m just trying to see if I paid for something that the dealer didn’t actually change. Thanks

[rav3]

You need to do the thermostat bypass or "pill flip" to help make your transmission last longer.

 

 

Edited January 13, 2024 by rav3

[Tnsilverado]

7 minutes ago, rav3 said:

You need to do the thermostat bypass or "pill flip" to help make your transmission last longer.

 

 

well I was hoping this would do the same thing being that it’s supposed to open about 40 degrees cooler than the original one. I’d consider doing something else once my warranty is up. I still have 5 years on my power train. I’m assuming that would void it. Correct me if I’m wrong. 

[rav3]

I don't think it would.......but do what you want to do or feel comfortable with. I did the pill flip on my '17 6L80 within the 1st month I bought it. And I believe your drive train warranty is 6 years or 100k miles (from in service date) so your warranty may be ending this year.

[Tnsilverado]

7 minutes ago, rav3 said:

I don't think it would.......but do what you want to do or feel comfortable with. I did the pill flip on my '17 6L80 within the 1st month I bought it. And I believe your drive train warranty is 6 years or 100k miles (from in service date) so your warranty may be ending this year.

I may just do the pill flip. I got lucky on the warranty. I got 10 years or 100k. I just don’t want to burn this thing up. Why GM thought this was a good idea is beyond me

[Tnsilverado]

9 minutes ago, rav3 said:

I don't think it would.......but do what you want to do or feel comfortable with. I did the pill flip on my '17 6L80 within the 1st month I bought it. And I believe your drive train warranty is 6 years or 100k miles (from in service date) so your warranty may be ending this year.

What temps do you see in the winter months, if it even gets cold in your area. That’s the only thing that concerns me with pill flip 

[mikeyk101]

Yes, it is listed as the most current part and it still should have the "70" stamped into the base. It is a 154⁰ thermostat. Based on the temps you are seeing, it doesn't sound right. Mine will usually run in the upper 140's to 150's until I get in stop and go traffic where it will sometimes rise into the upper 160's or 170's. It will drop back down once rolling steady again. If yours is not stamped, I would suggest having a discussion with them.

 

As far as winter driving, with new thermostat, it will still need to warm up just as the old one did, it just starts circulating the trans fluid sooner. If you flip the pill, it will take longer for it to warm up as the fluid will be circulating from the beginning. I would think it will take a much longer time to warm up. These trannies don't seem to like being cold and shift a bit hard when cold.

Edited January 13, 2024 by mikeyk101

[newdude]

10 hours ago, Tnsilverado said:

I have a 2018 Silverado 5.3 with the 6 speed. The truck has 5,000 miles on it. I actually bought it a month ago. I seen there was a TSB on the TBV so I told them to go ahead and put the updated thermostat in the truck. Temps were running 185-195 just driving. I haven’t towed with it yet. After getting the truck back temps are still 180-185. It was much colder than what it was when I first got the truck. Low 40s. Did a highway run 60 miles temp was 176 as soon as I got back to town it shot up to the mid 180s. Everything I’m reading says it should be around 160. Anyone else have this happen? Also, from my understanding the new valve is supposed to be marked with a 70 since it now opens at 70c. I got under the truck and this one does not have that. The part number they have on the work order is 85585333. I know it’s superseded a few times but does anyone know if this new number still has that 70 stamped on it? I’m just trying to see if I paid for something that the dealer didn’t actually change. Thanks

 

 

So the new one starts to open at 138-145F/59-63C and is full open at 158F/70C.  When I did mine on a hot summer day it would stabilize 160-170F or so.  This was mostly highway driving, and then 35-45mph getting home with low traffic.  

 

There are multiple scenarios that can elevate transmission temperature.  Lots of stop and go, slow speed around town driving, restricted transmission cooler, etc.  Seeing you only have 5,000mi on the truck, a restriction seems unlikely and it seems more environmental cause. 

 

A new defective TBV you'd see that thing overheat and not stabilize temperatures.  

[Tnsilverado]

7 hours ago, mikeyk101 said:

Yes, it is listed as the most current part and it still should have the "70" stamped into the base. It is a 154⁰ thermostat. Based on the temps you are seeing, it doesn't sound right. Mine will usually run in the upper 140's to 150's until I get in stop and go traffic where it will sometimes rise into the upper 160's or 170's. It will drop back down once rolling steady again. If yours is not stamped, I would suggest having a discussion with them.

 

As far as winter driving, with new thermostat, it will still need to warm up just as the old one did, it just starts circulating the trans fluid sooner. If you flip the pill, it will take longer for it to warm up as the fluid will be circulating from the beginning. I would think it will take a much longer time to warm up. These trannies don't seem to like being cold and shift a bit hard when cold.

that’s the info I was looking for. It seems like they didn’t replace it after charging me $300 to change it. The temps are exactly the same and the “new” valve is not stamped with 70. Guess I’ll be making a trip over there Monday…

[rlcole321]

I think your right, they didn't change it or installed the wrong one, maybe there on back order (I had mine done a couple of years ago and had to wait because it was on back order), some info, your trans cooler is part of the AC condenser and not in the radiator (unless you have a heavy duty tow packages)

[Tnsilverado]

Here’s an update for anyone wanting to know. I called around to a few dealers that had the part in stock, they all said that the new part number 85585333 no longer is stamped with the 70 on the bottom. They assume it’s since the original is no longer being produced there wasn’t a reason to stamp it? I even went to another local dealer and seen it myself. No stamp. I’m dropping the truck off in the morning. I talked to my service advisor and he said something was off. He had the update on his truck and his temps are in the 160 range and 170s while towing. I’m way over that just driving. We’ll see what they come up with. 

[Tnsilverado]

Here’s an update for anybody interested. Got the truck back this evening. They said the first tbv they installed was faulty and was causing an obstruction so that led to the high temps. I don’t really buy that because you would imagine if flow to the cooler was obstructed the transmission would get super hot, not just the temp it got originally. Who knows for sure. I still think they just didn’t swap it. Anyway, the trans temps are much better now. Went on a long drive in the city and back roads and temps leveled at at 140-145. I took the same drive this morning as a control and temps were 187. So the new valve definitely works at reducing trans temps. I also checked under the truck and the new valve is not stamped with the 70 as the previous ones were. So just know if you go to purchase one don’t be surprised if it doesn’t have the stamp. 

[dzsmith]

Sounds like you got scammed dude . Take it back, and show them that it doesn’t have a 70 stamped on it. I literally replaced mine in the last calendar year and it has a 70 stamped on it….. now , as far as the temperature , if I drive all day long or at least over an hour in hot weather or under heavy load I have still seen fairly high temps , but I would say average at once heated up is 160s and 70s verses originally in the 180s and 90s all the time but never quite hot enough for it to open . With it opening at 158 on the new i at least know it’s going through the rad where as before on a 10 hour road trip at 192 pegged it was just sitting there cooking.