2016 Sierra RCSB Help

Anthonyvee90 · March 22

So drove my truck to work today after a month of not driving it.(have a commuter car). Truck was running fine all day. When I got home went for a food run with the wife, truck felt weird. Had it on drive but wouldn’t move unless I accelerated to 1.5k rpm. Drove it around the block it drove good above 1.2k rpm. Got home plug in the obd2 reader no codes. Waited about 2 hours tried it again and truck was even worse. Didn’t move on drive or reverse unless I accelerated and then it would kick into gear

is it time for a new transmission?

CamGTP · March 22

It's surely possible that the oil pump in the transmission gave out. Depending on mileage usually what happens is the torque converter slowly shreds itself and that takes out the pump on the transmission.

If you pulled the pan and it's full of clutch material and metal, the transmission is done for.

Anthonyvee90 · March 22

50 minutes ago, CamGTP said:

It's surely possible that the oil pump in the transmission gave out. Depending on mileage usually what happens is the torque converter slowly shreds itself and that takes out the pump on the transmission.

If you pulled the pan and it's full of clutch material and metal, the transmission is done for.

It’s a 95k

I will be dropping the pan today

newdude · March 22

Time for a rebuild if its losing drive. Pump isn't holding pressure and the torque converter likely took it out.

Make sure whatever route you go you install the updated lower temp GM transmission bypass valve.

Edited March 22 by newdude

mikeyk101 · March 22

Mine took a dump right around 95k last year. No warning and no symptoms. All of a sudden ust would go forwards or back up. New reman transmission was needed and I was good to go. 6L80 trans in my 2016.

MikeBMW · March 23

8 hours ago, newdude said:

Time for a rebuild if its losing drive. Pump isn't holding pressure and the torque converter likely took it out.

Make sure whatever route you go you install the updated lower temp GM transmission bypass valve.

Yep. I really want more people to know about this - I guess you could "flip the pill" I suppose?
Chevrolet TSB 21-NA-199.pdf

Anthonyvee90 · March 23

8 hours ago, mikeyk101 said:

Mine took a dump right around 95k last year. No warning and no symptoms. All of a sudden ust would go forwards or back up. New reman transmission was needed and I was good to go. 6L80 trans in my 2016.

I was thinking of dropping it myself and maybe going this route Transmission

newdude · March 24

22 hours ago, MikeBMW said:

Yep. I really want more people to know about this - I guess you could "flip the pill" I suppose?
Chevrolet TSB 21-NA-199.pdf

Depends IMO. 2016.5-2019 its worth doing the updated t-stat because it keeps some heat in the transmission, especially in the winter time. 16.5-19 V8 trucks, the transmission is cooled on its own, it does not go through the radiator first like the 14-16 and most all prior years to those. Winter they will barely get to 100F and can cause it to shift like its still ice cold fluid.

14-16 trucks can benefit from the pill flip or SureCool kit as the transmission goes through the radiator first then out to the aux cooler. These run warmer so the updated TBV would lower the opening point, sure, but they will still run hotter.

rlcole321 · March 26

Don't forget to flush the cooler lines and Trans Cooler (in the condenser)!

Dangelo · March 28

On 3/23/2025 at 8:12 PM, newdude said:

Depends IMO. 2016.5-2019 its worth doing the updated t-stat because it keeps some heat in the transmission, especially in the winter time. 16.5-19 V8 trucks, the transmission is cooled on its own, it does not go through the radiator first like the 14-16 and most all prior years to those. Winter they will barely get to 100F and can cause it to shift like its still ice cold fluid.

14-16 trucks can benefit from the pill flip or SureCool kit as the transmission goes through the radiator first then out to the aux cooler. These run warmer so the updated TBV would lower the opening point, sure, but they will still run hotter.

Is it beneficial for it to flow through the radiator like the 14-16’s. I have a 17 and I did the pill flip I used to be at 180-190 and now I’m at 160-170 is that still too hot? I believe my truck carry’s the aux cooler that’s in front of the radiator right ? Is that better then going to the radiator?

newdude · March 28

55 minutes ago, Dangelo said:

Is it beneficial for it to flow through the radiator like the 14-16’s. I have a 17 and I did the pill flip I used to be at 180-190 and now I’m at 160-170 is that still too hot? I believe my truck carry’s the aux cooler that’s in front of the radiator right ? Is that better then going to the radiator?

No as those run warmer with both the flip or the lower temp TBV.

2016.5-2019 run cooler. On the V8 1500s the condenser is a combi-cooler. Top 1/4 of it or so is transmission cooler. Its the aux on the 14-16, its the only cooler on 16.5-19.

Mine done with the SureCool delete (same idea as the pill flip) would struggle to get past 105F in the winter, and would get maybe to 140F in the summer not towing.

Under what scenarios are you seeing 160-170F after flipping? Towing? Empty? Hot outside? Cold outside?

Dangelo · March 29

I did the pill flip late last year towards the end of summer so I wasn’t able to get a good reading of the t-stat durning a hot normal day when the t-stat would read 170-190 w/o a trailer and 190-210 w/ trailer .But with it warming up, it was about a 65-70 degree day I was pulling a 10ft long by 4.ft wide flat bed tandem axel trailer that weighs up tow 3000lbs plus I also had about 2,200 plus lbs of cement bags on the trailer so about 5200lbs plus about 350lbs in cargo weight with tools in my bed and it was reading 170 while pulling, before when I would pull a trailer it would be at 190-210,This was durning summer days.

Even on cold winter days where I live can get to 15 degrees and before the flip I’d be at 135-150 w/o pulling in a winter day and now with the flip this winter I was at 120-140 w/o pulling. I haven’t gotten a good reading durning the summer since we’re approaching it but I’m curious to see what readings I get with out pulling on normal conditions

newdude · March 29

8 hours ago, Dangelo said:

I did the pill flip late last year towards the end of summer so I wasn’t able to get a good reading of the t-stat durning a hot normal day when the t-stat would read 170-190 w/o a trailer and 190-210 w/ trailer .But with it warming up, it was about a 65-70 degree day I was pulling a 10ft long by 4.ft wide flat bed tandem axel trailer that weighs up tow 3000lbs plus I also had about 2,200 plus lbs of cement bags on the trailer so about 5200lbs plus about 350lbs in cargo weight with tools in my bed and it was reading 170 while pulling, before when I would pull a trailer it would be at 190-210,This was durning summer days.

Even on cold winter days where I live can get to 15 degrees and before the flip I’d be at 135-150 w/o pulling in a winter day and now with the flip this winter I was at 120-140 w/o pulling. I haven’t gotten a good reading durning the summer since we’re approaching it but I’m curious to see what readings I get with out pulling on normal conditions

Sounds good then yea towing post flip and you are seeing 170F that is much better.

Dangelo · April 2

On 3/29/2025 at 6:13 PM, newdude said:

Sounds good then yea towing post flip and you are seeing 170F that is much better.

Hey question, ima tell you what my buddy would tell me when he wanted me to explain to him how I install whatever it was I was building or what have you but speak to me like a I’m child lol I understand homes not trucks or engines , but my question is, tuning an engine I’ve read enough but still don’t understand I have the 8spd 5.3 and i still haven’t found something like HPTuners that can work with the 8spd. Is there something out there for the 8spd that I can use ? And what exactly would my mechanic do ,once I get said tuner ?

newdude · April 2

36 minutes ago, Dangelo said:

Hey question, ima tell you what my buddy would tell me when he wanted me to explain to him how I install whatever it was I was building or what have you but speak to me like a I’m child lol I understand homes not trucks or engines , but my question is, tuning an engine I’ve read enough but still don’t understand I have the 8spd 5.3 and i still haven’t found something like HPTuners that can work with the 8spd. Is there something out there for the 8spd that I can use ? And what exactly would my mechanic do ,once I get said tuner ?

HP Tuners has 8 speed support. Requires unlocking your TCM through them or buying a new unlocked one from them - GM T87A TCM Services – HP Tuners

I wouldn't just have a "mechanic" play with HP Tuners either. Just find a good, reputable tuning shop and have them tune the engine and transmission with HP, which the shop would likely have all the HP software and hardware already.