Hard / Delayed shift issues

[Wdrookie]

About 2 weeks ago I did routine maintenance to my 2002 Duramax (100% original stock, no upgrades or controllers ever) including drain & fill transmission fluid and changed spin-on filter. About a day and a half later I started getting delayed & hard upshifts. I drove for another day until the Service engine soon light came on. When I checked the code it was P0700 & P0757- Shift Solenoid B Stuck On. I took it to the transmission shop and they also pulled a code P0777 Pres Ctrl Solenoid B Stuck On. They proceeded to pull the pan and said there were no signs of any debris in the pan. They changed solenoid B and the other shift solenoids. All were changed except for Solenoid A. They said they checked the internal wiring for chaffing and or burnt spots and did not find any. That did not change the delayed & hard upshifts. They tried to re-flash the TCM but said it would not take. They also told me they tapped on the TCM and the shift pattern changed. They reset the TAPs. This relieved the hard upshift but now it had really hard down shift on 4-3 & 3-2 shifts. I have driven the truck for about a week now. Current condition is Delayed hard shift from park or drive into reverse. In Drive, I get a nice smooth shift into 1st and a smooth up shift from 1-2. The 2-3 shift is delayed and hard almost like it goes to neutral for a second. The 3-4 shift is faster and not as hard but I would not call it correct. The 4-5 shift is delayed and hard almost like it goes to neutral for a second. There are currently no codes showing.
This morning I tried swapping the TCM out for another USED TCM and the shifting problems remain. The transmission shop wants to put in a new or remanufactured TCM to see if that will fix it. I need guidance on how to proceed. It doesn’t make since to me that a new TCM would fix this issue since the used one didn’t change anything. Any help you can give me would be appreciated.

Robin

 

[nsolimini]

Now I am no expert by any means, but I would suggest dropping the valve body and ensuring the valves can move freely. Also check to make sure nothing is in the channels of the valve body, but someone with more knowledge will check in here and give you their take.

 

[Awenta]

Go somewhere where they know what they're doing

Sent from my SM-N910V using Tapatalk

 

[DAVe3283]

Also be warned, that if you are above stock power levels (or just very unlucky) you can break hard parts while this is happening. My transmission started having an intermittent hard or delayed 3-4 shift, delayed shifting into drive, and hard shifting into reverse (but only every other time). It wasn't that bad (or so I thought), and no check engine light, so I just drove it. Few thousand miles later, and I destroyed the C2 hub and P2 planet. Turns out a trim spring had broken, causing poor control of internal pressures.

So yes, get to a shop that knows what they are doing. Paying hundreds in labor more for a good shop to do a "simple" fix like a new trim spring ($2) is better than needing new hard parts (thousands) because a poor shop couldn't find the problem.

 

[TheBac]

You are 14 miles away from Josh @ TopNotchGarage in Van, TX. See his information in the vendor section. Dont take it anywhere else.

 

[c20elephant]

About 2 weeks ago I did routine maintenance to my 2002 Duramax (100% original stock, no upgrades or controllers ever) including drain & fill transmission fluid and changed spin-on filter. About a day and a half later I started getting delayed & hard upshifts. I drove for another day until the Service engine soon light came on. When I checked the code it was P0700 & P0757- Shift Solenoid B Stuck On.


I took it to the transmission shop and they also pulled a code P0777 Pres Ctrl Solenoid B Stuck On. They proceeded to pull the pan and said there were no signs of any debris in the pan. They changed solenoid B and the other shift solenoids. All were changed except for Solenoid A.


They said they checked the internal wiring for chaffing and or burnt spots and did not find any. That did not change the delayed & hard upshifts. They tried to re-flash the TCM but said it would not take.


They also told me they tapped on the TCM and the shift pattern changed. They reset the TAPs. This relieved the hard upshift but now it had really hard down shift on 4-3 & 3-2 shifts. I have driven the truck for about a week now.

Current condition is Delayed hard shift from park or drive into reverse. In Drive, I get a nice smooth shift into 1st and a smooth up shift from 1-2. The 2-3 shift is delayed and hard almost like it goes to neutral for a second.


The 3-4 shift is faster and not as hard but I would not call it correct. The 4-5 shift is delayed and hard almost like it goes to neutral for a second. There are currently no codes showing.


This morning I tried swapping the TCM out for another USED TCM and the shifting problems remain. The transmission shop wants to put in a new or remanufactured TCM to see if that will fix it. I need guidance on how to proceed.

It doesn’t make since to me that a new TCM would fix this issue since the used one didn’t change anything. Any help you can give me would be appreciated.

Robin

"More better.."

Ditto on TheBac suggestion, I was fortunate on my transmission when it went haywire, I found the connector at the passenger rear of the transmission not seated completely after 3 hours of looking for chaffed wires.

 

[Wdrookie]

Thanks for the suggestions. I'm going to see Josh

 

[Wdrookie]

Big shout out and Thank You to Mike L for taking the time to talk to me about my transmission issues and for the recommendation of Josh H at Top Notch Garage.

Josh/Top Notch Garage, thank you for listening to me about the transmission issues and for giving me options for repair that met my needs. I really appreciate you calling back after the repair just to check and see how everything was running. 1st Class.


Merry Christmas to all.

Robin

 

[chevyburnout1]

Great to hear! !

 

[Mike L.]

Big shout out and Thank You to Mike L for taking the time to talk to me about my transmission issues and for the recommendation of Josh H at Top Notch Garage.

Josh/Top Notch Garage, thank you for listening to me about the transmission issues and for giving me options for repair that met my needs. I really appreciate you calling back after the repair just to check and see how everything was running. 1st Class.


Merry Christmas to all.

Robin

What was wrong with it?

 

[Wdrookie]

Josh pulled the transmission and rebuilt the C3 clutch assembly. He said the C3 piston seal were hard and not sealing properly and allowing the fluid to go between the piston and bore. All other clutches were in good shape. I also opted for the Mike L spring upgrade and a Trans-go shift kit. While it was out we also installed a new torque converter.

 

[TeaBagger2006]

:thumb: