RPM Fluctuation

[RobbyD]

Sounds good, man. Let us know if you have any more questions or run into any problems.

Sorry for the long delay. I just got my Hoe back from the Trans shop today. My guy was super backed up and had me on hold for a couple of weeks. He wound up replacing the TCC Valve with the Sonnax unit. Not sure if one of y'all had mentioned that specific unit, but that's what was put in. I've yet to test her out. Just wanted to get you guys the update I promised. I'll do another update in about a week to let everyone know how she's running and if that solved my issue.

He saw no other issues while he was in there and road tested it himself, so I'm hopeful. Thanks again for everyone's help and insight along the way.

 

[RobbyD]

Update for everyone. It seems that the issue has only been suppressed with this most recent fix. While I will still get some RPM fluctuation, it's not a repeatable as before. I'm thinking it might be a torque converter at this point. Like I said, It's hard for me to "try" and make the RPMs jump like they once did, but it seems at random times it'll decide to do it. The sweet spot before seemed to be between 45-55 mph in overdrive under slight load. I have not had the chance to call my mechanic to update him as I've been so busy this last month.

I'll try and get the autel again to see what kind of TCC slip I'm getting. If anyone has any other diagnostics for me to run let me know. Thanks gents.

 

[MWD_CTSV]

Update for everyone. It seems that the issue has only been suppressed with this most recent fix. While I will still get some RPM fluctuation, it's not a repeatable as before. I'm thinking it might be a torque converter at this point. Like I said, It's hard for me to "try" and make the RPMs jump like they once did, but it seems at random times it'll decide to do it. The sweet spot before seemed to be between 45-55 mph in overdrive under slight load. I have not had the chance to call my mechanic to update him as I've been so busy this last month.

I'll try and get the autel again to see what kind of TCC slip I'm getting. If anyone has any other diagnostics for me to run let me know. Thanks gents.

That is classic TCC slip. The Sonnax TCC valve will help, but I think the bigger part of the problem is the actual software logic around the way the pressure on the TCC is estimated and applied. Without going to a different converter, I think the best pseudo-fix is to increase the offset pressure setting in the tune and the pressure gain ratio.

 

[RobbyD]

That is classic TCC slip. The Sonnax TCC valve will help, but I think the bigger part of the problem is the actual software logic around the way the pressure on the TCC is estimated and applied. Without going to a different converter, I think the best pseudo-fix is to increase the offset pressure setting in the tune and the pressure gain ratio.

I forgot to mention, on stock tune, it was worse than when I put my AFM delete and 93 octane tune on. It was severely reduced with the latter as mentioned in my last post. I'd have to reach out to 5-star tuning for them to adjust that tune for me, but I was hoping to go with Blackbear this time around so I might not even bother reaching out to them. I'm going to be moving to Florida (from New Jersey) in a couple of months here though and don't have the extra funds to spend freely on the old girl right now. I'll be towing an 8x12 trailer down with me. To my knowledge, while I'm in tow/haul mode I shouldn't have any issues.

Please advise if I should be worried about anything in that regard as I was just prepared to push it.

 

[MWD_CTSV]

I forgot to mention, on stock tune, it was worse than when I put my AFM delete and 93 octane tune on. It was severely reduced with the latter as mentioned in my last post. I'd have to reach out to 5-star tuning for them to adjust that tune for me, but I was hoping to go with Blackbear this time around so I might not even bother reaching out to them. I'm going to be moving to Florida (from New Jersey) in a couple of months here though and don't have the extra funds to spend freely on the old girl right now. I'll be towing an 8x12 trailer down with me. To my knowledge, while I'm in tow/haul mode I shouldn't have any issues.

Please advise if I should be worried about anything in that regard as I was just prepared to push it.

If it runs better with the AFM delete tune, then definitely use that one. I possibly has additional tuning for the trans.

 

[NickTransmissions]

Update for everyone. It seems that the issue has only been suppressed with this most recent fix. While I will still get some RPM fluctuation, it's not a repeatable as before. I'm thinking it might be a torque converter at this point. Like I said, It's hard for me to "try" and make the RPMs jump like they once did, but it seems at random times it'll decide to do it. The sweet spot before seemed to be between 45-55 mph in overdrive under slight load. I have not had the chance to call my mechanic to update him as I've been so busy this last month.

I'll try and get the autel again to see what kind of TCC slip I'm getting. If anyone has any other diagnostics for me to run let me know. Thanks gents.

He should have fully vac tested that valve body, all valve trains. Also what TCC valve did he replace? There's three of them in that trans though only the TCC regulator valve is accessible without pulling the trans and removing the pump so Im guessing its that one. The Sonnax valve seals that bore completely so that helps but the damage to the converter clutch has already been done.

I say its time to replace the torque converter and prob overhaul the transmission.