Hi,
132K on my 2015 LT. Bought at 93K miles from a dealer. They had just services the tranny. Was fine for about 30K miles. Sometimes some mild rpm flair at 2-3 shift depending on throttle position. Then 6 months ago during very timid driving and out of the blue 3-2 & 2-1 downshifts were hard, almost slams. Next day it was fine. So for the past 6 months on occasion I'd have a harder than normal 3-2 and or 2-1 down shifts. But nothing like the previous "slams". Then a week ago after pulling into traffic under moderate to heavy acceleration, I let off the gas, then tried to throttle back up and it was like my foot was on the brake. Engine was laboring but I was slowing down, like a power brake if your familiar with the term. It got so bad I turned on the 4-way flashers getting ready to get over to the shoulder. But after working the throttle it "freed up"(4-6 seconds?) and I continued on my way. But now the slam down shifts were back but only at 2-1. Next day car was fine. Called the transmission shop and made an appointment for the following (this) week. I continued to drive the car and other than an occasional noticeable hard-ish 2-1 down shift it was fine for several days. Then last night without thinking I had another instance of a few seconds of significant acceleration, cruised at 35mph for about a half mile and as I came to a stop sign, harsh deceleration and the same "binding" issue (laboring issue but the car didn't want to move. Stuck in two gears at the same time when downshifting?). Shifted between N (car freed up & coasted fine) and D (bogged back down) several times and eventually it freed up and again was on my way but the harsh downshifts were back. Drove the car today and other than hard 2-1 downshifts its fine. No abnormal noises, no codes pending or otherwise. I take it to the shop tomorrow. But has anyone else experienced this and if so, what was the culprit? I've read about valve body issues. Also wave plate issues but most of that was Gen 1 and that results in a "snowballing grenade" that I can't see being a come & go thing. Also the fact no codes have been set is perplexing. I've been watching some 6T70 rebuild videos and have learned about a "fluid dam" in the 3-5-R area? Wondering if there's a leak allowing fluid build up keeping a piston from releasing a clutch that might go undetected electronically? Anyway, if you care to offer advice or experience I'd appreciate your time. Thank you. And I will post the fix once it's known. BTW - local top dog tranny shop says $2K-$6K (updated valve body to complete overhaul). Thanks for reading & take care
132K on my 2015 LT. Bought at 93K miles from a dealer. They had just services the tranny. Was fine for about 30K miles. Sometimes some mild rpm flair at 2-3 shift depending on throttle position. Then 6 months ago during very timid driving and out of the blue 3-2 & 2-1 downshifts were hard, almost slams. Next day it was fine. So for the past 6 months on occasion I'd have a harder than normal 3-2 and or 2-1 down shifts. But nothing like the previous "slams". Then a week ago after pulling into traffic under moderate to heavy acceleration, I let off the gas, then tried to throttle back up and it was like my foot was on the brake. Engine was laboring but I was slowing down, like a power brake if your familiar with the term. It got so bad I turned on the 4-way flashers getting ready to get over to the shoulder. But after working the throttle it "freed up"(4-6 seconds?) and I continued on my way. But now the slam down shifts were back but only at 2-1. Next day car was fine. Called the transmission shop and made an appointment for the following (this) week. I continued to drive the car and other than an occasional noticeable hard-ish 2-1 down shift it was fine for several days. Then last night without thinking I had another instance of a few seconds of significant acceleration, cruised at 35mph for about a half mile and as I came to a stop sign, harsh deceleration and the same "binding" issue (laboring issue but the car didn't want to move. Stuck in two gears at the same time when downshifting?). Shifted between N (car freed up & coasted fine) and D (bogged back down) several times and eventually it freed up and again was on my way but the harsh downshifts were back. Drove the car today and other than hard 2-1 downshifts its fine. No abnormal noises, no codes pending or otherwise. I take it to the shop tomorrow. But has anyone else experienced this and if so, what was the culprit? I've read about valve body issues. Also wave plate issues but most of that was Gen 1 and that results in a "snowballing grenade" that I can't see being a come & go thing. Also the fact no codes have been set is perplexing. I've been watching some 6T70 rebuild videos and have learned about a "fluid dam" in the 3-5-R area? Wondering if there's a leak allowing fluid build up keeping a piston from releasing a clutch that might go undetected electronically? Anyway, if you care to offer advice or experience I'd appreciate your time. Thank you. And I will post the fix once it's known. BTW - local top dog tranny shop says $2K-$6K (updated valve body to complete overhaul). Thanks for reading & take care
