4L60e won’t shift into 3rd after rebuild, commands 4th
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4L60e won’t shift into 3rd after rebuild, commands 4th Good afternoon, I got a 2003 Chevrolet S10, 4.3, 4L60e. Rebuilt transmission, still won’t go into 3rd. Scanner data shows that we are commanding 3rd and 4th and I believe it drops into 4th but I can’t tell, still has no power in 4th. Servo data shows that all servos are working properly and in their correct positions in relation to commanded gear.
Hoping I didn’t burn the clutches up within 5 minutes of driving. First time rebuilding a transmission and I unfortunately made the mistake of not checking everything I was supposed to check.
I believe that I missed the 3rd accumulator piston check valve, believing that I didn’t need to bother with it and that it’d be fine. It’s likely stuck, causing fluid to leak past. They say that any fluid leaking past that valve will disable 3rd gear, and that this little valve is one of the most common 4L60e failures.
Any good way to test this? Transmission is inside truck, and I’m not looking to drop it out again. Also wondering if it’s possible with a steady hand to R&R this check valve with the transmission still in the truck. It seems like a straight shot up the valve body with the special tool, I’d just have to keep track of all my check *****.
Scanner data shows that the TCM commands 3rd about 3 seconds before it actually attempts to shift, when it attempts to shift, it simply free-spools like i popped into neutral. Then when I let off, the TCM commands 4th, and RPMS stick around 2k. Foot on throttle action shows no results, just straight up neutralmaxxing 3rd and 4th.
Any advice? Or even recommendations or testing advice would be appreciated.
Hoping I didn’t burn the clutches up within 5 minutes of driving. First time rebuilding a transmission and I unfortunately made the mistake of not checking everything I was supposed to check.
I believe that I missed the 3rd accumulator piston check valve, believing that I didn’t need to bother with it and that it’d be fine. It’s likely stuck, causing fluid to leak past. They say that any fluid leaking past that valve will disable 3rd gear, and that this little valve is one of the most common 4L60e failures.
Any good way to test this? Transmission is inside truck, and I’m not looking to drop it out again. Also wondering if it’s possible with a steady hand to R&R this check valve with the transmission still in the truck. It seems like a straight shot up the valve body with the special tool, I’d just have to keep track of all my check *****.
Scanner data shows that the TCM commands 3rd about 3 seconds before it actually attempts to shift, when it attempts to shift, it simply free-spools like i popped into neutral. Then when I let off, the TCM commands 4th, and RPMS stick around 2k. Foot on throttle action shows no results, just straight up neutralmaxxing 3rd and 4th.
Any advice? Or even recommendations or testing advice would be appreciated.
TECH Junkie
Joined: May 2012
Posts: 3,046
Likes: 713
From: Poplarville, MS
You could unplug the big electrical connector on the passenger side of the trans. This will force 3rd gear at full line pressure.
Yes, you can place the check valve with the trans in the vehicle, but I doubt that the check valve is leaking so bad that you wouldn't have 3rd gear unless the trans had catastrophic frailer with lots of metal in the fluid. Most likely a mistake was made when assembling the input drum or there is excessive wear on the input shaft sealing ring groves or wear in the stator support where the input shaft sealing rings ride. Attached are some instructions on how to are test these components.
Yes, you can place the check valve with the trans in the vehicle, but I doubt that the check valve is leaking so bad that you wouldn't have 3rd gear unless the trans had catastrophic frailer with lots of metal in the fluid. Most likely a mistake was made when assembling the input drum or there is excessive wear on the input shaft sealing ring groves or wear in the stator support where the input shaft sealing rings ride. Attached are some instructions on how to are test these components.