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- Dec 4, 2023
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Particularly at wot. Pulled it back out, clearances are still in spec. Before I pulled it I put another 3rd accumulator capsule in it and swapped the valve body with no difference.
4l60e delayed 2-3 shift after rebuild.
- Thread starter tolericodominic
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- Dec 4, 2023
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I recently did a stock rebuild on a 4l60e that came in with a failed band and 3-4 clutches. I tested all the usual suspects, and replaced the 3rd accumulator check ball. With everything installed to spec I installed the unit to find no 2-3 shift at wot, and delayed 2-3 shift at part throttle. After pulling it and tearing it down again I found that the servo pin bore in the case will only hold 7 inches of vacuum when traveling in it's functional range. I'm thinking that when the 2-3 shift is commanded, the oil attempting to release the band is crossing into the 4th apply piston and inhibiting the release. Has anyone else found this particular scenario with case wear. I'd like to confirm it's the issue before I search for a case and put it all back together.
Before I pulled the transmission I did change the solenoids thinking that possibly it was blocked. I also put another 3rd accumulator capsule in just in case I got a bad one the first time. Driving it on the lift shifting manually it has a positive 1-2 shift, and then after about a 3 second delay from moving the selector to 3rd it shifts. Once in 3rd on a drive it doesn't slip. Wide open throttle it won't make the shift. It's the worst vacuum level of a pin bore I've tested so far. But I've never heard of that inhibiting a 2-3 shift.
The AFL holes are .093 in the new plate. The original plate they are about .050
Before I pulled the transmission I did change the solenoids thinking that possibly it was blocked. I also put another 3rd accumulator capsule in just in case I got a bad one the first time. Driving it on the lift shifting manually it has a positive 1-2 shift, and then after about a 3 second delay from moving the selector to 3rd it shifts. Once in 3rd on a drive it doesn't slip. Wide open throttle it won't make the shift. It's the worst vacuum level of a pin bore I've tested so far. But I've never heard of that inhibiting a 2-3 shift.
The AFL holes are .093 in the new plate. The original plate they are about .050
A Sonnax Band Apply Pin has the early model ('82-'86) 700R4 PTFE Seals where the pin rides in the case bore.
This is why I build all my sub 400 horsepower 4L60E's the same exact way & control shift firmness with feed orifices sizing & accumulator valve spring weight.
*New "093" Vette 2nd Servo as it provides a cleaner 2-3 shift than a smaller "553", And servo pistons wear out where the pin rides.
*Sonnax Apply Pin to seal the Pin Bore in the Case & 2nd Servo Piston, Also allows me to tighten the Band Clearance.
*I reseat the checkball in the 3rd Accumulator Capsule with a flat nosed punch using a couple raps with a small ball peen, Hardly ever need to swap the Capsule.
*Notch the 2nd servo cushion spring retainer along with adding 2 extra cushion springs via TransGo SK-4L60E shift kit, Cleans up the 3-2 Downshift & helps calm the 1-2 Thump.
*New Boost Valve, Prefer a Sonnax O-Ringed .490"
*Blueprint the pump with the correct thickness AC-Delco Rotor & Slide, New Slide Pin, TransGo Hi-Rev Pump Rings & Primer Spring.
*.086" Band Release Orifice in the plate, TransGo calls for .093" which is to large.
*The White TransGo helper spring inside the original AFL Valve Spring shores up AFL Pressure.
*7 Borg Warner .080" 3-4 Frictions, Set at .025" after leveling the 3-4 Apply Plate, New Sonnax Booster Springs, Of coarse leak check the Input Drum.
*New Input Shaft PTFE Seals....Sized correctly.
*New Sonnax Bore Plugs in the Valve Body.
I've had 1 come back in the last 5 years because of a Torque Converter issue, Must be over 100 units & I give a 3 year unlimited mileage warranty.
The first thing to do on a problem unit before pulling it.....Check the line pressure!! I like to see 210-230 PSI on my units at WOT (Zero Amps Applied to the EPC), You'll see less with a stock PR Spring.....180 PSI is the minimum I would accept/expect on a stock unit.
The 3rd apply circuit is quite large & takes time from when the Solenoid is turned off for the 3-4's to physically apply, I run across this on "Tuned" Vehicles often.....Got to tune the MPH apply lower than where you want the 2-3 shift to happen.
This is why I build all my sub 400 horsepower 4L60E's the same exact way & control shift firmness with feed orifices sizing & accumulator valve spring weight.
*New "093" Vette 2nd Servo as it provides a cleaner 2-3 shift than a smaller "553", And servo pistons wear out where the pin rides.
*Sonnax Apply Pin to seal the Pin Bore in the Case & 2nd Servo Piston, Also allows me to tighten the Band Clearance.
*I reseat the checkball in the 3rd Accumulator Capsule with a flat nosed punch using a couple raps with a small ball peen, Hardly ever need to swap the Capsule.
*Notch the 2nd servo cushion spring retainer along with adding 2 extra cushion springs via TransGo SK-4L60E shift kit, Cleans up the 3-2 Downshift & helps calm the 1-2 Thump.
*New Boost Valve, Prefer a Sonnax O-Ringed .490"
*Blueprint the pump with the correct thickness AC-Delco Rotor & Slide, New Slide Pin, TransGo Hi-Rev Pump Rings & Primer Spring.
*.086" Band Release Orifice in the plate, TransGo calls for .093" which is to large.
*The White TransGo helper spring inside the original AFL Valve Spring shores up AFL Pressure.
*7 Borg Warner .080" 3-4 Frictions, Set at .025" after leveling the 3-4 Apply Plate, New Sonnax Booster Springs, Of coarse leak check the Input Drum.
*New Input Shaft PTFE Seals....Sized correctly.
*New Sonnax Bore Plugs in the Valve Body.
I've had 1 come back in the last 5 years because of a Torque Converter issue, Must be over 100 units & I give a 3 year unlimited mileage warranty.
The first thing to do on a problem unit before pulling it.....Check the line pressure!! I like to see 210-230 PSI on my units at WOT (Zero Amps Applied to the EPC), You'll see less with a stock PR Spring.....180 PSI is the minimum I would accept/expect on a stock unit.
The 3rd apply circuit is quite large & takes time from when the Solenoid is turned off for the 3-4's to physically apply, I run across this on "Tuned" Vehicles often.....Got to tune the MPH apply lower than where you want the 2-3 shift to happen.
- Joined
- Dec 4, 2023
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- 8
clinebarger do you think the worn pin bore could cause the no 2-3 at wot?
Any leak in the 3rd clutch circuit can cause odd Band/3-4 Clutch Timing issues.
What vehicle is this??
What vehicle is this??
- Joined
- Dec 4, 2023
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- 8
2000 Camaro Z28
And it's stock?
Let's say this happened to me.....
*Pressure Gauge! Low line pressure kills frictions & it's impossible to diagnose shift concerns with low line pressure.
*Verify the PCM is commanding both Solenoids off "Cleanly", Best to use a Scope....But can be done with Amperage via a DVOM
Let's say this happened to me.....
*Pressure Gauge! Low line pressure kills frictions & it's impossible to diagnose shift concerns with low line pressure.
*Verify the PCM is commanding both Solenoids off "Cleanly", Best to use a Scope....But can be done with Amperage via a DVOM
- Joined
- Dec 4, 2023
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I did check the line pressure and it was in spec. Yes it's a stock ls1. The pcm would command the shift but it took 3 seconds after the command at light throttle to actually shift. I just finished rebuilding a good core to put in the car so I will find out if the pcm drivers are the issue. If the new unit shifts fine I will have to find out what the cause is. I had one other trans do this and I changed the case to fix it. I can't see that happening twice but I guess it's possible.
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- Dec 4, 2023
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Well you nailed it. PCM was hanging the solenoid release. I actually changed the trans again and had the exact same symptom before I found it. The logic was commanding the shift, but the quad driver wasn't shutting off the solenoid cleanly.!!!!!
What caused the "quad driver" to not shut off cleanly?
2000 is not old for electronics. Are there any electolytic capacitors inside that went bad and spilled onto the ciruits?
How do you repair the "quad driver".
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- Dec 4, 2023
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You don't repair it, you change the pcm typically. I'm sure it could be repaired if someone wanted to take the time. But it's not worth it imo
So did the old transmission have an internal electrical issue that blew the driver in the PCM?
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- Dec 4, 2023
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