4L60E possible EPC solenoid problem
Thread Starter
Teching In
Joined: Dec 2009
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4L60E possible EPC solenoid problem Ok, so my ride is a truck and not a car so hopefully that's cool with you guys.
I've got a 2001 4.8 and 4L60E swap in a 97 S10. Custom harness so it's 100% functional still being run by the 2001 silverado PCM.
Here's my issue, I had the trans totally rebuilt with a few upgrades like corvette servo, beast sunshell, better clutches, ect... When I picked the trans up, the guy said that he turned something up to make it shift harder. I don't remember exactly what he said though.
Anyway, I've got about 4k miles on the trans and it's acting REALLY weird. It used to hammer second and third and felt super crisp and responsive. Lately, it feels like it won't go into overdrive in the mornings when the trans is cold, second is no where even CLOSE to a firm shift accept for 1 out of maybe 10 1->2 shifts where it actually hits hard like it's supposed to. It feels like it lags on shifting gears sometimes.
It's really unpredictable. The weirdness varies each time it shifts. From what I've read, it sounds like it could possibly be an EPC solenoid issue. I also read that the EPC solenoid is what you adjust to manually up line pressure. Which makes me think that maybe that's what the builder was talking about adjusting.
What do you guys think? Could it be the EPC solenoid? What's the rate of failure on these things?
I've got a 2001 4.8 and 4L60E swap in a 97 S10. Custom harness so it's 100% functional still being run by the 2001 silverado PCM.
Here's my issue, I had the trans totally rebuilt with a few upgrades like corvette servo, beast sunshell, better clutches, ect... When I picked the trans up, the guy said that he turned something up to make it shift harder. I don't remember exactly what he said though.
Anyway, I've got about 4k miles on the trans and it's acting REALLY weird. It used to hammer second and third and felt super crisp and responsive. Lately, it feels like it won't go into overdrive in the mornings when the trans is cold, second is no where even CLOSE to a firm shift accept for 1 out of maybe 10 1->2 shifts where it actually hits hard like it's supposed to. It feels like it lags on shifting gears sometimes.
It's really unpredictable. The weirdness varies each time it shifts. From what I've read, it sounds like it could possibly be an EPC solenoid issue. I also read that the EPC solenoid is what you adjust to manually up line pressure. Which makes me think that maybe that's what the builder was talking about adjusting.
What do you guys think? Could it be the EPC solenoid? What's the rate of failure on these things?
trans I dont know if you meant overdrive as in 4th or tc lockup.TC wont lock up till its warm,thats normal.As far as the 1-2 shift it could be a lot of diff things.EPC,1-2 accumalator,2 servo,2-4 band and on and on.......Best thing to do would have your trans mech to look at it.
TECH Apprentice
Joined: Dec 2008
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From: Westbank of N.O.
If it were mine, and I was just going throw parts at it.....I would pull then, replace the epc and pressure switch assembly.
Around here I would put a line press. gauge on it, but in the end would prob. need the 2 items I mentioned. I say this because u say it's unpredictable, shift firmness varies, and no 4th sometimes. 50.00 worth of parts, and some fluid/filter/pan gasket. BAM! Over in 45min.
Around here I would put a line press. gauge on it, but in the end would prob. need the 2 items I mentioned. I say this because u say it's unpredictable, shift firmness varies, and no 4th sometimes. 50.00 worth of parts, and some fluid/filter/pan gasket. BAM! Over in 45min.
Thread Starter
Teching In
Joined: Dec 2009
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I appreciate the input guys!
I was hoping to avoid having to taking it back to the builder. I have to take off work to go there and it's a hassle to deal with them sometimes.
I honestly can't tell when the TC locks up. Never really been able to distinguish that. HP tuners says that it's locking but I don't know how accurate that is. I do know that 3 or so times recently, it's not wanted to go into fourth until I let off the gas.
I've had transmissions go before but usually it's predictable and/or it progressively gets worse. I've never had one act like this before.
Sometimes it feels like it shifts gears too soon as well.
I was hoping to avoid having to taking it back to the builder. I have to take off work to go there and it's a hassle to deal with them sometimes.
I honestly can't tell when the TC locks up. Never really been able to distinguish that. HP tuners says that it's locking but I don't know how accurate that is. I do know that 3 or so times recently, it's not wanted to go into fourth until I let off the gas.
I've had transmissions go before but usually it's predictable and/or it progressively gets worse. I've never had one act like this before.
Sometimes it feels like it shifts gears too soon as well.
