4l60e rebuilt 2-3 flare

[Hoosierlong90]

Truck is 94 K1500
New L31 tbi injected
Rebuilt 4l60e transmission

Trans flares 200-500rpm under moderate-heavy throttle.

Things done during build

• Sonnax smart shell kit
• Sonnax performance pack
• Sonnax heavy duty 3-4 clutch backing plate kit
• Vacuum tested valve body with Sonnax updates
• FLT blue printed performance pump
• New reverse input drum
• Extra wide 2-4 band (Red)
• B/W hi-energy 3-4 clutch pack
• B/W 29 element input sprag
• 4L65E low roller clutch
• 4L70E .63 ratio 2nd gear servo kit
• New torrington bearings
• New solenoids
• New manifold pressure switch
• New spacer plate
• New internal wiring harness
• New seals & gaskets

Things I have done to address flare
Check dipstick orientation
Transmission fluid is perfectly full
Changed ecm
Changed TPS and adjust accurately

I have went through 2 rebuilds already over the last 6 years. Truck has 37s with 4.88s. First trans, 4th gear went out. 2nd trans, planet broke. Both had Corvette servos.

This problem doesn't always happen either. For example- yesterday, first 3 shifts from 2nd to 3rd where perfect. Then the next 4 flared. From tuner pro, selonoid B looks to be turned off by the computer fine. I went ahead and replaced the computer to make sure.

PSI guage reads between 80-90 through gears 1-4. 100 cruising at 70. Reverse is 125ish. Haven't checked it at WOT because I don't want to burn the clutchs up. When I blip the throttle, PSI maxes out between 200-220.

Can someone please point me in the right direction of what this could be. It feels like a timing issue but it doesn't always happen, so I'm stumped. Could it be a faulty selonoid. And I know it's hard to pinpoint the problem without looking at it. I would take it back to the place that built it but he's almost 5 hours away so that would be 2 10 hour trips to go drop it off then pick it back up. FML

 

[NickTransmissions]

Truck is 94 K1500
New L31 tbi injected
Rebuilt 4l60e transmission

Trans flares 200-500rpm under moderate-heavy throttle.

Things done during build

• Sonnax smart shell kit
• Sonnax performance pack
• Sonnax heavy duty 3-4 clutch backing plate kit
• Vacuum tested valve body with Sonnax updates
• FLT blue printed performance pump
• New reverse input drum
• Extra wide 2-4 band (Red)
• B/W hi-energy 3-4 clutch pack
• B/W 29 element input sprag
• 4L65E low roller clutch
• 4L70E .63 ratio 2nd gear servo kit
• New torrington bearings
• New solenoids
• New manifold pressure switch
• New spacer plate
• New internal wiring harness
• New seals & gaskets

Things I have done to address flare
Check dipstick orientation
Transmission fluid is perfectly full
Changed ecm
Changed TPS and adjust accurately

I have went through 2 rebuilds already over the last 6 years. Truck has 37s with 4.88s. First trans, 4th gear went out. 2nd trans, planet broke. Both had Corvette servos.

This problem doesn't always happen either. For example- yesterday, first 3 shifts from 2nd to 3rd where perfect. Then the next 4 flared. From tuner pro, selonoid B looks to be turned off by the computer fine. I went ahead and replaced the computer to make sure.

PSI guage reads between 80-90 through gears 1-4. 100 cruising at 70. Reverse is 125ish. Haven't checked it at WOT because I don't want to burn the clutchs up. When I blip the throttle, PSI maxes out between 200-220.

Can someone please point me in the right direction of what this could be. It feels like a timing issue but it doesn't always happen, so I'm stumped. Could it be a faulty selonoid. And I know it's hard to pinpoint the problem without looking at it. I would take it back to the place that built it but he's almost 5 hours away so that would be 2 10 hour trips to go drop it off then pick it back up. FML

The low roller clutch is the same since the 700R4s; there's no 4L65e specific owc. Brand new solenoids are very rarely bad, same with the harness - all the stuff that should have been replaced looks like it was replaced and almost none of the above would cause your problem anyway, except what was done w/the 3-4 clutch pack and spacer plate.

Either you have too much clearance in that 3-4 pack and/or imbalance in 2-3 feed and band release orifices in the spacer plate. Under heavy-to-WOT throttle those imbalances reach a tipping point where no amount of compensatory actions taken by the ECM's transmission adapt strategies will fix it. It won't happen all the time but under WOT, if you don't have the thing mechanically calibrated just right, you'll have those problems...Clearance in the 3-4 pack should be no higher than .050 (would rather see .030-.040) and 2-3 exhaust and 2-3 feed orifices should be similar or identical in size.

As an aside, why did you install a .63 servo kit when you were previously running corvette 2nd gear servos, which were much better for your application (more apply surface = more clamping force, all other things equal)?
Did you think the loss of fouth gear or a broken planetary carrier had something to do with you using a 093 servo vs the stock 553? Or did someone tell you that?

 

[Hoosierlong90]

No reason behind the different servo. Just what was offered with the stage build I bought. Not opposed to installing one. Though 2nd gear hits good already. It shifts great to be honest with you, just drives me mad when I get the flare. I think the Detroit locker was contributing cause of planet failure. I put G80 back in.

I have much more HP now too. Around 300-325hp and 375-400torque compared to a dogged out stock power.

Builder says it may as well be something electronical. I feel like I have checked most those boxes, except harness which visually looks great but may not be the case.

Also should mention-
4th super hold servo was installed too
Speedo is accurate with adjustable VSSB
Shift points and converter points have been updated
Desired shift times have been adjusted with no effect
Adapt doesn't seem to ever work as far as I can tell when logging
Shift times for 2nd is .6-.7sec
3rd is .4-.6 when normal driving and a whopping 1.2sec when flare happens

F**k!!!

 

[NickTransmissions]

No reason behind the different servo. Just what was offered with the stage build I bought. Not opposed to installing one. Though 2nd gear hits good already. It shifts great to be honest with you, just drives me mad when I get the flare. I think the Detroit locker was contributing cause of planet failure. I put G80 back in.

I have much more HP now too. Around 300-325hp and 375-400torque compared to a dogged out stock power.

Builder says it may as well be something electronic. I feel like I have checked most those boxes, except harness which visually looks great but may not be the case.

Also should mention-
4th super hold servo was installed too
Speedo is accurate with adjustable VSSB
Shift points and converter points have been updated
Desired shift times have been adjusted with no effect
Adapt doesn't seem to ever work as far as I can tell when logging
Shift times for 2nd is .6-.7sec
3rd is .4-.6 when normal driving and a whopping 1.2sec when flare happens

F**k!!!

Thanks for the addl info but the likely causes are the same...You need to see how the above-mentioned orifices are sized in the plate as well as clearance in the 3-4 clutch pack.

The band is releasing before the 3-4 clutch pack is fully compressed hence your flare...I'd keep your same 2nd gear servo for now if it's shifting well from 1-2. The vette servo make it feel a bit firmer due to more apply surface area, though how much isn't known unless you install one.

Not sure why your builder thinks it's electronic unless there's some evidence to support (DTC codes, intermittent limp mode, etc).

 

[Hoosierlong90]

Thanks for the addl info but the likely causes are the same...You need to see how the above-mentioned orifices are sized in the plate as well as clearance in the 3-4 clutch pack.

The band is releasing before the 3-4 clutch pack is fully compressed hence your flare...I'd keep your same 2nd gear servo for now if it's shifting well from 1-2. The vette servo make it feel a bit firmer due to more apply surface area, though how much isn't known unless you install one.

Not sure why your builder thinks it's electronic unless there's some evidence to support (DTC codes, intermittent limp mode, etc).

Thanks Nick! You seem very acknowledable on these trans. I guess my next question would be to figuring out the clutch clearance? I assume it would have to be pulled apart to do so. Is there a diagram that shows where the band release orifices are located?

I think it's time I start to learn how to build these 60s. I am very intrigued. Can you point me to a good guide book?

Thanks!

 

[NickTransmissions]

Thanks Nick! You seem very acknowledable on these trans. I guess my next question would be to figuring out the clutch clearance? I assume it would have to be pulled apart to do so. Is there a diagram that shows where the band release orifices are located?

I think it's time I start to learn how to build these 60s. I am very intrigued. Can you point me to a good guide book?

Thanks!

Yep and can do you one better: my 4L60E playlist on YT. Its full of vids on the 4L60Es and includes two detailed tear down and inspection vids, several reassembly videos as well as topical segments covering various aspects of the 4L60E family of transmissons.

Grab the ATSG manual as it has everything you'll need as procedural info diagnosis and troubleshooting, torque, end play and clearance specs among other things. Pairs great with my content.

Here's a pic of the 4L60Es spacer plate with everything labeled. The band release and 2-3 feed should be similar in size to each other. My guess is that they are on yours but the 3-4 pack clearance is excessive and load release springs were reinstalled (i always leave them out unless rpms reg exceed 6000 and clearance is .030-.040 in the 3-4 pack.

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[Hoosierlong90]

Yep and can do you one better: my 4L60E playlist on YT. Its full of vids on the 4L60Es and includes two detailed tear down and inspection vids, several reassembly videos as well as topical segments covering various aspects of the 4L60E family of transmissons.

Grab the ATSG manual as it has everything you'll need as procedural info diagnosis and troubleshooting, torque, end play and clearance specs among other things. Pairs great with my content.

Here's a pic of the 4L60Es spacer plate with everything labeled. The band release and 2-3 feed should be similar in size to each other. My guess is that they are on yours but the 3-4 pack clearance is excessive and load release springs were reinstalled (i always leave them out unless rpms reg exceed 6000 and clearance is .030-.040 in the 3-4 pack.

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Well Nick, I think I figured out the problem. When I installed the new deep pan, I didn't have the filter extension seated all the way into the pump hole.

 

[NickTransmissions]

Well Nick, I think I figured out the problem. When I installed the new deep pan, I didn't have the filter extension seated all the way into the pump hole.

Deep pan? Did you mention that above? I quickly scanned your OP and didn't see it but could have missed it being mentioned elsewhere...yea that will do it...pump was starved for fluid so line rise suffered along shift quality...hopefully no damage was done to anything...

 

[Hoosierlong90]

Yeah deep pan...I spaced it when I wrote the op.

I started double checking everything I did. I had it on the 1st lip, not the 2nd so I imagine it was too close to the bottom. Or didn't have enough seal around it for suction.

I hope I get some decent miles out of it, I guess I'll find out. Psi was still there, just not enough.

I hope this helps someone in the future.

 

[Hoosierlong90]

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