4l60e no 1st or 4th, ez tcu

[618 Syndicate]

A fuse can do it, it's one of many causes but the bottom line is that Shift Sol A is on in first and fourth, shift sol B is on in 1st and 2nd, off in 3rd and 4th so if he's missing 1st and 4th, its due to shift sol A not performing or being enabled to perform, hence "left the chat"

Why it's not performing is the question.

Also, the 2-3 shift is not "mechanical" per say as all forward pattern shifts happen under the direct command and control of the PCM and it's trans control strategy logic. It just so happens 3rd gear occurs when both solenoids are off but they are off because the PCM commands both off, not for any other reason, when everything's working correctly.


If you rule out all electrical/electronic causes (including the PCM itself), by whichever means, then it's time to drop the valve body...

Beyond that i cant let you know anything as im not there with you. But if i was, id check the fuse like 618Syndicate mentioned, test the solenoids then harness then vehicle harmess and pcm for voltage and continuity. Id then take it for a drive with a scan tool showing live trans data and command it into 1st to see if the pcm responds. If it does, pcm shows im in first but im actually in second then im looking internally into the trans.

Pre-96 4L60Es can shuttle back and forth between 2nd and 3rd while in limp mode. I rebuilt a 93 for someone years ago and installed a solenoid that was bad out of the packaging. He had the same symptoms you do. Just remembered this as i was typing.

Lastly- make sure you have a 93-95 3-2 control solenoid, not a 96-08 installed. Shot in the dark but that could also cause your problems.

Mechanical was the term the guy used, I didn't ask for details but it made sense how he explained it. Also the truck in question is an 07 classic, so an 06 functionally. It had 2-3 and R, so evidently the shifting without power isn't limited to the the early 4L60e models?

 

[NickTransmissions]

Since you mention it, I put a 1996 pwm pump, and 1996 valve body with the 1996 separator plate in 1994 case. Id imagine the valve body i got should have all 96+ solenoids for the ones that matter. I did notice the shift solenoids that where replaced where the old style. But I'm controlling it with a eztcu so it really doesn't matter what year the tranny is as long as it's not 2009+. And my first post has the info where a tcu is commanding low 1 but not going in 1st. Same thing with 4th, it gives me a live data screen. Fuse is good, I took it out the other day to check the ignition switch. The ez tcu will say comm error when 12v switch is lost

You converted it to a 96-00 vintage, which is fine for most aftermarket controllers but not for factory ECMs. I have no idea what an 'eztcu' is but as long as it doesn't require a manual lever position sensor, it's probably fine. The cases themselves didn't change between 93-97 insofar as the worm tracks or pump-to-case channels, just the holes for mounting the MLPS starting with either L95 or 96. The shift solenoids never changed, just the 3-2 control solenoid starting in 96 and the PWM solenoid between 95 and 96+.

I didn't read your first post beyond the title so "forgive" me.

If your data shows the eztcu thinks the transmission is in 1st gear but you're actually in second then something's wrong mechanically, either in the VB or case so be 100% sure of your diagnostics...If you are, time to start digging back into it. First place to investigate is the 1-2 shift valve then 2-3 shift and shuttle valves...It may also be worth vac testing the valve body, particularly the AFL valve...If the AFL bore wear is pronounced enough, you'll also have 2nd gear starts. Also check the spacer plate for anything unusual (stuck check balls, unusual orifice re-sizing, etc). Check the 1-2 accumulator to make sure the seal isnt missing or broken.

Another thing to do is conduct a line pressure test - do that first before dropping the pan. I'd be curious to see if you have unusually low pressures for whatever reason. Again, shot in the dark but these are all things that can cause wrong gear starts.

You built this trans, right? What was the reason it came out for overhaul (most cases, it's the 3-4 clutch pack). Did you notice anything overly noteworthy or unusual on any of the parts when tearing it down/inspecting it?

If I think of anything else, I'll let you know...Interesting case, that's for sure...

Mechanical was the term the guy used, I didn't ask for details but it made sense how he explained it. Also the truck in question is an 07 classic, so an 06 functionally. It had 2-3 and R, so evidently the shifting without power isn't limited to the the early 4L60e models?

Yea, it sounds like semantics but it's an important distinction. To be clear, I'm not criticizing you, just pointing it out in the event others read and get the impression the 60 can be operated mechanically some how... And yes, some of the 2007 model year vehicles equipped with 4L60Es didn't have the turbine speed sensor (TSS). Lucky for those owners; if that stupid TSS (aka ISS) fails, you can't simply drop the pan to replace it.

 

[tuffy331]

You converted it to a 96-00 vintage, which is fine for most aftermarket controllers but not for factory ECMs. I have no idea what an 'eztcu' is but as long as it doesn't require a manual lever position sensor, it's probably fine. The cases themselves didn't change between 93-97 insofar as the worm tracks or pump-to-case channels, just the holes for mounting the MLPS starting with either L95 or 96. The shift solenoids never changed, just the 3-2 control solenoid starting in 96 and the PWM solenoid between 95 and 96+.

I didn't read your first post beyond the title so "forgive" me.

If your data shows the eztcu thinks the transmission is in 1st gear but you're actually in second then something's wrong mechanically, either in the VB or case so be 100% sure of your diagnostics...If you are, time to start digging back into it. First place to investigate is the 1-2 shift valve then 2-3 shift and shuttle valves...It may also be worth vac testing the valve body, particularly the AFL valve...If the AFL bore wear is pronounced enough, you'll also have 2nd gear starts. Also check the spacer plate for anything unusual (stuck check balls, unusual orifice re-sizing, etc). Check the 1-2 accumulator to make sure the seal isnt missing or broken.

Another thing to do is conduct a line pressure test - do that first before dropping the pan. I'd be curious to see if you have unusually low pressures for whatever reason. Again, shot in the dark but these are all things that can cause wrong gear starts.

You built this trans, right? What was the reason it came out for overhaul (most cases, it's the 3-4 clutch pack). Did you notice anything overly noteworthy or unusual on any of the parts when tearing it down/inspecting it?

If I think of anything else, I'll let you know...Interesting case, that's for sure...


Yea, it sounds like semantics but it's an important distinction. To be clear, I'm not criticizing you, just pointing it out in the event others read and get the impression the 60 can be operated mechanically some how... And yes, some of the 2007 model year vehicles equipped with 4L60Es didn't have the turbine speed sensor (TSS). Lucky for those owners; if that stupid TSS (aka ISS) fails, you can't simply drop the pan to replace it.

I didn't take the transmission apart myself, originally took it to a transmission shop and they quoted me 4k, said it had a bad pump and a warped valve body. Didn't do that and ended up sitting in the bed of my truck for over a year disassembled, brought it into my work to use a parts washer to clean the case, then I replaced everything in the case with new parts, only thing I reused was the shift linkage. I cleaned it really good with brake cleaner and nylon brushes after parts washer. Replaced the cooler and cooler lines. New torque converter. I really do appreciate your input, just want to make sure to be clear. Will definitely update
Thanks

 

[NickTransmissions]

I didn't take the transmission apart myself, originally took it to a transmission shop and they quoted me 4k, said it had a bad pump and a warped valve body. Didn't do that and ended up sitting in the bed of my truck for over a year disassembled, brought it into my work to use a parts washer to clean the case, then I replaced everything in the case with new parts, only thing I reused was the shift linkage. I cleaned it really good with brake cleaner and nylon brushes after parts washer. Replaced the cooler and cooler lines. New torque converter. I really do appreciate your input, just want to make sure to be clear. Will definitely update
Thanks

They quoted you $4,000 for a bench/carry build? My bill would be around $2350ish for the same carry out rebuild, replacing the bad pump and valve body included.

You have some electrical or mechanical problem and it's in the 1-2 or 2-3 electro-hydraulic circuit. Something is allowing 2nd gear apply oil to flow to the servo piston when your tcu is commanding first gear.

When the 1-2 shift valve is at rest position, it's enabling apply oil to flow into the 2nd gear circuit so the servo can apply the band. However when you start the truck, shift into "D", drive oil is sent to the forward clutch pack AND the pcm fires solenoid A to stroke the 1-2 shift valve inboard against its spring. This cuts off 2nd apply oil, allowing you to have first gear instead of 2nd (when an upshift to 2nd is commanded, the tcu simply cuts power to Sol A, allowing the valve to reset and open the circuit to the band servo, giving you 2nd gear). This last bit doesnt seem to be happening as described, band is applied as soon as drive oil enters the forward circuit. Alternatively, if you left the seal off the 1-2 accumulator piston, apply oil would flow right past the piston and apply the band as well.

Since you rebuilt the trans, figured you should know a bit about the relevant hydraulic theory to help you in your diagnosis, in the event you didn't already know.

 

[tuffy331]

They quoted you $4,000 for a bench/carry build? My bill would be around $2350ish for the same carry out rebuild, replacing the bad pump and valve body included.

You have some electrical or mechanical problem and it's in the 1-2 or 2-3 electro-hydraulic circuit. Something is allowing 2nd gear apply oil to flow to the servo piston when your tcu is commanding first gear.

When the 1-2 shift valve is at rest position, it's enabling apply oil to flow into the 2nd gear circuit so the servo can apply the band. However when you start the truck, shift into "D", drive oil is sent to the forward clutch pack AND the pcm fires solenoid A to stroke the 1-2 shift valve inboard against its spring. This cuts off 2nd apply oil, allowing you to have first gear instead of 2nd (when an upshift to 2nd is commanded, the tcu simply cuts power to Sol A, allowing the valve to reset and open the circuit to the band servo, giving you 2nd gear). This last bit doesnt seem to be happening as described, band is applied as soon as drive oil enters the forward circuit. Alternatively, if you left the seal off the 1-2 accumulator piston, apply oil would flow right past the piston and apply the band as well.

Since you rebuilt the trans, figured you should know a bit about the relevant hydraulic theory to help you in your diagnosis, in the event you didn't already know.

So I'm guessing the manual valve also changes oil flows too? I'm thinking what if somewhere in the fluid circuit that is controlled by the manual valve circuits causing no 1st or 4th. If a solenoid blocks off fluid to the band for 1st but also blocks off the same fluid for the band in 4th gear, then fluid would be getting to the band for 4th through another way, I was thinking the manual valve changes flows. Idek man, this **** is confusing, leaking into the band in 1st and not for 4th. Maybe I got 2 separate problems lol, I'll check the solenoids for grounds and then go through what you've discussed

 

[NickTransmissions]

So I'm guessing the manual valve also changes oil flows too? I'm thinking what if somewhere in the fluid circuit that is controlled by the manual valve circuits causing no 1st or 4th. If a solenoid blocks off fluid to the band for 1st but also blocks off the same fluid for the band in 4th gear, then fluid would be getting to the band for 4th through another way, I was thinking the manual valve changes flows. Idek man, this **** is confusing, leaking into the band in 1st and not for 4th. Maybe I got 2 separate problems lol, I'll check the solenoids for grounds and then go through what you've discussed

There are two applied elements in the servo bore, the 2nd gear piston and 4th gear piston...There are also two different sets of valve trains for each...The 3-4 relay and 4-3 squencing valve along with the 3-4 upshift valve dictate what happens in 4th and the 4-3 downshift. The 3-2 control valve, 3-2 downshift valve, 2-3 shift and shuttle valves along with the 1-2 shift valve are in play between gears 2 and 3.

It's possible you simply received a bad valve body. It wouldn't be the first time one was found to be bad out of the box or wherever it was sourced from...Did you have these same issues or anything like them prior to the rebuild and 96 parts being installed?

Yes - rule out all electronic/electrical causes then move to the mechanical stuff.

 

[tuffy331]

There are two applied elements in the servo bore, the 2nd gear piston and 4th gear piston...There are also two different sets of valve trains for each...The 3-4 relay and 4-3 squencing valve along with the 3-4 upshift valve dictate what happens in 4th and the 4-3 downshift. The 3-2 control valve, 3-2 downshift valve, 2-3 shift and shuttle valves along with the 1-2 shift valve are in play between gears 2 and 3.

It's possible you simply received a bad valve body. It wouldn't be the first time one was found to be bad out of the box or wherever it was sourced from...Did you have these same issues or anything like them prior to the rebuild and 96 parts being installed?

Yes - rule out all electronic/electrical causes then move to the mechanical stuff.

No, this is the first time I've used this tcu and 96 valve body, transmission was controlled by the factory pcm before swap

 

[NickTransmissions]

No, this is the first time I've used this tcu and 96 valve body, transmission was controlled by the factory pcm before swap

Do you still have the other valve body?

 

[tuffy331]

Do you still have the other valve body?

Yep, that's the one I'm gonna clean up and reuse if I can't figure it out, when I opened the pan to drain the oil it looked like a 96+ valve body, if it weren't a pwm style valve body could I still use it with the pwm pump and separator plate?

 

[tayto]

what was the part # for the internal harness you replaced?

unless you have the wrong separator plate and/or gaskets using a pwm pump and 96+ valve body should work in your 94 case. I don't believe you can use a pwm pump with a non-pwm valve body. this sounds like an electrical issue to me

EDIT: did you use manual valve out of the 94 or 96 valve body?