4L60E PWM pump and valve body compatibility

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I have a early one piece case 4L60E Tag 3TAD(1993 4.3L truck). My research indicates that this tag is a non PWM transmission
It has a PWM pump and the valve body has a PWM solenoid for the torque converter circuit.
I have no knowledge of the history or who put it together.
Are these parts even compatible?
If so are there modifications needed to allow the torque converter lock up to function in "on /off" mode with a 12 pin harness plug computer?
As an aside....when did GM start using pulse width modulation for the 4L60 torque converter clutch apply?
Thanks to any responses in advance.
 
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PWM debuted in 1995 for passenger cars (B-body, F-body, & Y-body) & 1996 for C/K truck chassis. 1995 PWM units are a one year only unit as in it uses a PWM 3-2 downshift solenoid & a PWM TCC Solenoid. 1996 & up uses a on/off 3-2 Solenoid & a PWM TCC Solenoid.

One can mix & match parts to a certain degree.....

*If you want to use a '93/'94 unit on a '95 PWM vehicle......Use a PWM Pump & a '95 ONLY valve body.

*If you want to use a '93/'94 unit on a '96 & up PWM vehicle...Use a PWM Pump & a '96 & up valve body.

*If you want to use a '95 PWM unit on a '93/'94 vehicle, Ground the PWM TCC Solenoid so it activates anytime the key is on. OR swap in a '93/'94 valve body.

*If you want to use a '96 & up PWM unit on a '93/'94 vehicle, Swap in a '95 valve body & Ground the PWM TCC Solenoid so it activates anytime the key is on. OR swap in a '93/'94 valve body.

*If you want to use a '93/'94 unit on a '96 & up vehicle, Swap in a '96 PWM pump & valve body.

There are 3 different separator plate's.....'93/'94.....'95.....And '96 & up & must be kept with their respective valve bodies.

You CANNOT run a PWM 3-2 Solenoid with on/off 3-2 Solenoid programming or vice versa as it WILL cause the 3-4 clutch to prematurely fail.
 

94TBI

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OK thanks.
Specifically I have a 1993 Blazer(full size) with a 5.7L.
It has a 16168625 ECM that has a 12 pin transmission plug hence no PWM torque converter but it has a PWM 3-2.
The transmission case is stamped 3TAD0420 on the pan rail passenger side rear(the actual Tag is missing).

So after investigating further what I have is a 1993 case with a 1995 valve body(3-2PWM and TCCPWM) and a PWM pump.
The separator plate has letters MU stamped in it and I assume that is the plate identifier code. I cant find any information searching the internet on plate ID however.

Is the PWM pump OK on a 1993 case?

So the closets scenario is your 3rd option (95PWM unit on a 93-94 vehicle) and grounding the PWM TCC solenoid which I guess is the side of the circuit that would be controlled by the ECM and it has key/on hot on the other side......as long as the PWM pump is good on the 1993 case.

What is different about the PWM pump verses non-PWM pump?
 
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PWM pumps are ported a little differently to allow better control of the converter clutch. Running a PWM pump in a Non-PWM application is fine.....However you cannot run a Non-PWM pump in a PWM application without modification to the TCC Regulator valve.
 

94TBI

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OK thanks. So as long as I make sure that I have a 1995 separator plate it sounds like this combination will work.
Am I correct in guessing that the 2 letter code stamped on the plate is the identifier? Worst case I will just get a trango plate for a 1995.
 

94TBI

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I hate to bug you but did you happen to check the MU 4l60 plate code?
 
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Plate code MU is for a '95 model......

kQrRLAH.jpg
 

94TBI

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From looking at the 4l60e hydraulics it seems TCC PWM solenoid modifies AFL oil to the be used as a signal to regulate line pressure oil lower for torque converter apply. I have seen guys leave off the end o ring of the TCCPWM solenoid and groove the land in between to allow AFL oil to pass at full pressure providing a constant pressure signal to the converter regulator valve. This would negate the need for the solenoid all together except as a end plug.
 
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I don't see why that wouldn't work!

You can also pin the TCC Regulator Valve against the Bore Plug using a spacer between the Regulator Valve & Isolator Valve. On Later models ('98 & up) with 3rd Type Regulator/Isolator Valves......We use a Inner Pump Slide Spring between the Regulator & Isolator Valves, The spring coil binds & acts as a solid spacer.
On 2nd Type Regulator/Isolator such as a '95.....I machine a spacer, But I bet a spacer could be cut from a piece of 3/8" hard line.
 

94TBI

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That seems like it would eliminate afl regulation and send line pressure to the converter though.
 
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Correct.....Which I've never had an issue with. TransGo shift kits do the same thing with their TCC Regulator Valve.

If you feel uncomfortable with that, I understand! But full AFL even with the balance feed will shift the regulator valve all the way to the bore plug assuming the bore is in good shape......If you have wear, You may not have enough TCC apply pressure.
 

94TBI

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I looked at the Transgo shift kit instructions on their website.


I see exactly what you are talking about with the ISO-CONV valve on page 4 of the instructions.
They have 2 line ups: 1st uses a spring like you mention to push the valve all the way against the end plug but the 2nd line up uses a spacer allowing the valve to shuttle based on AFL and feedback oil.
It looks to me that if I modify the TCCCPWM solenoid to eliminate PWM and send full AFL pressure signal to the valve and use the 2nd transgo line up using a spacer instead of spring that the wider land Trasngo valve/spacer line up would help eliminate cross leak from wear and also allow full pressure AFL regulation for TCC apply.
To me this seems like the best of both worlds without having to spend "Sonnax" level money.
 
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