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Discussion Starter · #1 ·
Okay so this about the 4th time I've put this transmission in this car. Full rebuild back in July all new clutches, plates, band, pump, the works. Couple months ago it started hissing between each shift and made a thread about it. Co-worker that built it tore it all back down and said he couldnt find anything wrong with it. Said it had to be the stall converter. Bought another Dacco Performance converter and put it all back in to find the same problem after it gets hot starts hissing between gears then slipping between gears then just lets go all forward and reverse gears. Let the car cool off and drives fine till it gets hot.

So then he tells me its gotta be the pump. Go to his house and pull the pump out of a known good transmission. I pulled the pump out this time and another coworker went ahead and pulled all the clutch packs out to inspect and they still look brand new. put it all back in with a new pump just to do the exact same damn thing. Except now it seems even louder and metalic noise in park/neutral after it starts to slip and let go. put it in gear and the noise goes away but then starts to hiss if you give any gas. At this point the car wouldnt move at all forward or reverse. Shut the key off for about 30 seconds then I can move the car around the lot again.

All the noise comes from right at the bell housing of the transmission.

Bout ready to throw my hands up shoot it with a 12 gauge and go find a T350 for all the time and money I have wasted.

Both pumps are PWM pumps even tho the car is non pwm. The valve body has a hole for the pwm but nothing in it nor a connector for one. He said it still wouldnt matter. Tired of this guy wasting my time and money
 

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I suggest you pm either dynamic396 or cahall, both transmission experts and see what they say about using a pwm pump in a non-pwm trans.
 

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Discussion Starter · #3 · (Edited)
Searched for a little bit earlier today when i noticed both pumps were pwm pumps. Some say its fine. Some say it burns the low/reverse clutches up. All clutches look brand new still and it went about 6-8 months with the first pwm pump in it. I dunno if i wanna waste any more time or money on it. Its been pulled out enough times already. Transmission guy txt me earlier said he would get me another transmission together but its probably going to be the same deal with mix matches parts from different years like before.

Im also leaving the dealership at the end of next week and starting a new job. So the car will be towed out of there or just drive it home if it blows up it blows up. So then whatever I decide to do with it next will be on the ground.

Thinking about buying th350 with 9" tailshaft and have someone else build it.
 

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Discussion Starter · #4 ·
One other thing Ill try is bringing my laptop up to work monday and log the car again with datamaster and see if it logs anything odd. Original builder txtd me earlier says its probably a hydraulic leak in the case since we eliminated the pump and converter. And all the clutches are still fine. He wants to see if he can find another case to swap whats good out of mine into it.
 

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Firstr thing is...You CANNOT put a PWM pump in a non PWM transmission. This is something anyone working on a 4L60E should know.
As far as the noise, it sounds like something around the forward drum is assembled wrong.
Before you blame the 4L60E, let's seriously look at who you're having work on it. I know it's tough to spend the money, but it might be time to take it to a professional.

Frank
 

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Discussion Starter · #6 ·
K. Guess maybe it is time to switch to another builder.

Kinda odd it ran 7 or so months with a pwm pump in it and I put it through hell too setup like that. Theres a couple performance transmission builders locally that im going to go talk to and go from there.

Coworker that built mine has been building gm transmissions for years but maybe he doesnt know all that he says he does.
 

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Discussion Starter · #7 ·
Im sure hes going to say hes never heard anything about it. So what happens when you do attempt to run a pwm pump in a non pwm transmission.
 

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leak in the TCC circuit.

Frank
 

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Discussion Starter · #9 · (Edited)
Thanks Frank. I feel a little better knowing that this is a good possibility. Was running out of ideas and bout ready to junk it all together.

Maybe I was just lucky that it went 7 or so months with a pwm pump before.

He was wanting to put everything out of my trans into a new case and claims we already eliminated a pump problem cause I just put a known good pump that he gave me. Apparently that wasnt the problem. Im gonna talk to some other popular builders around here this week and go from there. Thanks again for reading through my rambling thread.
 

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Didn't want to get myself into trouble by stating you shouldn't mix a pwm pump on a non-pwm car, but that confirms my suspecting that was the problem.

The 700r4, 4l60E family of transmissions have made many changes over the years, so mixing and matching different year parts is usually a no no. There are some newer parts that can be retrofitted, but most of the time, your builder needs to stick with the parts made for your year of 4l60e.
 

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Discussion Starter · #11 ·
Hes an older guy and not so great at txting but this is what he had to say about pwm pump causing leak in the tcc circuit.

They are wrong I can't tell u how many I have put together when u use pwm pump in a non Pam Trans u have to use pump and cover together not separate u most probably have a bad case

Then after I said leaks in the tcc circuit he said.

I already know since where the problem lies besides out of all that has a Pwm pump opposed to a non pwm that loss does not exists because the tcc locks the converter at 0. To 5 Rpms slippage the blocked off or in ur case a non drilled pwm circuit reroutes the fluid through tcc solenoid it has no option but to direct to the tcc hub within the converter this is not true about what u are reading on Internet
 

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Firstr thing is...You CANNOT put a PWM pump in a non PWM transmission. This is something anyone working on a 4L60E should know.
As far as the noise, it sounds like something around the forward drum is assembled wrong.
Before you blame the 4L60E, let's seriously look at who you're having work on it. I know it's tough to spend the money, but it might be time to take it to a professional.

Frank
My sentiments exactly... You simply cannot use a PWM pump in a non-PWM application. You'll end up with a hydraulic disaster on your hands...
 

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Discussion Starter · #14 ·
PWM (pulse width modulator) pump works with a PWM solenoid. The PCM provides a duty cycle to this PWM solenoid, which in turn regulates the pressure in the TCC hydraulic circuit, allowing the torque converter clutch to apply gradually. Instead of the older design with just off and on tcc apply.
 

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Discussion Starter · #15 ·
I know everyone has said its cause its the wrong pump, tho I beat the shit out of it for seven months built this way. Before i spend 600+ on parts lets just say it has the right pump and its not the problem

Would a faulty high res tps fault cause any of this. Or a faulty EPC solenoid. Ive read where tps failure will cause default max line pressure or even a failed epc will default max line pressure. I know the builder already added line pressure a year ago at the EPC
 

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Discussion Starter · #16 ·
Finally got the transmission fixed. The two pumps may have been bad or may have been the solenoids I changed. The original builder called and said he found me a known good non pwm pump. Swapped the pump and installed all new oem electronics and did not change line pressure in epc. Car actually drives like it has a stall now. Smooth shifts when cruising, nice and tight at wot, and no more 2-3 flare at wot
 
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