Hello everyone,
Hoping to learn and get some ideas about what happened to my 4l60e pump in my truck. Shes a big girl. 5500lbs. ~500 fwhp 6.0 swap in a 2wd Suburban. I lost my 3/4 clutch pack in a spirited romp from a stand still. 3/4 let go in 1st gear about 5500 rpm and I figured it was the pump. Transmission is not stock. Please see my build here. Line pressure at idle was 150psi ~140 degrees with ECU connector unplugged. ECU plugged in at idle and 160 degrees. P:60 N:60 D:60 R:75. Force Motor Current test with HP Tuners was unresponsive. Pressure stayed at 125psi from 0.02-.0.98 amps at about 150 degrees. Each solenoid possessed an ohm reading within spec testing with pigtail while valve body was still in the pan. Yanked it and tore it down and all clutches/steels were completely fine (20k miles) except the 3/4 pack which was toast. I built this transmission with full credit and assistance from this forum and Dana from PBA who helped me a ton, but sourced a pump from a reseller. I've had good success with them, so I think this is on me as you will see from the photos below and/or my PCS crapped out and starved the pump. I pulled the PCS and it fit tight in the valve body bore and the screen was clear. Some clutch material in pan, but just enough to write my name. Fluid not terribly burnt at all. Better than I expected. I have a huge cooler on the truck and the trans rarely saw 180 degrees. Circle D billet 3200 flash stall. Pump has the Sonnax oversized pressure regulator valve #77917-07 and the .500 boost valve (generic or maybe Transgo). Not Sonnax so not with the o-rings. 13 vane. You will see in the photos below that I could have done a better job with my converter spacing. Rest assured this will be addressed on reassembly. So my question is: Did I screw up my pump because of my converter spacing? Or did the PCS starve the pump and score the front half? Or something else? I appreciate all opinions and feedback...good or bad.

Circle D Billet TC hub: Nothing in the photo catches a finger nail. All witness marks.


Pump rotor: You can see the witness marks where the converter hub engaged the pump rotor.


View of rotor and hub to get an idea of the witness marks in relation to the hub.


Now Using witness marks as a guide, this was the rotor-pump engagement.


Front bushing of pump


Front half of pump. There is definitely some gouging you can feel here.


Rear half of pump. Just witness marks here. Feels very smooth.


Pump slide


Thank you.

 

What makes your think the PCS can starve the pump?

 

Hi Jakeshoe,
Just a guess. I was going off the PCS not responding to the the FMC test in HP Tuners. That's why I posted here. So I can learn.

Editing and adding to my response:
Jakeshoe,
Now that you actually made me think about my offered hypothesis with the PCS being a contributor to pump failure... I see that was a pretty dumb statement to make. Thank you. It makes sense that the PCS, good or bad, would not affect the pump at all. Pump function is independent of any electronic management. Learning......

 

I know this is a dumb question, but was the filter in place? Did you have the right fluid level?

 

Dixie,
Not a dumb question at all. Filter in place and secure. After the failure I checked and the fluid was 3/4 quart low. Still between the dots, but low. It's a truck pan so it's the deeper design. Having said that, if this is the cause of the failure and it's that simple, then that's good to know and something I will not be careless with in the future.

 

While being low is bad , With the deep pan and assuming proper filter doubtful is was your issue nor was the pump . The PCS is likely bad or filter clogged based on your amp test, But some other questions come up about the build, Did you replace the bore plugs FWD and 3-2 ? On the reman pump orringed boost valve?
The 150 max line seems low to me I like to see at least 200 harness unplugged and about same WOT plugged in.
But since the band shows no sign of slipping I would think a leak in the 3-4 clutch circuit accompanied with a PCS failure. The 3-4 are pretty sensitive to pressure issues since they have comparatively little friction area and less heat dissipation. So they tend to go first in low line scenarios, Also what did filter in pump look like -trash in it?- side blown out ? I ask cause the small scratches in pump face though hard to determine with a photo might just be trash that came though particularly if screen side blown out from a possible converter failure, This will block the screens for the PCS along with the main filter.

 

Hi Frank,
Thanks for the input!!
I will vacuum test the valve body for healthy vacuum readings on all circuits.
I will air test the input drum separately and on the pump to verify piston functionality.
All teflon seals looked good on input shaft and pump.
Screens of the PCS were clean.
Main filter clean.
Scratches on the front half of pump are deep enough to catch a fingernail in several places.
Stator side of pump is smooth.
Will replace PCS with new older style.

Yes 150 psi with harness unplugged is low and wide open throttle in 1st was 75-80 psi. Not good at all.

Here are the answers to your questions.
Q: Did you replace the bore plugs FWD and 3-2 ?
A: Yes. Sonnax #77754-21
Q:On the reman pump O'ringed boost valve?
A: No. Does not have O'rings. It's the Transgo .500 boost valve Thinking I'll be adding the Sonnax boost valve on next pump.
Q: What did filter in pump look like?
A: See pic below. All sides of screens intact and not blown out.