LQ4-E39

iTrader: (3)

Donor trans is a 2000 4L80E from a 3500 Quad cab Chevy. It's installed in a 2002 Silverado RCSB with a 4.8 that originally ran a 4L60E.

Some background:

When I bought the trans used, the fluid came out nice and red and clean, minimal amount of sludge on the magnets. I installed a Transgo HD2 kit per the sloppy video and have it behind a Jake's 3200 street converter. When installing the converter I dumped a couple quarts of fluid in it. I made sure to seat the converter all the way in, but had to pull it forward to reach the stock 4.8 flexplate. I also had to elongate the holes on the stock flexplate to get it to match up to the converter.

Obviously I had to segment swap the tune, so I grabbed a 5.3/80E tune and used that to do the segment swap. The tune seemed to take it fine as it shows up as a 4L80E and reflects the 80E gear ratios. Also moved the pins around in the round connector and wired in a new pigtail to connect to the forward speed sensor (input).

I just fired the truck up for the first time today and it doesn't move in any gear. I dumped in 8 additional quarts before starting the truck and the fluid level doesn't move whether the truck is running or off. As a sanity check I pulled the pressure side of the cooler line at the cooler and have no fluid flow. I suppose I could pull that line at the trans to make sure it's not blocked, but it's a new ACDelco line so I can't imagine it's clogged.

Another hint may be that HPT Scanner shows it's always in 2nd gear regardless of where the selector is. The PRNDL indicator on the dash shows it going from Park down to 2nd just fine.

Pic just to have a laugh since I am pretty pissed at this thing right now



In terms of troubleshooting I am thinking the following:

Pump is not turning because converter isn't seated all the way? Despite being bolted up to the flexplate?
Should I unbolt the converter from the flexplate and seat it all the way in to measure converter pad to bellhousing flange distance?
Would incorrect wiring and or bad segment swap cause HPT Scanner to show trans being in 2nd all the time?

I am really hoping I don't have to pull the trans again as it was a bitch to get it in alone.

In case in matters the tune is attached. Thanks in advance as always .

madmann26

iTrader: (7)

You need to put a line pressure gauge on it.

LQ4-E39

iTrader: (3)

Where does the line pressure gauge attach to? I already removed the pressure side of the cooler port and had no fluid coming out.

madmann26

iTrader: (7)

Driver side of the trans. There is a port with a plug in it, about halfway up the case.

MaroonMonsterLS1

Why would he need a line pressure gauge if it's not pumping any fluid?
yes you need to re-measure the converter clearance. Also make sure the pilot is engaged. If you didn't use an adapter bolted on the flexplate then the pilot is likely not engaged.
No part of the tune will cause this issue. Even with the connector unplugged on the side of the trans...it will pump fluid and you will have 2nd and reverse.

LQ4-E39

iTrader: (3)

The plot thickens. No damage to pump, no scratches that can even catch a finger nail. The converter snout looked fine and I measured the gap between bellhousing flange and converter pads at just over 1".





















Scratching my head here. Was it just low on fluid? If so, why did the fluid level not go down on the dipstick with the engine running?

The only other thing I can think of is that I was running a dished flywheel with no spacer, which Jake's Performance told me would work. I will be installing a flat flexplate with spacer.

LQ4-E39

iTrader: (3)

Transmission in, filled up with 4 quarts. Started it up, Continued to add fluid. At no time did any fluid come out the cooler pressure port so I still have no pressure. To make sure I had enough fluid I kept adding oil until it started to dribble out the breather up at the bellhousing, meaning the case was full. I pulled the pan and checked the filter (which was new), nothing unusual, no clogs or debris. At this point I'm stumped.




Is there anything electrical that might cause the pump to bypass internally? Solenoids?

MaroonMonsterLS1

so, to fill the case you added...18-22 qts?
If that's the case...then it would pump without a filter in it at all because the sump would be covered.
Converter installed in the trans has 1.1xx clearance from the bellhousing flange right?
If so...how much clearance between the converter pads and the flexplate?
If there is too much clearance to the flexplate, you will pull the converter forward and disengage the pump gears

LQ4-E39

iTrader: (3)

I put in 4-5 quarts, started it, and then immediately started to fill it with 4 more quarts.



I can’t say if the case was filled, all I know is the breather vent up by the bellhousing was puking fluid. To me that indicates an overfilled transmission that isn’t picking up oil from the pan.



To answer your other questions:

I have checked all the basics. The converter pads are 1.125” from the bellhousing flange, verified with calipers. It’s a brand new Jake’s converter.

With the converter all the way into the trans, and trans installed, the converter pads are just under 1/8” from the flexplate. I pulled it forward less than 1/8” to bolt up to the flexplate.

The flexplate is this one, with the spacer preinstalled on the converter side. The flexplate was clearly stamped “engine side” and I made sure to install it with that facing the crank.


2002 4.8 short crank -> Flat 6.0 flexplate -> spacer.



I am installing a new ACDelco filter tonight and inspection the pressure relief valve to see if it’s bound up. I supposed I could also run a tube from the pickup hole down to a bucket of fluid to eliminate the possibility of a bad filter/pickup.

madmann26

iTrader: (7)

Might be a stupid question,

What does the snout on your converter look like?