4L80e install - Questions

[critter]

I did not intend to bother Bryan today but he called last night and asked if we could work on it today. He has a busy week next week and needed for the car to be gone or at least be able to move it without pushing it.



We got it all back together. The good news is that it pulls like it should now. The bad news is that I can't get it to change gears until it hits 3000rpm. I know I'm doing something wrong in programming the TCU and I've sent the TCU setup and the data log to TCI for their input. I'm open to thoughts.

[critter]

The frustration level has hit 10. Even after triple checking the TPS voltage and reprogramming the TCU it's still slipping and not shifting. The fluid is starting to have a slight burned smell again. No more driving it for data logging. I'm about to put that TH400 back in it. I can't afford another transmission rebuild.

I'll send in the data log I made from tonights drive tomorrow but it appears to me that the TCU line pressure DROPS when TPS voltage goes up. Am I reading this incorrectly? The value is 60 at idle and goes down on that gauge as RPM and TPS voltage increase. I don't understand.

This appears for all the world like a low pressure situation. The car goes solidly in to gear in reverse and drive. You can take your foot off the brake and it move just like you'd expect. As soon as I apply throttle it begins to slip and it never shifts out of first gear.

[critter]

Just to follow up this thread, Chris from TCI did contact me by phone and has gone over the data logs with me. He says it appears the TCU is doing what it should but he has tweaked the TCU file for me. I'll upload that when I'm back in the shop.

The transmission builder insists that this is a TPS issue, even though the TCU is seeing the voltage. I asked another builder who specializes in performance 4L80e transmissions (Jake). He's asking me to run figures with a pressure gauge because he suspects pump problems, even though it has been rebuilt.

My plan is to double check the hook up of the wiring harness and then hook up the gauge and run Jake's recommended test for line pressure. Then I'm going to replace the TPS, TISS and TOSS.

[critter]

Just to keep this one man thread rolling...

I got a gauge on it tonight.

With the harness hooked up:
Park and Drive - 0-10psi (WTF?)
Reverse - 50psi

With the harness unhooked:
Park and Drive - 150psi
Reverse - 300psi

[critter]

I spoke with Jake Shoemake today. While he thinks it could be the force motor (Pressure Control Solenoid) he recommended I call Powertrain Control Solutions and ask their advice. They make the TCI controller it seems.

Their tech was most helpful. His advice was to look at the harness first. He says that the TCU seldom has problems but if the harness Ohms out correctly they'd be happy to test it for me. That's good customer service.

[critter]

The harness ohm'd out perfectly. Tomorrow night's project is to reinstall the harness and check the amperage output that would be send via TPS position to the force motor (Pressure Control Solenoid) inside the transmission.

[critter]

To bring everyone up to speed on where I am with this project, I ran the tests that TCI asked me to run with the TPS and reported those pressures. I then decided I had valve body issues based on their advice. Jake and I talked and he suggested a new boost valve and spring. Jake did NOT build this transmission. I figured if I was going in to do that I might as well ad a shift kit and Jake is supplying that.

In the interim, I ran the pressure test Jake asked for that required removing the harness and running the RPM up to about 1500. When we did that we had 170psi in Park and Drive and 320psi in reverse. That is exactly what we should be seeing according to the ATSG and Jake.

I've run that back at TCI for their comment since, when you take their electronics out of the equation, the damned thing is doing exactly what it should.

[79-TA]

Just wondering . . . since you're working out the bugs with getting the more modern electric transmission in a 2nd gen, how hard would it be to step up to a 6L80? I assume (but do not know for sure if) it is the same size as the 4L65 and 4L80.

Anyway, keep up the good work!

[critter]

All it takes is $$$. More than I have. ;)

Then again, I'm not sure any of the aftermarket controllers will work with it.

I'd settle for this one working.

[Jake's Performance]

The 6L80/6L90 series trans are LARGE even compared to a 4L80E.
They look like an Allison.

They also have MUCH more complex electronic controls and the controller is internal to the transmission.

I don't believe they will ever make a good performance transmission due to the design. It is a synchronous shift unit so every gear must be timed for proper shifting.

They shift like a school bus, dump truck, garbage truck... take your pick.

[critter]

I intended to install the new boost valve and shift kit today but I woke up feeling like crap and called Bryan. He had other things to do today as well. I borrowed my old trailer and and brought it home so I could work on in next week.

The funny thing is, when I backed it out of the shop it felt pretty good. Pulling it on the trailer it felt better. Getting it off the trailer and into the garage didn't feel bad either. That's the first time the car has been moved since I put "MY" program in the computer. Screw TCI. I'm going to do some tweaking with the tables and see what I get. I can tell you that I have the pressure gauge on it and the numbers looked a lot better based on the little bit I did today.

[critter]

Just so you know I've not abandoned the project. boo-yah
I decided to work on some other stuff related to the swap and get back to the actual transmission a bit later.

[130fe]

Gauges look good, what kind are they?

[critter]

Speedhut.

[JeffT]

Nice looking gauges.

[joejaze]

Just so you know I've not abandoned the project. boo-yah
I decided to work on some other stuff related to the swap and get back to the actual transmission a bit later.

This setup looks sweet!

[critter]

I'm going to have to put some kind of resistor in to lower the brightness a bit. I wanted to keep my stock gauges everywhere else. These gauges came closest to matching what the factory put in while giving me features like recall on the tach and speedo, progressive shift light, etc.

[critter]

We finally got the club car show done this weekend so I'm back at it. Just wanted to let you, the viewing public know that I built another table where it should apply full line pressure at anything over 13 percent TPS. Sure enough, I was seeing 170-180 psi in drive when I did that. I had the car on jack stands. I still haven't driven it. I'm thinking I'll drop in the last profile that was showing 140 psi at 2000 RPM and take a quick jaunt soon.

[aronhk_md]

Hey Chris.....waiting as patiently as I can to hear the results...lol. Thanks for sharing the info by phone.

Aron

[Steve Chryssos]

Me too. Give me a call when you can.
/S