Anyone have a 4L80E program?

[Telco]

I've run the new program, same issue. I called the builder, who advised that the transmission was built to have a firmer shift with the stock program, and recommended dropping trans pressure in the program by 10 percent. I don't want to screw this up, so what fields would I use to drop pressure? I'm thinking that I would want to drop pressure on the base pressure map. Thanks.

[joecar]

Yes, the base shift pressure tables, D0701, D0702, D0703.

[Telco]

Excellent, thanks. As soon as I get my laptop operational again, I'll give this a shot and report back either way. Slowly but surely we're getting there.

[6t7gto]

Hello,
i don't mean to hijack this thread but could someone point us in the right direction for programming a TCM from a diesel 4l80e so we could but it behind a gas 350 sbc.
thanks,
david

[Taz]

Hello 6t7gto,

Sounds like an interesting mix and match of parts. What year / vehicle is the 4L80 from ? Is the "gas 350 sbc" a fuel injected Vortec variant, an LS1, or a Gen I with a carb ?

If the engine you're using is a fuel injected Vortec or LS1 - then an LS1-B style PCM would be the most simple / easy controller to use. It would control both the engine and the transmission.

From a "hard parts" perspective - the torque convertor in the 4L80 may have a lower stall speed than is optimal - given that it came from a diesel application.


Regards,
Taz

[6t7gto]

Hi Taz,
thanks for the reply.
we are putting it in a 75 corvette which has no computer whatsoever.
the motor is the original 75 350 carburated.
we were told a diesel TCM is a standalone controller but it would need to be reprogrammed.
Having trouble finding someone to do that.
we know there are aftermarket controllers but not inexpensive.
I have read about TCM's from the boneyards going for $25.00.
But we need it programmed.

p.s.
we got the motor(TBI) and 4l80e as a package. early 90's pickup truck.
we have the whole harness and computer (16147060)

david

[Taz]

Hello David,

OK … I think I understand now. The project vehicle is a 1975 Corvette with the original carbureted Gen I 5.7 L. The 4L80E transmission and wiring harness is from a 1991 to 1995 TBI (gasoline) truck.

Regarding your diesel controller question ….. historically some companies (e.g. Art Carr) used a stock diesel truck transmission computer with a “custom chip” and wiring harness - for stand alone operation of the 4L80E. The down side to this technology was that these were not easily programmable - as a “new” chip had to be burned each time the tune was modified.

These types of controllers are still available, and are $350 plus - for the computer and custom chip (without the harness).

These early TBI controllers did not have a “flash” style memory (they used a chip) and therefore cannot be tuned / modified via EFILive software.

Fast forward a decade … the controller and harness from COMPUSHIFT is fully programmable - but well over $1000.

The good news is that the 4L80E transmission from 1991 (first introduced) through to 2004 remained virtually unchanged.

You could try building your own stand alone controller using your existing wiring harness and an LS1-B style PCM. The PCM would require MAP, TPS (sensor available for Holley carbs), VSS, and RPM input - to effectively control the transmission. Obviously, you would have to disable most of the engine related functions and DTCs - when constructing the custom tune.

The upside to this approach is that the controller (PCM) would be easily tuneable / customizable via EFILive software. Additionally, to operate a cable driven speedometer, a modified tail stock housing would be required.


Regards,
Taz

[6t7gto]

Good morning Taz,
Well, we have ONE of those problems addressed...I have an electonic speedometer from another project that I am planning to use.
Who/where would we get the remainder of the parts?
david

[Taz]

Hello David,

Where this project leads you, is up to you. Below are three possible options, including part numbers (where available), and possible retailers - intended as a reference only, not an endorsement of any company.

Option 1 - reuse your existing harness, and purchase a compatible controller and a custom chip

• Street & Performance - computer service # 16196395 or 16197327
• Street & Performance - custom computer chip

Option 2 - purchase a programmable controller and compatible harness

• GMPP controller and harness kit – part # 19212657
• TCI controller (part #377500) & TCI wiring harness (part #377502)
• Compushift (Hughes Performance) controller and wiring harness – part # 25-100

Option 3 – design & build your own controller system – reusing your existing harness

• LS1-B style 512Kb PCM (service # 09354896 for 1999 & 2000, service # 12200411 for 2001 & 2002)
• PCM wire terminals (may or may not be required) - Delphi Micro-Pack 100W (available from EFI Connection - part # 100-00176 or 100-00177)
• stock tune from a 2001 or 2002 Express / Savana with a 5.7 L Vortec and 4L80E transmission
• EFILive software
• plenty of time and patience

Regards,
Taz

[Telco]

Update - My laptop is still crapped out, but good news! My wife's laptop just crapped out too! I swapped her hard drive and memory into my laptop, and between the two we now have one working computer! I keep all my programs backed up, so I've not lost anything. Barring any further distractions I'm going to try fiddling with the program tonight so I can get the shift pressures lowered.