4L80E & TH400 Tech.

[softballnrd27]

Clinebarger-
I am currently looking for a decent 4l80e to build up and I can only find the 91-96 cores in the price range I am comfortable with. It will be behind a 5.3 and will eventually have a turbo or 2. My current th350 wont hold fluid and is slipping real bad so I need to replace it. Can I control the 91-96s with the 03 computer? Can I add an aftermarket floor shifter later on down the road? I plan to do everything you have listed, can you explain why? Just for my knowledge, not questioning you at all.

[clinebarger]

Originally Posted by softballnrd27

Clinebarger-
I am currently looking for a decent 4l80e to build up and I can only find the 91-96 cores in the price range I am comfortable with. It will be behind a 5.3 and will eventually have a turbo or 2. My current th350 wont hold fluid and is slipping real bad so I need to replace it. Can I control the 91-96s with the 03 computer?

A 91-93 can be modified to work with a '03 PCM. '94-'96 will work with no modifications.

I will cover the '91-'93 modification in detail because others might need this also....

'91-'93 models use a "Silver" Bosch EPC Solenoid that is not compatible with '94 & up PCM's, It was replaced with a "Black" EPC. It is an accepted method to just replace the EPC with a '94-'03 version, And most of the time it works fine, But in some cases it will cause line pressure issues, Besides if your rebuilding....Do it right from the Start!!!

Parts needed....
'94-'03 EPC solenoid
.093" drill bit
Trans-Go Separator Plate part# 48-PLT-01
IF your core has the original internal harness, You will need a '94-'03 Harness

First INDENTIFY your Valve Body! Parts get swapped all the time....
Notice the EPC is Black, This is a '01 Core.
Notice the Arrow pointing to a slot in the Valve Body, This is the EPC Vent. A '91-'93 will not be vented.







Once the Valve Body is removed, Flip it over, Remove the EPC, At the Arrow, Drill a .093" hole through too the other side, This will Vent the EPC with a hole instead of a machined slot.





I am including this for Information, '91-'93 will have a EPC hole in the Separator plate, This is no longer needed now that you Vented the Valve Body, The Trans Go plate does not have this hole, You have now completed your conversion to the Later/Better/Compatible EPC solenoid.
Picture of where the EPC hole is in the plate...

[clinebarger]

Originally Posted by softballnrd27

Can I add an aftermarket floor shifter later on down the road? I plan to do everything you have listed, can you explain why? Just for my knowledge, not questioning you at all.

Yes, You can add a Floor Shifter, However....With correct PCM Tuning, You do not need to manual shift this unit, Just remember to always Race/Burnout in D3 NOT D4/OD, Selecting D3 applies the Overruns & Protects the Overdrive Sprag from Shock/Damage.

I listed a lot of things that NOT EVERYONE will need, Do you have a max horsepower/torque goal? Slicks/drag radials?