'88 1 ton TH400 to 4L80E swap.

['88C3500]

Hello All,

New here. My '88 3500 has an elec speedo. Anyone know if the 4L80 E will signal my speedo correctly? How are gear ratio changed dealt with with the e speedo?

Thanks.
Dave

 

[Supercharged111]

Speaking from my 4L60 to 4L80 swap yes, I believe it should plug right in. However you will need to add the input speed sensor. How will you be controlling this? I'm assuming it's TBI and you'll swap the harness and controller right in? As far as the speed goes, that year range should have a DRAC module. IIRC you change up some jumpers inside to set the speedo for gears, tires, etc.

 

['88C3500]

Howdy,

I'll show how dumb I am on late model stuff. I just bought the '88, which is all stock. I ASsumed that since it's TH400 has an electronic speedo output, I could make the speedo function from the 4L80E. I will search the subjects of input sensor and DRAC module to see if I can learn something about those.

As far as controlling the 80E, you can do a full manual for $200ish, or a nice full auto controller for $500 ish. I have read that you can use a separate computer from a 4L80E equipped diesel truck, but I don't know the details.

Thanks.
Dave