01blzxtreme

iTrader: (9)

i had a 6.0 with a supposibly built tranny, but things went downhill, motor broke a piston, and replaced with 5.3 to get the 6.0 fixed, then the damm tranny gave out..
so i got a t56 from a friend and my mph is way off, going like 80mph it says im going 30mph, anyone know what to mess in the tune to get it right, my tuner hasnt heard much about this, and this tranny swap isnt as famous on trucks, so im posting here...
and for gears what would work better with the t56, i got 4.10's now and have to shift too fast through every gear when cruising,

Jeremy@RPMTransmissions

iTrader: (12)

The T56 has less teeth on the speedo reluctor than the 4L60e. This causes the speedo to read way low. I'm no tuner so I don't know what exactly he needs to do to fix it. But on my old LT1 car we had to start over with a manual transmission file when I did my T56 swap to get the speedo to read right.

themealonwheels

iTrader: (20)

Dakota Digital SGI-5 universal speedo signal interface, $95. I installed it when I installed my T56 magnum and the speed read 2/3 of what the actual speed was. Installed the interface in an hour, spent an hour fine tuning the settings, and now I can manually adjust my speedo reading if I ever change gears, tires, etc.

01blzxtreme

iTrader: (9)

http://www.summitracing.com/parts/DAK-SGI-5/?rtype=10
so how do you calibrate it with one of those..

themealonwheels

iTrader: (20)

There are 4 switches and 2 adjustment buttons. There's a fairly extensive instruction set with the module to determine what combination of switches need to be used. Basically, set your mode (I think mine was on signal mode 6? It was fairly intuitive...), then take it for a short drive to see how far you are off. There's a table at the back of the instructions that tells you what each combination of crude and fine settings corresponds to for a signal multiplier. You can either estimate how much you're off with GPS, do the math and adjust the settings, or just determine if your reading needs to increase or decrease and try to adjust accordingly. I didn't see the table at the back and did my calibration with the blunt force method, took me about an hour with roughly 10 adjustments. My speedo is now dead-on and I have two settings: one for 225/60r16 and one for 275/40r18 rear wheels. It's easy and reliable, I've had it in operation for nearly 1000 miles/4 months now with absolutely no issues.