4R75W swap?

[97MarkJA]

I found a 4R75W out of a 2003 mach 1 I might be able to pick up. Has 19k on it.
Other than the harness and electronics anyone know what else might be involved? I know I've seen a couple of cars on here with the swap.

 

[97MarkJA]

? Anyone

 

[Chris_Murder]

Tailshaft swap, all of your current solenoids and wiring, possibly your stock planetary ring gear depending on the year of the 4r70w/4r75w since they have no output shaft speed sensor teeth, and the planetary ring gear changed in 04 and cause the PCM to think it is going 400 x as fast as it should be. If your comfortable going that deep into it than do it. The 04+ 4r70w/4r75w received hardened planetary gears and a better sun gear as well. The stub shaft is also straight cut and appears to be hardened as well judging by the color.

 

[97MarkJA]

I've done a lot of research over the last couple of days and talked to Alan at dirty dog. Seems to be some debate over when they started the 75 03 vs 04, and if it is the 75 it will have the hardened parts coming out of a mach 1.
For the oss it can be changed in the sct software from a 6 to a 24 count if need be but if the gear isn't present for the vss the tail shaft housing and shaft will need replaced with the old unit. (You are correct)
Meaning a entire tear down.
So here is the question, tranny with 19k on it.. tear down and replace the tailshaft or buy a 98 tranny and rebuild the entire thing? 2003 tranny is $550. Rebuildable core is cheap.

 

[Chris_Murder]

I'm in the process of the same thing. I chose to start with a 16,000 mile 2004 transmission and changed the tailshaft and planetary ring gear since I was in there anyway and didn't want or need a retune.

I also chose to go wild with the build though adding additional frictions and steals, replacing all of the lip seals inside the drums, replaced the scarf cut factory direct drum sealing rings with solid ones, switched to an aftermarket 4 seal 2-3 accumulator, upgraded to the sonnax OD servo pin, upgraded to a high carbon OD band, upgraded to the sonnax pressure regulator valve, replaced the mlps, better torque converter, large transmission cooler, lpw deep transmission pan, all new seals, jmod, etc...

I don't want to have to replace it again for a long time and I wanted to do it right the first time.

Ultimately you'll have to make the choice on how far in your comfortable going and how much you want to replace/upgrade/leave stock for your application.