Automatic Mach 1 transmission in 04 GT?
11-26-2013, 10:54 PM
#1
Thread Starter
Join Date: Nov 2013
Location: Georgia
Posts: 3
Automatic Mach 1 transmission in 04 GT?
A friend of mine has a built 4r70 and 3200 stall out of an 03 Mach he will be selling soon and I was wondering if any of you guys might know wether or not i would have any trouble replacing my stock 4r75 with his 4r70. Just wondering if the transmission pins and everything will line up the same. Thanks!
11-27-2013, 10:12 AM
#2
1st Gear Member
Join Date: Oct 2008
Location: Oklahoma
Posts: 58
Tranny swap
Everything should bolt up and all the harnesses should plug in. Your problem will be in the tune of the ECU/PCM of your 04GT to correct the OSS reading.
The 4R75W uses a 24 tooth gear internally for the OSS (output speed sensor).
The 4R70W uses a 6 tooth gear internally for the OSS (output speed sensor).
The ECU setting must be changed to read the 6 tooth gear or your speedo will be way off and the car will shift weird and run like crap.
I know because I went the other way with my 02GT and put a Mach 1 4R75W in it. Had my tuner guy reset my tune for a 24 tooth OSS and everything was fine....
The 4R75W uses a 24 tooth gear internally for the OSS (output speed sensor).
The 4R70W uses a 6 tooth gear internally for the OSS (output speed sensor).
The ECU setting must be changed to read the 6 tooth gear or your speedo will be way off and the car will shift weird and run like crap.
I know because I went the other way with my 02GT and put a Mach 1 4R75W in it. Had my tuner guy reset my tune for a 24 tooth OSS and everything was fine....
Last edited by TheDarkKnight; 11-27-2013 at 10:26 AM.
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