2002 Grand Cherokee 4.7 TCM Ordered!
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Joined: Jun 2005
Posts: 14,228
Likes: 19
From: Riverton, UT
It is a true mod.
Remove the negative terminal of your battery (10mm wrench).
Turn your ignition key to START and hold it there for about 15 seconds.
Turn your ignition key to OFF and remove it.
Connect the negative terminal of your battery.
Start but do not hit the throttle. Idle for about 10/15 seconds then turn off.
Restart the truck and drive as usual. It will take at least 12 starts and 48 miles to fully retune the computer. Hard Codes leave a shaddow for 40 full cold starts.
Turn your ignition key to START and hold it there for about 15 seconds.
Turn your ignition key to OFF and remove it.
Connect the negative terminal of your battery.
Start but do not hit the throttle. Idle for about 10/15 seconds then turn off.
Restart the truck and drive as usual. It will take at least 12 starts and 48 miles to fully retune the computer. Hard Codes leave a shaddow for 40 full cold starts.
Thanks Hydra but I didn't need to reset.
I just plugged it in, re secured the TCM to the body, and drove off. As stated earlier, the RPMs dropped by about 300-400 RPM. I can now tach 2k at 75, and maybe 1600 at 65 with 3.55's and 31" tires. The downshift from the 2nd O/D to 3 takes a huge push on the throttle, but agan this is only necessary if you need immediate power. Slower acceleration needs only require a moderate throttle press. The 2nd O/D for me was at about 1600 and when I needed to jump up to get over a hill to maintain 65 it would jump to about 3k. My Overhead has been amazingly accurate so I don't bother hand calculating anymore but it was reading 18-20 MPG. Thats an easy 3-4 MPG increase for me. Like I stated earlier, if you're within the years of 2001-2002 with a 4.7, this WILL work.
I just plugged it in, re secured the TCM to the body, and drove off. As stated earlier, the RPMs dropped by about 300-400 RPM. I can now tach 2k at 75, and maybe 1600 at 65 with 3.55's and 31" tires. The downshift from the 2nd O/D to 3 takes a huge push on the throttle, but agan this is only necessary if you need immediate power. Slower acceleration needs only require a moderate throttle press. The 2nd O/D for me was at about 1600 and when I needed to jump up to get over a hill to maintain 65 it would jump to about 3k. My Overhead has been amazingly accurate so I don't bother hand calculating anymore but it was reading 18-20 MPG. Thats an easy 3-4 MPG increase for me. Like I stated earlier, if you're within the years of 2001-2002 with a 4.7, this WILL work.
This is nearly accurate, however, we still do have large hills in the area. The Loess Hills are over in Iowa where I am from, and those hills thin out to our side of Nebraska a little bit. But I can say this, the 2nd OD to 2nd or whatever is pretty annoying with the throttle required to get it going, but I think I can manage since there arent many hills.
