Jmod

I don't know if this helps, but i bought a tranny service kit that included a J modded plate from a guy on tccoa. Was around 120 bux and included a J modded plate to my specs, plate gaskets, new type 1-2 accumulator and blue spring, new type 2-3 accumulator and new style filter (for use with newer style pan that has a 'pocket')

If interested pm me and i'll give you the details.
 
J mod

The J mod is a great and simple trans mod that only involves drilling out some holes in the separator plate, if you looking for tire ripping neck snapping shifts its not for you, it will reduce shift time and slip making for a quick firm non violent shift.
Baumann kits allow for torque correction allowing the trans to respond to engine torque. I have a 97LSC with a 75rw valve body and a stage 4 Baumann kit and a 3K stall, and custom calibration for shift points and lock up, it shift firm and gentle with light throttle, but will set the car sideways at full throttle 1 to 2 shift.
Karl Baumann is a great person to deal with and his people will help anyway they can just give them a call.
 
Tiltedhalo said:
The J mod is a great and simple trans mod that only involves drilling out some holes in the separator plate, if you looking for tire ripping neck snapping shifts its not for you, it will reduce shift time and slip making for a quick firm non violent shift.
Click to expand...

I have to firmly disagree with you here. My 98 MarkVIII is bone stock except for the j-mod, and it will get sideways at 60mph if I wind out 1st gear. In addition to drilling the holes, if you want the jmod to shift hard, you need to remove the bottom 1-2 accumulator spring, and the 2-3 spring. In my car, at light-part throttle, the shifts are quick and firm enough that you know it just happened. Anything above 2/3s throttle, and it is definitely neck-snapping, and like I said, if I wind out 1st, it not only chirps the tires but gets sideways. This is still with the stock converter, and the stock 3.27 rear.
 
Ah, but you removed the springs, that will dump full fluid pressure, but thats more then the J mod.
 
I have the J mod drilled to 300 - 450 setting and the 1-2 shift is pretty hard - a little too much for me. I have the new accumulators and opted to leave the springs in.
 
Tiltedhalo said:
Ah, but you removed the springs, that will dump full fluid pressure, but thats more then the J mod.
Click to expand...

No it isn't, its part of the j-mod. If you read the article on tccoa, in the little grid for the different levels, it shows for the lowest level to leave the 1-2 alone and ditch the 2-3 spring, and for higher levels it says to ditch the bottom 1-2 spring, and the 2-3 spring. I did mine to the highest level, having previously done both the lowest and middle level j-mods on other cars, and thinking it didn't shift hard enough.
 
doing the j-mod stuff yourself must be MUCH easier than it sounds. im fairly mechanically inclined and reading about whats involved sounded like more than i wanted to attempt
 
No, its easy. Drop the pan, drop the valve body, remove plate, drill holes, remove accumulator springs, and put everything back together. Just take your time when you do it to make sure you don't drill the wrong holes to the wrong sizes.
 
Mill1978 said:
Im trying to get nice firm shifts and i want her to respond like she was meant too.
Click to expand...

The Jmod was created by the guy that initially helped design the 4r70w
If your looking for something to make the trans perform "as it's was mean to"

then you really want to do the Jmod and say "no" to aftermarket shift kits and controllers.
 
XLRVIII said:
The Jmod was created by the guy that initially helped design the 4r70w
If your looking for something to make the trans perform "as it's was mean to"

then you really want to do the Jmod and say "no" to aftermarket shift kits and controllers.
Click to expand...

Baumann was also an ENGINEER for the trans. not only one person design a tranny
 
Blenderhead said:
No it isn't, its part of the j-mod. If you read the article on tccoa, in the little grid for the different levels, it shows for the lowest level to leave the 1-2 alone and ditch the 2-3 spring, and for higher levels it says to ditch the bottom 1-2 spring, and the 2-3 spring. I did mine to the highest level, having previously done both the lowest and middle level j-mods on other cars, and thinking it didn't shift hard enough.
Click to expand...

we did the highest level off of the tccoa plans with the pre drilled plate on the thundermark and the 1-2 shift is intense! :burnout:
 
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