JMod Drill Specs Question

Lux

Lux

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I've got a 97 LSC, sniper tuned for harder shifting. I'm doing the Jmod this week or next weekend. Figured it was time for a fluid change with 67K on the clock now. I have all the parts and a few questions.

Since i'm running a tuner and gears are next im curious as to what range i should drill my specs to? Eventually i would like to have a poweradder and i see on the TCCOA article the listing for 300-450 and recommends to leave the one springs out.

It already shifts firm with the tuner, should i leave the springs out or put the heavy duty ones i have already for it in there?

I also see some mention of 600 HP drill specs, should i use these or the 300-450 ones? Obviously im not making this power now or will be any time soon but im curious to know if i use the specs i use the specs i wish the car will have one day, now, while im in there?

Sorry for the newbish questions...i just dont feel like doing the work twice or screwing anything up as this is my daily driver. Thanks for any help
 
Lux said:
I've got a 97 LSC, sniper tuned for harder shifting. I'm doing the Jmod this week or next weekend. Figured it was time for a fluid change with 67K on the clock now. I have all the parts and a few questions.

Since i'm running a tuner and gears are next im curious as to what range i should drill my specs to? Eventually i would like to have a poweradder and i see on the TCCOA article the listing for 300-450 and recommends to leave the one springs out.

It already shifts hard with the tuner, should i leave the springs out or put the heavy duty ones i have already for it in there?

I also see some mention of 600 HP drill specs, should i use these or the 300-450 ones? Obviously im not making this power now or will be any time soon but im curious to know if i use the specs i use the specs i wish the car will have one day, now, while im in there?

Sorry for the newbish questions...i just dont feel like doing the work twice or screwing anything up as this is my daily driver. Thanks for any help
Click to expand...


I have heard of others leaving the springs out and they hated it. It beats the hell out of the tranny every time it hits 2nd gear. Just telling what I have read.

The Jmod will firm the shifts up even more once it's completed. I would leave the springs in.
 
If you have the line pressure increased via the computer, don't touch the seperator plate. Only do the j-mod, if you retune the vehicle and remove that portion.
 
Psychostang said:
If you have the line pressure increased via the computer, don't touch the seperator plate. Only do the j-mod, if you retune the vehicle and remove that portion.
Click to expand...

Isnt drilling the seperator plate the JMOD procedure, just the accumulators are the upgrades, right?

and that is something i was wondering. I'm definitely going to do the JMOD. I'm curious as to people who've done it and have a tuner on thier car set thier shifts at. I dont want to damage the tranny, only have it shift nice and crisp, while prolonging the life of it.
 
nolimit94VIII said:
I have heard of others leaving the springs out and they hated it. It beats the hell out of the tranny every time it hits 2nd gear. Just telling what I have read.

The Jmod will firm the shifts up even more once it's completed. I would leave the springs in.
Click to expand...

Good info, thank you. I dont need to beat the nuts off the tranny but want a SOLID shift. I remember before the tuner when it shifted slow and lazy...dont miss that at all. I've went conservative on the option, i was waiting until i did this.
 
nolimit94VIII said:
Yes, the springs are purple and blue and then the new piston and the separator plate is what gets drilled.
Click to expand...

Nice, i think i have both of them and a brown one for some reason :confused:

I know i ordered an extra by mistake.

I'll check out that site, thx
 
Yes, the jmod is drilling the seperator plate. I would leave all of the springs in, and then use the second set of drill specs, instead of the base set. This should get you what you want. But, as I said before don't touch it until you remove the program that increases line pressure via computer. Otherwise you will damage the trans or make the car undriveable. The latter due to the rear end breaking loose everytime the trans shifts. Especially during wet road conditions.
 
When I did my jmod I put both springs in 1-2 accum and left out the spring for 2-3 accum. I am basically stock so I used the low HP specs. I get a nice chirp into 2nd with my foot in it and a nice snap into 3rd. I like it :).

The jmod opens the intake/exhaust ports for the accumulators. Gets fluid in/out quicker for the firm shifts.
 
I'd go with the 300-450 drill specs, leaving out the 2-3 spring. I left the bottom spring out of the 1-2 accumulator; the upshift is noticeably harder but it isn't that bad.

If you go with the 600 hp drill specs when your engine doesn't make nearly 600 horsepower, your upshifts will be harsh. I wouldn't.
 
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