"Jmod" figuring out it all went well based on? - TCCoA Forums
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post #1 of 4 (permalink) Old 03-01-2018, 06:19 PM Thread Starter
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"Jmod" figuring out it all went well based on?

So you perform the jmod on a stock 4.6 .
Looks simple as long as you can closely follow instructions in which I have no issue doing this.
My question is how does the average person know all went well "the drilling" and know by looking at the rpm gauge and shift points and assume the mod went well Can people tell the shift points change dramatically on the rpm gauge and what would they normally be from 1-2 shift or 2-3 shift compared to stock shift range from a non "jmod" 4r70 trans
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post #2 of 4 (permalink) Old 03-01-2018, 06:35 PM
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The jmod is to affect the shift firmness, not the shift points. The shift points will change very slightly from a jmod, but they will be moved down, not up, and this is just a side effect of the larger holes in the separator plate filling the accumulators faster. But yes, there is a very noticeable difference in the feel of the trans after the jmod.
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post #3 of 4 (permalink) Old 03-01-2018, 06:40 PM
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O you will feel the diff..it shifts sooo much more crisp.more like a sports car not a cruiser .
Also if you messed it up you will know,lol..
You can always buy a predrilled plate as a kit with everything you would need. Better to be safe imo
Btw, where in MI are you located and found the car if you don't mind me asking. I live in the U.P rite now.
You need a tuner foir shift points. Either a custom tune or one like mine, mine adjusts not only shift points but firmness.
My tuner makes it feel like a mild Jmod with abit longer shifts and with a Jmod it makes it shift so fast and firm it's almost uncomfortable, but it can be tuned down if you wanted.
With the tuner set at max for firmness and length I get a 2nd gear chirp,.more off the line grunt and at wot it shifts at about 6200 rpms and reline is 6000 stock it was at 5800

Last edited by 94badbird; 03-01-2018 at 06:49 PM.
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post #4 of 4 (permalink) Old 03-01-2018, 07:49 PM
No, Mr. Lemmywinks, No!!!

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If you want to change shift points on our cars, you have to do it in the tune.

I spent more time on shift points than anything else; there's a lot of variables.

If you want to do that, you need the PRP setup; you won't be able to afford that many tunes, lol.

I don't drill plates these days, They make a version of this for all years: (This is for 00+)


That has all the mods already.

Replace the 1-2 piston, and any broken springs. Purple and blue seem to be popular.

Replace the 2-3 piston. the rubber will be hard.

Check the bore for the od piston, you may need the sonnax fix for the bore.

My car gears up and down like a manual.
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