J Mod Questions (scroll down to bottom plz)

Jrgunn5150 · Jun 17, 2008

Hole 8 is for the direct clutch. If you open it, it will apply quicker and slightly more forcefully. if you don't, it won't, it's not like a make or break hole. For a bolt on car like your's, it won't make a difference either way, in reallity. I wouldn't open it for you, and you wouldn't know I didn't lol.

Wes8398 · Jun 17, 2008

J.R. said:
I wouldn't open it for you, and you wouldn't know I didn't lol.

HAHAHAHA!

Is the direct clutch the "lock-up" part of it? Why would Jerry state that post-96 cars didn't need that hole done?

Jrgunn5150 · Jun 17, 2008

Lol, i don't mean it like a scam, I just mean, you don't need it, i try not to add unneeded pressure.

The direct clutch pack, also called the forward clutch pack, are the 5 clutchs and steels that make you go forward. 4r70w's are a little odd inside, and they are not synchronized, so the clutch pack applies, disengages, it double clutches for you, then reapplies. (oversimplified version, but you get the picture)

A "true" 4r70w, as in, not an AODE or early ball sucking 4r70w, engage the direct clutch quicker through different means, therefore, there is no need to open the hole for a mild build.

Wes8398 · Jun 18, 2008

Makes sense .... thanks again for all your time!

nyuk98gt · Jun 19, 2008

Wes8398 said:
Thanks Chris and JR. I've got this little voice in the back of my head telling me NOT to do this. I'm not sure why, but I'm feeling very leery about it for some reason. The guy that's going to do it for me is a transmission specialist, so I have no worries there - but I just feel like something's gonna get messed up. I think it's cause of all the reading up I'm doing on the mod. I'm reading some people's likes and dislikes, then reading others that are totally contrary. Some people have done the mod one way, some have done it another. Some just open the holes and don't do any springs/accumulators; some do all of it. Some suggest NOT to do the hole for the reverse shift, some say it's fine. Some people are telling me to open hole #8, some people (including Jerry's article) are telling me not to. lol All I wanted to do was make sure I was getting things right, but now I'm doubting the mod all together. lol

Regardless, thanks for your help guys.

Wes8398:

I will tell you what I would do if I were you....

DO THE J-MOD!! It will make the shifts quicker so there is less friction/heat build-up in the fluid and the clutch packs will last longer. Add a cooler, too, even if you don't do the J-mod (tut-tut-tut if you don't) because it will remove some heat and this is a good thing.

Update the accumulator pistons. The older models get stuck in the bores and then the transmission won't shift properly.

Update the 1-2 springs and put both in. If you leave out the bottom one, the 1-2 shift is going to be pretty hard and you might not like it for tooling around town.

Don't bother with the reverse hole.

If you go with 300 hp/mild hole sizes, then the trans will shift almost stock at light throttle and very quick at full throttle. This is a good thing: no teeth jarring shifts when puttering through the grocery store parking lot! I think some people go for bigger holes and this makes for pretty harsh shifts even at light/moderate throttle and this is the reason they complain. Don't overdo it, as Mr. Wroblewski warns in his 'book'.

Your shop guy can do this for you. It isn't hard and he has all the right tools (inch-pound torque wrench, a lift, snap-ring pliers, etc.) and he has been into transmissions before. This is the first auto I've owned and I was pretty anxious about doing the work but it turned out to be not such a big deal and quite enjoyable. Things seem easier once you do them, lol!

Think about it some more and I hope you "git 'er done".

Chris

Wes8398 · Jun 19, 2008

Thanks for the words of encouragement Chris. You convinced me and I ordered all the required parts from Randy Stinchcomb today. My transmission buddy is going to do the job, but I'm going to lend a hand just so I can learn a bit from the whole process. Lookin' forward to it, but it's gonna be a few weeks before he's freed up to get my car on the hoist. Lookin' forward to it, and thanks everyone for your help.

nyuk98gt · Jun 20, 2008

Wes8398:

Lol, I'm a J-mod cheerleader!! :dancing6: You will really like it and it's good for your transmission. While you're waiting, read and re-read Jerry W's articles and A-Train's articles (until you have them almost memorized). Also, you need to buy drill bits but they are "tap and die" (numbered) bits, not just something you can find at Lowe's or Home Depot (no flame intended towards those businesses). Other than the bits and the valve body parts and gaskets and ATF (Mercon V) and a couple of cans of brake cleaner (keep it far away from your paint!!), you should be ready to go.

Post back with an update please, Wes!

Chris

Wes8398 · Mar 20, 2009

Hole 5??

I'm raising this from the dead because I'm FINALLY going to do the J-Mod. I have one last question. In the "modifying the main control" section (chapter 13), under the "2-3/3-2 shifts" section, referring to hole 5 Jerry says "if you do not have the higher load 2-3 capacity modulator spring, you cannot make this hole bigger than .081. You need a 98 or newer main control". I've done a gear change which this section says I would want to open hole 5 to .100 but I have a 97 trans ... just leave it at .081? I'm assuming that a "modulator spring" and an "accumulator spring" are 2 different parts, right? Since Jerry advises to remove the 2-3 accumulator spring, it would make sense that he's referring to a different part.
Also, If I have to leave #5 at .081 does that mean I also have to leave #4 at .081? Or can #4 be opened to .100?
Thanks in advance!!