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Did you damage your 4R70W by performing J-Mod?

  • Yes

    Votes: 6 7.4%
  • No

    Votes: 72 88.9%
  • Yes, but I fixed it easily/cheaply/quickly

    Votes: 3 3.7%

  • Total voters
    81
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Discussion Starter #1
How many people have performed the J-Mod to the transmission and had a problem that was a result of the mod, or your own handi-work while performing it.

I'm looking into performing this and it scares the bejebus out of me. I'm sure that I can do it but I gotta get up the nerve to do so, not to mention the inch-lb torque wrench and parts.

Thanks,
Willum
 

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I didn't damage it, but it sure as hell didn't shift into drive after we bolted it back up. The gear selector didn't shift into drive, (luckily I could get out of the driveway in reverse, then back into it again in reverse.) The rod that slides in the VB was sticking and we had to tweak it back so it could slide freely.

What I did was make a folder on my laptop with every bit of info I could gather. I studied it for about a week. Just have the printouts or files handy, just in case. It's really simple once you get in their, I could do it all over again with no documents.

Get the Jmod article off tccoa, check mn12performance.com for all their trans info, and use the search here, you'll have all the info you ever need.
 

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I didn't have any problems at all, just go slow and read the article about 10 times before you start, and then another 10 while you are doing it
 

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Trumpeter Extraordinaire
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I'm not technically-oriented when it comes to cars, so I spent about a year deliberating whether or not to do it. When my car-repair-savvy brother visited in August, I asked him if he thought he could do it. He leafed through the article, and after 10 minutes, he said "Let's get to it!"

It helps to have a helper who knows what to look for. I was amazed at how smoothly everything went, and equally surprised that it took less than 4 hours. No problems encountered.....an a big thanks to my brother!

Just like Rich95XR7 states: read the article several times, and keep it handy while you do the work.
 

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No problems at all, but I REALLY took my time, since I was doing it by myself and this was my first time in an automatic transmission. I even did the reverse and OD servos, which seem to cause the most problems for people. Read the directions as many times as it takes, start early in the day (in case you need to make a parts run), and don't get in a hurry.

Marcus
 

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I've done 4 of these things already, my last one took 2 hours I think ... LOL. If you're a first-timer, I'd say skip the OD and reverse servos - they're optional anyway. Take your time, read the directions and Don't rush! Rushing is how you make mistakes. Trust me. I've messed up putting the OD servo back in just like so many others have. Not that it's a big deal, but you don't want to have to drop the pan again.
 

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I feel like I'm going to confession here...

My failure is not related to the mod itself, just my own stupidity.

I decided to do mine at 107,000 miles. I had already done it on my 94 Mustang AOD-E 2 years ago, and was pleased with the results, so I was ready to kill the bird finally. I screwed mine up because I was stupid. I didn't put enough Mercon V in when I finished it, tried to test drive it, and fried the forward clutches due to lack of line pressure.

My mistake happened because I had recently done the converter and pan drain/refill, and I wasn't going to drain the converter again. Since I dropped the pan and valve body ONLY, I ASSUMED that I only needed about 5-6 quarts to refill it (didn't want to overfill). I also assumed it would need to cycle around a bit to fill all the passages in the valve body, and that was why the car wouldn't go into gear immediately. Suffice to say, I was wrong... Apparently, the valve body contains a check valve that keeps the converter from draining, and when I pulled the VB, I lost at least half of my converter fluid. I put about 2 miles on it, with it about 4 quarts low. I filled it to the top of the rang, put around 70 miles on it over the next 2 days, and then it lost forward gears when my wife was driving it (of course). She limped it home for 15 miles, not sure how.

Now I have a Dennis Reinhart tranny in mine. I'm very happy, to say the least...

But with labor for the install ($585), new radiator ($160) and B&M cooler ($60), and $1600 to Dennis, it was a costly mistake. So much for my tax return and the tiny profit I made from selling my house...

Again, my failure is not related to the mod itself, just my own stupidity.
 

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terraplane8 said:
I feel like I'm going to confession here...

My failure is not related to the mod itself, just my own stupidity.

I decided to do mine at 107,000 miles. I had already done it on my 94 Mustang AOD-E 2 years ago, and was pleased with the results, so I was ready to kill the bird finally. I screwed mine up because I was stupid. I didn't put enough Mercon V in when I finished it, tried to test drive it, and fried the forward clutches due to lack of line pressure.

My mistake happened because I had recently done the converter and pan drain/refill, and I wasn't going to drain the converter again. Since I dropped the pan and valve body ONLY, I ASSUMED that I only needed about 5-6 quarts to refill it (didn't want to overfill). I also assumed it would need to cycle around a bit to fill all the passages in the valve body, and that was why the car wouldn't go into gear immediately. Suffice to say, I was wrong... Apparently, the valve body contains a check valve that keeps the converter from draining, and when I pulled the VB, I lost at least half of my converter fluid. I put about 2 miles on it, with it about 4 quarts low. I filled it to the top of the rang, put around 70 miles on it over the next 2 days, and then it lost forward gears when my wife was driving it (of course). She limped it home for 15 miles, not sure how.

Again, my failure is not related to the mod itself, just my own stupidity.
Who would do something like that? :D
 

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Formerly Fdawg97LX
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my friend joe helped me do it. he did his own car before we did mine so he had some experience. it took us about 3 hours to do the jmod and install a cooler. we had all the neccessary tools and parts so we didnt have to make any runs to the store. everything went as smooth as possible.

Frank
 

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I figure I should say I wasn't making fun of you Terraplane8.
I did the exact same thing (costed about $300 less) to my 97' in the middle of last winter which is why I put the 'big grin'.




3 hours seems like it went very well. It def. took me a lot longer.
 

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Yes, AaronT, I remember you and I going in circles trying to figure ours out last Spring... Same symptoms for you, I believe(?).

Anyway, I finally got my DennisR tranny installed a month ago (I had a busy Summer with a lot of travel for work). I'm pretty happy with it, although I think I need a new tranny mount now. Shifts are way better than before, but it kinda clunks a bit going into second, and has some underbody vibrations when slowing down from hiway speeds; feels like a driveline/bushing-thing, maybe the 3rd member bushings or tranny mount are getting loose on me. Gonna check it over tomorrow when I change the oil.
 

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Did mine this past winter, while the tranny was in the car of course, and somehow got disorientated right before I pulled the 1-2 accumulator out. Ended up pulling out the OD servo bore, letting the band slip off, not realizing it. Took it out for a drive when I was done and no OD. Figured out that was my problem a day later and then the next day dropped everything out and put it back in. Worked fine ever since. And yeah, I read through the article about 10 times as well. I've helped do 2 others after mine and it never takes very long now. Oh, and that was my first time inside an automobile transmission.

Joe
 

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I just did mine too ... as others have mentioned ... i didnt drain the torque convertor also bc its a new one with about 1500 miles on it. BUT i made sure the fluid level was up and kept checking til i had enough in it.

All in all ... the two yrs i spent procrastinating is almost shameful... its alot simpler than you think.
 

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Don't feel bad willum...

I still am contimplating :D

I want to get my "I KNOW" I can do mods first.. Then to this "dreaded" (scary) mod. I will probably drill the holes for 300+ HP, seeing as I want MAX performance :D
 

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If I were you I would buy the PA VB shifts just as good as Jmod VB and is a better VB than stock and is less of a hassle to install than 99+. No Drilling, so know wondering if you did it right ore not, its also a manuel VB. My opinion is you cant beat it for the price and quality.
 

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I did my JMod last summer with help from Al Simanek. We went REAL slow and skipped the OD and Reverse servos since I've got a 97.

I'm now ready, except for lack of a torque wrench, to change fluid and filter. Yes, I've put 17,000 miles on the bird already!

My mod came out so well, I let other Bird/Cougar owners drive the car to experience the difference. Thomas was one of my victims, and now Thomas has instituted a JMod tour here in Iowa. 'Nuff said?
 

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I'm still contemplating my J-Mod excursion... By reading these articles here, though, it doesn't really seem like it's as bad as I thought it might be. I've never done *any* transmission work, but if I do perform this in the future, I'll have to take a trip to my dad's to have him help me out. He has a massive garage of tools and a decent amount of experience with cars... Not too sure about transmissions, though. Anyone in the northeast Ohio area wanna' come out and help a guy? :)
 

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It's pretty darn easy to do. Just a little messy. You just have to take your time and be careful, really not much to it. A lot of pics floating around here, as well as threads in case you run into trouble.
 

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Aaron_T said:
It's pretty darn easy to do. Just a little messy. You just have to take your time and be careful, really not much to it. A lot of pics floating around here, as well as threads in case you run into trouble.
Yeah, I'm just going to keep on reading posts and looking at pictures until I finally grow bigger balls and just do it someday. Actually, I think I might do it later in the summer. I'm doing all kinds of stuff to my 'Bird to try to give it the best performance without going too crazy with bolt-ons, etc...
 
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