Who are my J-mod people?

[IwantmyMMnow!]

So, been mulling over the idea of getting the J-mod done to my MM. I've read over several threads on here about it and I wanna get it done. I do have some questions that I would like to get opinions/answers on...

Who is closest to me that I can have this done?
Are there any "since you're having this done, go ahead and do this" pieces to consider....similar to having the rear diff rebuilt while getting 410s installed?
What parts do I need and who should I get them from?
Is there a gain in HP with this mod and approx how much?
What exactly does the J-mod do?

TIA...happy motoring! :burnout:

[Marauderman]

Give Marty a call in the morning at his shop. He or Jeff should be able to handle all your questions--plus they are about the closest that I would trust with my MM...

[tallpaul]

I haven't had the mod done yet. I was considering a shift kit from dirtydogperformance.com, before I ordered it I called Lidio at Alternative Auto because that's where I got my programmer from. He said that the tuner had already been programmed to firm up my shifts and it has, he said that me adding a shift kit to the car after this would create some problems and the tuner would have to be reprogrammed. He said to not waist my money on it so I decided against any kind of shift kit or j-mod.

[IwantmyMMnow!]

I haven't had the mod done yet. I was considering a shift kit from dirtydogperformance.com, before I ordered it I called Lidio at Alternative Auto because that's where I got my programmer from. He said that the tuner had already been programmed to firm up my shifts and it has, he said that me adding a shift kit to the car after this would create some problems and the tuner would have to be reprogrammed. He said to not waist my money on it so I decided against any kind of shift kit or j-mod.

Thanks Tallpaul...that reminds me I forgot to add that I have a tune on my car as well....410s/93 octane. Bought the tuner and loaded tunes from 03mmmonroe (Russ)...I think the tunes are from Zack, but not 100% certain. (I don't do a good job of remembering stuff unless I staple it to my sleeve...lol)

[breeze]

Yea I had the pressure turned all the way up on my tune. Backed it down so nothing will happen to tranny

[LANDY]

Any decent tech can do this mod if you provide instructions.

[justbob]

Doing a Jmod is stupid simple and is way better for the trans than simply jacking the line pressure. Keep the pressures up and bye bye pump seal amongst others.

So what do you want to know exactly? 2 gaskets at Ford for about $3.00, 2 drill bits, and nine quarts of fluid. Oh and extra paper weights after your finished. :)

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[IwantmyMMnow!]

So what do you want to know exactly?

Doing a Jmod is way better for the trans than simply jacking the line pressure.

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How does the Jmod make it easier on the trans? What does 'jacking up the line pressure' mean? Is the Jmod a mod that is much needed on a S/C car, but not so much on a NA car?

Thanks...

[justbob]

How does the Jmod make it easier on the trans? What does 'jacking up the line pressure' mean? Is the Jmod a mod that is much needed on a S/C car, but not so much on a NA car?

Thanks...

Think of it as a fixed mechanical way of increasing volume and applied to only the areas needed and decreasing the time it takes to shift by removal of the accumulator springs ( factory added to soften the shift to help the poor necks/backs of future owners) You would think hard shift equals bad, but that is how much faster certain areas are now getting cooled by fluid (so I understand, doesn't mean I am right)

The easy way to get almost the same feeling is raising the shift pressures in the tune only. This can have little effect on a healthy trans to premature part failures and leaks both internally and externally on weaker transmissions over time.

It is a must in my opinion on a S/C car and a very good way to extend the life of the trans on all others if driven even slightly hard.

This was also a mod created by the very guy behind the creation of this trans, that right there was enough for me.

Seriously though, besides VERY messy, this is a small scale project that most anyone can do with the help of the online directions found with an easy search. Don't like the outcome? You can simply reinstall the springs and replace the adaptor plate you drilled for $30.00 and add two more gaskets. Anything this cheap to reverse a mod makes it that much easier to jump right in.

I have another sceduled late next month. Maybe I will do a full writeup with lots of pictures for people like me :)

Maybe someone else can add some more info.

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[RF Overlord]

How does the Jmod make it easier on the trans? It isn't so much that it's "easier" on the transmission...it's that having quicker shifts means less slip, which equals less heat and less wear.
What does 'jacking up the line pressure' mean?Increasing the pressure from the pump, which pushes the clutches together harder...again, less slip although too much pressure will break things.
Is the Jmod a mod that is much needed on a S/C car, but not so much on a NA car?That's more or less correct, but just because it isn't as "needed" on an NA car doesn't mean there's no value in doing it. No matter what power level you're at, the J-mod will increase the longevity of your transmission, as well as making the car more fun to drive.

[IwantmyMMnow!]

Thanks for the input...

With the tune I have loaded, the shift points are pretty aggressive; definitely feel it, even under 'normal' acceleration from a stop; no pause at all, just 1-bam-2-bam-3-bam-4. Even get a chirp from 1 to 2 at what I would call halfway between normal and WOT. (You should see the s**t-eatin' grin I get on my face when that happens)

At WOT it's freakin' awesome....just launches the car when that next gear is hit!

If I got the Jmod done, would I have to tweak my tune?

Edit: Since I have an '03, that means I have the 4R70W, correct?

[justbob]

Thanks for the input...

With the tune I have loaded, the shift points are pretty aggressive; definitely feel it, even under 'normal' acceleration from a stop; no pause at all, just 1-bam-2-bam-3-bam-4. Even get a chirp from 1 to 2 at what I would call halfway between normal and WOT. (You should see the s**t-eatin' grin I get on my face when that happens)

At WOT it's freakin' awesome....just launches the car when that next gear is hit!

If I got the Jmod done, would I have to tweak my tune?

I didn't but will soon. This summer heat has me damn near breaking my teeth it shifts so hard, and that is baby toeing it.. Most tunes have the shift pressures for each gear change unlocked in your Xcal.

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[IwantmyMMnow!]

I didn't but will soon. This summer heat has me damn near breaking my teeth it shifts so hard, and that is baby toeing it.. Most tunes have the shift pressures for each gear change unlocked in your Xcal.

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I have an SCT tuner. I was curious if having an aggresive shift schedule loaded on a tune in addition to the Jmod would possibly make the shifts so hard it would make it not fun to drive around...especially since mine is a DD...

I just finished reading (well, half read, half scan) Jerry's write-up on transmissions, etc...very good, informative read.

[SC Cheesehead]

I have an SCT tuner. I was curious if having an aggresive shift schedule loaded on a tune in addition to the Jmod would possibly make the shifts so hard it would make it not fun to drive around...especially since mine is a DD...

I just finished reading (well, half read, half scan) Jerry's write-up on transmissions, etc...very good, informative read.

You can back the shift pressures down in your tune if you get the Jmod, 'cause, yeah, the shifts will be hard!

[RF Overlord]

...or you can put one of the accumulator springs back in.

And yes, you have a 4R70W.

[Rockettman]

What the....Lidio told me straight-out when he sold me the tune: "I'm sending you one that you don't have access to change anything". At the time it didn't matter; but ideas like the J-mod, make me wonder if I should have said something at the time. :(

[ctrlraven]

I highly recommend if you get the Jmod done to back your shift pressure down to 0% on all shifts and go from there. If you feel you need more then bump it up 5% at a time.

Before I installed my 3500 stall converter at WOT mine would chirp 1-2 and 2-3 shifts. As others have said adding the converter will soften the shifts up because it absorbs it a lot which it did. Once I had the Jmod done I backed my shift pressure down to 0 and right now I am at 10% for the 1-2, 10% for the 2-3 and 5% for the 3-4 shift. It's nice and firm at light to part throttle, 70% to 90% it will bark the tires and at WOT it will chirp the tires and spin them during the 1-2 shift.

Watch the speedometer at the 1-2 shift, it was shifting at about 6000-6000 rpms and my redline is set at 6600. I wasn't fully WOT.
http://www.youtube.com/watch?v=1-jw3jvbcRI
1-jw3jvbcRI

[Rockettman]

I have another sceduled late next month. Maybe I will do a full writeup with lots of pictures for people like me :)

Yes please :)

[cj7chris]

This seems like a decent set of notes: http://www.crownvic.net/tech/4R70Wnotes.pdf

[justbob]

What the....Lidio told me straight-out when he sold me the tune: "I'm sending you one that you don't have access to change anything". At the time it didn't matter; but ideas like the J-mod, make me wonder if I should have said something at the time. :(

That is exactly when I tell the tuner he can keep his tune... No adjustability for a simple thing like a shift? NEXT. Plenty of others out there.

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[guspech750]

What the....Lidio told me straight-out when he sold me the tune: "I'm sending you one that you don't have access to change anything". At the time it didn't matter; but ideas like the J-mod, make me wonder if I should have said something at the time. :(

I would have told him to pound sand and went else where.


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Eaton Swap + 4.10's = Wreeeeeeeeeedom!!

[vegasmarauder]

The J-Mod is probably the single mod you can do that returns big on a small investment. I have been doing them in MM and CV's since 2001. The two highest mileage cars I know about are the wifes 197,000 and a '98 CV with 185,000 on the trannys. Wife's will STILL bark the tires on a WOT 1-2 shift. No burned discolored fluid anymore either.

I did this mod on a CV with 60,000 miles and a tranny with a failing OD band. I didn't think it would last, but it is going on 3 years and 20,000 more miles and while it is sloppy, it still hits OD fine enough for an everyday car.

I love this mod the best of all the quick mods.

[IwantmyMMnow!]

Tomorrow or Friday, I'm planning on going by the shop that installed my 410s to see if they can do the Jmod. Which set of instructions out of all the versions that are floating around would be the best to bring with me? Also, would it be better to buy a seporator plate to use versus drilling into the one that's on the car?

I've also noticed in several other threads the mention of the OD band going FUBAR around 60K...mine has 92K and I know the OD band hasn't been replaced...how can I tell if it's starting to go?

TIA...

[vegasmarauder]

When I checked with Ford you couldn't buy the seperator plate by itself, you had to buy the whole valve body (maybe that has changed). As far as the instructions go, they are all pretty much the same, some have some steps in a different order.

For a car that has not had the line pressure upped via a tune, the .110 holes are more than fine. The 1-2 will be very firm, and the others very good. Also do the reverse hole mod for faster reverse engagement, you will be glas you did.

The OD band is failing when it goes to shift into overdrive and the engine spins up slightly before the band fully holds. The RPMs will go up at the shift point and then come down about 200-300 RPM as the band engages. By the way, what this is doing is causing so much heat it cooks the rest of the friction material, fluid, and internal seals. When the OD shift starts, you can back off the throttle and let the band engage and then re-apply the throttle. This may buy you a few more months, even years before the trans dies, but no guarantee.

When it fully fails, the OD light will flash repeatedly and/or check engine light will come on. You will know when it is gone, the car will seem to shift into neutral when it goes to make the OD shift.

My friend just turned 175K on his '97 Towncar and he finally started getting the spinup on the OD shift, so there is no real set mileage the band fails at. I can tell you this, the wife's MM has 200K on it and we did the J-mod at 10K miles. It still shifts firmly in and out of OD, and she kicks it in the rear quite a few times.. That alone has sold me on the J-mod..

[IwantmyMMnow!]

So, I stopped by the shop that installed my 410s earlier this week and showed the mechanic the instructions for the J-mod. When he got to the part about removing the valve body, he handed me back the instructions and said he wouldn't touch it. He said he's not comfortable/familiar with working on ATs, particularly when it involves removing the valve body.

While I appreciate his honesty, now I'm back to square one on getting the J-mod done. I don't feel comfortable bringing my car to an arbitrary mechanic in town to have this done. I know there are a few guys on this website that can perform this mod, but they are 10+ hours from me. Unless there's someone closer, I'll be going to Mo's sometime next month to have this done.

Also, several days ago I had something (what I consider) unusual happen. I was merging onto the interstate, O/D was off, went WOT and when I let off the gas and turned O/D back on (nearly simultaneously), the RPMs 'hung' at 3500-3700 for at least 3-4 seconds until I tapped the gas again; then it dropped down to 2400 (I was at 70mph). This has happened 2 or 3 times before, but not to this extent (the RPMs dropped on their own). Is this an indicator that my OD band is starting to fail? Also curious as to how much it costs to replace a broken/busted OD band? TIA...

[RF Overlord]

Unless there's someone closer, I'll be going to Mo's sometime next month to have this done.That's the ticket...Marty will treat you right.

[IwantmyMMnow!]

That's the ticket...Marty will treat you right.

Yeah...I'm thinking that's my best bet since I'll most likely be out that way next month for the Chattanooga breakfast dealio...

[Rockettman]

Ok so now here's MY next issue with trying the J-mod myself.

I haven't changed trans fluid since high school (horse and buggy times - long time ago :(); and wouldn't remember how to PROPERLY refill after putting the pan back on.

[RacerX]

Right in the hole where the dipstick goes. That's why the atf fill funnels are very long and slender. Get ready to take an ATF bath too. I welded a drain hole into my pan.

[Rockettman]

Right in the hole where the dipstick goes. That's why the atf fill funnels are very long and slender. Get ready to take an ATF bath too. I welded a drain hole into my pan.

The filler/dipstick pipe part I remember. Its the actual preceedure to not overfill that I can't remember at all.

That would be my next question to anybody in the know...can they direct me to a vendor with pans with drain plugs? (I seem to recall ones for an E-150 being the pan to use?)

[RacerX]

Gotcha. Just fill until it touches the tip of the stick, start the car, fill to the proper level, keep the brake on and go through the cars, recheck and add if necessary, take for drive, recheck. :beer:

[tbone]

Install a drain plug while you have the pan down. Then you can swap out 4-5 quarts of fluid every once in a while without mess and a full trans flush becomes less necessary.

[justbob]

Without disconnecting the cooler lines it takes exactly nine quarts. I always put in eight, run it through the gears, then top off with the last quart. Always nine without fail.


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[Rockettman]

Gotcha. Just fill until it touches the tip of the stick, start the car, fill to the proper level, keep the brake on and go through the cars, recheck and add if necessary, take for drive, recheck. :beer:

Thank you.


Install a drain plug while you have the pan down. Then you can swap out 4-5 quarts of fluid every once in a while without mess and a full trans flush becomes less necessary.

Gonna get one for sure (maybe from Rienhart)


Without disconnecting the cooler lines it takes exactly nine quarts. I always put in eight, run it through the gears, then top off with the last quart. Always nine without fail.

That's nine quarts for a simple pan removal and re-fill??

[justbob]

That's nine quarts for a simple pan removal and re-fill??
Five'ish for pan and filter. Nine for a Jmod. You were inquiring about a Jmod right??



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[Rockettman]

^^^ yes that's correct.

Please excuse my ignorance, but why are they be different amounts? (J-mod vs. pan and filter).

[RacerX]

When you pull the valve body (which is the key to the J-Mod), and it pours out of every crevice, you'll understand... :D

[Rockettman]

^^ oh right I forgot. The valve body.