trans J-mod...who's done it?

Casey Weikert

Registered User
here's the deal. I have spent ton's of money on my 89,000 mile 1995 SC. Raised top, dual exhaust, new rear with 3.73's, MAF, cold air intake, 5% SC pulley, I think that's about it. I've beat this car like it owes me money at the dragstrip and my best to date is 14.60. Guys here in Iowa who have spent less and done less to their cars are faster. I think my weak link in my car is the tranny. Or maybe my expectations are unreal about how fast this car should be. I think I should be faster, like low 14's faster.
So for all you J-Mod people out there are you happy with it? I don't hardly ever drive the SC but I don't want to take it out on a Sunday and have the
1-2 shift snap my head back just taking off from a stoplight. A noticeable shift point is okay but not a WHAMMO BLAMMO shift.............maybe that's an unreal expectation too.
I am almost to the point of selling this car and getting to work on my Monte Carlo SS.
Thanks in advance guys..........Casey
Van Halen kicks A$$
 
what year is ur SS?

Well, about your J MOD, maybe it will help you, will bring in firmer shifts. I think what you need to invest in, is weight reduction.
 
SS is an 87 T-top. Nice car, had it since I was 16...now I am 26. Oh if that car could talk. The stories it would tell.
Weight reduction eh? Not so much. I don't want to sacrifice anything. Besides, the guys in SCCOIa haven't done that. Maybe my car is just a turd. Maybe I just can't drive. Maybe I need to stop thinking about it so much. I really think it's the tranny.
 
nice SS man, i have a 86 PONTIAC GRAND PRIX LE T-TOP, this car is so rare man, i havent found any body else with it, dont see it in the junkyards either. I had this car for 2 years now, its been in my family for 6 years. Its never let me down, the only time was when the timing chain broke off. But other than that, never, never i say. I am building a 350 Chevy Engine in my garage for it, So far i have the Block and the Racing Fully Adjustable Timing Chaing, and a HIGH PERFORMANCE RACING CAM, still need the rest, but that will be in the future. This car man, wow, good times in it, good times. I love my Pontiac.
 
am i right in assuming that a j-mod is something that is done as an alternative to a shift kit? or can it be done in conjunction with one?
 
Yes, the J Mod is the brainchild of one of the Ford engineers who designed the 4R70W tranny. And it is an alternative to a shift kit. I put a Trans Go shift kit in my '95 last summer, & I'm perfectly happy with it. There are 2 or 3 options as to the firmness of the 1-2 shift when you install the kit. I chose the hardest one, & I do now have pretty hard 1-2 shifts. Hindshight being 20-20, I most likely would've chosen the middle option when drilling the plate for the 1-2 shift! Also, I didn't know much about the J-Mod at the time. You can read all about it over on TCCoA.com. It looks like a good mod, & is cheaper to do than a shift kit.
 
I read the article about 4x and once you understand ehat hes talking about you can customize any part of the up shift or down shift or simply make it shift faster. This makes it better then any shift kit and you can do it cheap.
This is only for the 4r70w. I think all these cars hit a wall untill you cam change and get more air from the intake all the way to the heads. One mod in the system may help a little but its all or nothing with these cars.
 
So for all you J-Mod people out there are you happy with it?


I did the J mod on my 94 about three years ago and have no regrets at all. It was a fairly easy job but I read the J mod articles on TCCOA several times before doing it. I also installed 3.55:1 gears and a trac-lok differential and the only issue I had was the WOT 1-2, 2-3, shift points were between 3500-4000 rpm which is much lower than the factory 5000 rpm (or there a bouts). My times were slower at the track. To resolve this I had Jerry burn me a custom chip which, among a few other things, raised my WOT shift points back to 5000 rpm (or there a bouts). I’ve been happy with it every since.

I think I should be faster, like low 14's faster.

Installing a trac-lok differential would definitely help. Drag radials would definitely help. A long cool down would definitely help. Getting rid of all dead weight would help. Underdrive pulleys would definitely help.
Also I noticed on your member’s page your using a C&L 73mm MAF. I had the same meter on my 95. I switched to 75mm Pro-M bullet and noticed a definite S.O.T.P gain in power, especially down low. Now I have a Pro-M on my 94 also. :D
 
Actually I have a posi unit. Brand new tires. Traction is no problem at all. Hardly even chirps them off the line. I also forgot to mention my car hits the rev limiter on 1-2 shift. I ran the 14.60 and hit the limiter on 1-2. That's why I think my hangup is the trans. AND I didn't notice a damn thing when I put the 73mm MAF on the car.
 
The MAF probably doesn't do much for you without a larger TB to go along with it. You can also have a chip burned to either remove the rev limiter, or raise it up to 5600 rpm or so.
 
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