High Mileage Jmod

[1988mgm]

Hello everybody I've been thinking about jmodding my tc but im afraid the mileage is to high. It has 170xxx miles so im afraid its never been open and Ive heard that if I do the jmod and fluid/filter it will cause slippage should I be worried or not? Thanks!!

[Louis]

I wouldn't do it, the harsher shifts from a J-mod would probably destroy it with that high of mileage. If the fluid is original, I'd be leery of even changing that.

[88grandmarq]

what year town car?

[Billy]

I wouldn't do it, the harsher shifts from a J-mod would probably destroy it with that high of mileage. If the fluid is original, I'd be leery of even changing that.

Shift harshness doesn't change a bit if you don't change the springs. I know firsthand.

[sly]

though, if you rebuild it (soft parts) and do the j-mod and refill with mercV and put a smaller diameter torque converter on it (no more than 3000 stall... probably more around 2600 for stall)... it'll probably last forever behind the stock or even mildly modded engine.

[Louis]

though, if you rebuild it (soft parts) and do the j-mod and refill with mercV and put a smaller diameter torque converter on it (no more than 3000 stall... probably more around 2600 for stall)... it'll probably last forever behind the stock or even mildly modded engine.

That's the key, better to rebuild it along with the drilling/springs for the J mod.

[SVT98t]

I did the only separator plate on my 93 at 155k.It's a decent shift, but nothing like snappy shifts from a full J-Mod. The Tank's still going strong at 221k.

-ryan s.

[gadget73]

I'd be real tempted to say leave it alone unless you have spare funds for an "oh shit" moment.

[88grandmarq]

Hello everybody I've been thinking about jmodding my tc but im afraid the mileage is to high. It has 170xxx miles so im afraid its never been open and Ive heard that if I do the jmod and fluid/filter it will cause slippage should I be worried or not? Thanks!!

What year town car?

I have done the Jmod on several trucks with excess of 200k, no issues.

If this a 96-97 car, you will need to drill the holes differently, since it doesn't have a mechanical diode one way clutch.

[sly]

I'd be real tempted to say leave it alone unless you have spare funds for an "oh shit" moment.

especially this.

[1988mgm]

It is 1996 im sorry for not putting up there

[88grandmarq]

** THIS APPLIES to 96-97 Transmissions ONLY ***

Drill hole #1 to .160" this is a #20 drill bit

Drill Hole #2 to .081" (#46 drill bit) for a mild shift, or .093" (3/32 drill bit) for a firmer shift

Drill hole #3 to .180" if not already that large this a #15 drill - you can use a 11/64" drill bit in a pinch (.1719")

Drill hole #4 and #5 to .081" - you can use a 5/64" in a pinch (.078") It is not recommended you make these holes any larger than .081".

Drill hole #6 to .125" - 1/8" drill bit

Hole #7 is completely optional - I typically do not drill this hole.

hole #8 should not apply to your year model.

Drill hole #9 and #11 to .110" - 7/64 drill bit.

hole #10 is completely optional, I usually drill to .093" - 3/32 drill bit.

While you have the Valve body off, this is good time to update the 1-2 and 2-3 accumulator pistons with the new style bonded rubber units.

I also highly recommend replacing the pressure regulator valve with the Sonnax replacement valve and pressure spring. These valves are notorious for wearing, which will cause low line pressure.

http://www.sonnax.com/parts/2398

For Note #4, there is a slot in the gasket next to a hole, this is slot 1. use a razor blade or xacto knife and make this slot wider, open it up to .100"
what I do is lay a 3/32" drill bit down and use it as a guide, then score the lines in the gasket material with the razor blade, then make the cuts and remove the extra gasket material

Refill with 10qts for mercon V fluid and should shift great.

BTW, I do NOT recommend removing any of the accumulator springs. doing so makes the shifting harsh and if the line pressure is low from other worn parts the shifts will be erratic.

[sly]

so want to do this on the vic... but I'll probably wait until I do some other crazy mods and really need that firm shift... and when it's not my wife's DD.

[88grandmarq]

so want to do this on the vic... but I'll probably wait until I do some other crazy mods and really need that firm shift... and when it's not my wife's DD.

on your 93? is the transmission original?

[sly]

yeah... it's still the AODE... but it's got a 24-2800 stall converter on it and a rebuild at 106K miles. over 210K now.