J-Mod Warning, Read!

[merc6]

Is the J mod similar to or better than increasing the shift firmess on say a diablo or Xcal2?

[Zack]

Steve (Killjoy) brought me his trans a few months back to have rebuilt (by my Ford Tech) and It got the J-Mod and Spiraloc snap ring.
Last week, Steve calls and tells me it wont go in reverse, WTF? The trans has 3000 miles on it and Steve's car barely makes any power :D.

So Steve yanked the trans and took brought it to Seymour. It is now disassembled and the diagnosis is:

Simple but deadly. The J-Mod calls for the removal of the 2-3 accumulator piston spring. This forces the piston upward into the bore at all times which keeps pressure and capacity up. Problem is, there is now nothing to keep the piston straight in the bore. Guess what, the lip of the piston folded over and caused the direct clutch to burn up. Everything else is fine.

The guy I have do the transmissions warned me of his, but thousands of cars have the J-mod with no issue, so why change what works well?

The fix for this is to set a bolt or some rigid metal object in between the piston and the cap the snap ring holds in place. This will ensure the piston stays straight in the bore and eliminates the possibility of failure.

Just thought id share :beatnik:

[TooManyFords]

Just thought id share :beatnik:

This thread is worthless without pictures!

Do you have any to show how this mod is done?

Thanks

John

[Raudermaster]

Hmm, very interesting. The guy I know who does J-Mod's, I better double check with him to see if he knows this if I plan to get one.

[KillJoy]

I drained the TC last night. The Fluid seems to have a shiney metal flow to it. :( I am going to be sending it out to be rebuilt by Circle D Specialties. I spoke w/ Chris, and he SEEMED to know what he was talking about. :up: Darrin @ BC Automotive recommended them, so...they should do just fine!!

About the only good thing that came from this, is that I can now remove the Trans in 2 hrs :D

KillJoy

[Zack]

This thread is worthless without pictures!

Do you have any to show how this mod is done?

Thanks

John

I stayed home to oversee the roofers at the house today, so no I dont have pics.

Just imagine the lip of an accumulator piston folded over. :stupid:

[RVT04]

me no savvy jmod?
i had an artcarr level II tranny rebuild with a pi tc and forced tailshaft lube external line with a deep pan and temp sensor to guage in console where lighter used to be, all done by dr over two years ago 11,000 miles street, strip and track. some serious pounding, but mostly tire smoking fun and not a sign of trouble, worth every penny!:burnout:

[sailsmen]

U had the jmod.

[RCSignals]

We need Jerry to update the requirements for the j-mod.

Found his post


I obviously would recommend the J-mod (do you know I hate that phrase). What I really need to do is make an update to the article for Marauder specific vehicles. Some of the things I recommended when I wrote that, I was able to get into production at Ford.

What needs to happen is this; we need someone with a stock Marauder trans, a hoist, and few days to try some different things. I'm sure Dennis would offer his shop.....any volunteers?

j

[Krytin]

For once I must be lucky! 45K+ miles with said spring removed and no problem.....

Now that I've said this I'm sure I'll pay for it with a failure!

Next fluid change I'll be looking into this!