J-Mod 4R70W or Swap in 4R75W ?

[VictorCrown]

Hi Guys,

I'm new in this section of the forum given I have not yet completed the Marauder engine implant in my older Panther.

It is a rare 'Towing' version of Crown Vic LX which a Police Mechanic in the Crownvic.net forum told me is mechanically identical to the Police Pursuit model but in luxury trim. It thus has the same higher transmission and rear axle ratios which did make it really fly off the line even with the stock engine. Now it is getting a brand new 2004 Factory Crate DOHC. :cool3:

So to make a long question short, would you recommend keeping the tranny as is, doing the J-Mod, or finding a donor 4R75W? I'm open to any suggestions, even wild ones. :loco:

It will not have forced intake, but will be a natural with the following mods:
PHP Spacer, Evenflow Cooling, Steeda Pulleys, K&N Intake, SW Longtube Headers, Hi-flow Cats, Dynomax Ultraflo X-Pipe, Borla Mufflers and SCT dyno tuned chip.

Thanks for any advice 'cause I'd rather finish the mods before burning the chip! :up:

[cvpiftw]

The guys at CVN are pullin your leg lol. They are idiots..


the 4r70w and 4r75 are the same gear ratios.... just internal strength differences. If you get a built trans.... that will solve all the issues.... IIRC a built 4r70 is much better than a 4r75. Do the Jmod and get the trans built while your in there IMO. If not getting a built trans... get a Jmod. Make sure the line pressure in the tune isnt set too high and id recommend getting a programmer vs a chip so you can make minor modifications to the tune if need be.

A truck 4r70w is stronger than a car 4r70w BTW. Just a idea, alas you would have to swap the tailshaft and a few other parts IIRC.

[VictorCrown]

If you get a built trans.... that will solve all the issues...
Hi cvpiftw,

Thanks for taking the time to set me straight. The project car is getting expensive and I want to make sure that I get any extra mods right the first time around.

Would getting a Built Transmission be expensive? Does anybody build them better and/or cheaper? Thanks if you have an idea, or I'll spend some time playing with the search function. ;)

Vic