J-Mod Question

[Dusstbuster]

So I've been reading up on the J-mod and remember hearing awhile back that the reason you're supposed to turn OD off in a car while racing is because you can destroy the OD gear if it shifts at WOT due to some slippage. Will the J-Mod reduce/remove this issue as far as slipping or misshifting into OD and allow you to keep OD on? I know it firms up the shifts and reduces tranny wear so I'm assuming it helps the OD shift as well?

 

[TGJ]

So I've been reading up on the J-mod and remember hearing awhile back that the reason you're supposed to turn OD off in a car while racing is because you can destroy the OD gear if it shifts at WOT due to some slippage. Will the J-Mod reduce/remove this issue as far as slipping or misshifting into OD and allow you to keep OD on? I know it firms up the shifts and reduces tranny wear so I'm assuming it helps the OD shift as well?

You have brought up the biggest weakness of the 4R70W. The JMod helps shifts into overdrive but it does not correct the problem of shifting into OD at WOT. There is no fix currently that will allow a WOT shift in OD, not even a fully built 4R70W, you will break something and not neccessarily OD. I have seen input shafts break as well.

 

[Dusstbuster]

Well that's depressing

 

[merc123]

I don't know much about the stang's auto tranny, but you're seriously going fast enough to hit OD at WOT when racing?

 

[Dusstbuster]

I don't know much about the stang's auto tranny, but you're seriously going fast enough to hit OD at WOT when racing?

Easily...the car goes through the first 3 gears pretty damn quick with the 3.73's

 

[Kilgore Trout]

Overdive is simply not designed to take a lot of torque. The j-mod will not redesign the trans to make it something it isn't

 

[Dusstbuster]

Overdive is simply not designed to take a lot of torque. The j-mod will not redesign the trans to make it something it isn't

I know I was just hoping that the firmer shifts would help reduce the stress of the shift on OD. Whats even worse is that if it comes to that point in the RPM range and you have OD off, the tranny overrides the "off" and kicks it into OD anyways.

 

[propellerhead]

I have not seen any credible data on this idea of breaking something by shifting into 4th at WOT. I still think it's a myth.

 

[CobraRed_96_GT]

this is one of many reasons i have a new OD servo gear and hardened input and intermediate shafts from the rebuild. The OD gear is funny, i have 3.73's and w/ a 98-100mph trap on the 1/4 it really needs to shift

 

[TGJ]

I have not seen any credible data on this idea of breaking something by shifting into 4th at WOT. I still think it's a myth.

http://forums.tccoa.com/showthread.php?t=67549

Still a myth?

I know I was just hoping that the firmer shifts would help reduce the stress of the shift on OD. Whats even worse is that if it comes to that point in the RPM range and you have OD off, the tranny overrides the "off" and kicks it into OD anyways.

Nothing that a tune can't fix.

 

[propellerhead]

http://forums.tccoa.com/showthread.php?t=67549

Still a myth?

Wow! That is the first time I've seen that. Everything else for the past few years has been "I heard..." or "They say..."

Thanks.

 

[CobraRed_96_GT]

wow, yeah - od off at wot FTW. You shouldn't need to use OD for a WOT 1/4 mile n e wayz

 

[03ghoststang]

wow even though i have heard of not doing that.........i am still not going to be doing that O/D shift at WOT = FTL


and as far as the J-mod goes it's just modifying the valve body of the trans, unless you open the trans up and swap stuff out that is all your doing

 

[justinschmidt1]

my auto over rides and shifts into o/d at like 5k for some reason...its pretty stupid.

 

[Dusstbuster]

my auto over rides and shifts into o/d at like 5k for some reason...its pretty stupid.

Yeah same here...

 

[san~man]

Mine don't....like TGJ said, it's in the programming.

 

[Dusstbuster]

Will a Predator AND Xcal fix it? The guy I'm planning on getting dynotuned with uses a Predator.