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Just did the jmod and wow!

Old 12-19-2011, 10:49 PM
  #1  
Rush1791
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Talking Just did the jmod and wow!

So ive been planning on doing this for a while but was just too lazy. I used this website. http://www.crownvic.net/tech/4R70Wnotes.pdf

The only problem was in the first step:

• Disconnect the transmission cooler return line where it changes from a hose to a steel line.
There are two lines coming out of the cooler, you want the upper one. Follow it down; it
should still be the upper line at the point of change.
• Have someone hold it steady and point it into an oil pan. Start the car and let it idle while
the transmission fluid is pumped out in a continuous stream. Shut the car off as soon as the
stream starts to sputter or the flow decreases significantly.

On my mustang its a steel line all the way to the tranny so i couldn't drain it this way... I had to do it the messy way. Other than that it was all good.

Ok now to the good part. The shifts are totally improved. Fast and strong. I was alittle afraid that removing the springs would make it too harsh but it doesn't. I floored it going on to the freeway so I didn't get the 1-2 but the 2-3 was so fast the 315 out back couldn't help but get loose. I had to get off the gas so i wouldn't lost it. overall very pleased with the Jmod. can't wait for 4.10's and the tuner!
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Old 12-19-2011, 11:18 PM
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WannaBeGearHead
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People don't realize what a little transmission work does to the autos. If you're impressed with the J-mod you'll be extremely happy with 4.10s.
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Old 12-20-2011, 01:00 PM
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Rush1791
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Yup for the 4.10's should i go with the 31 spline conversion because in the future im planning on getting slicks plus a higher stall and idk if the 28's would hold up now that its shifting way faster.
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Old 12-20-2011, 09:35 PM
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cisurfer
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If you're in there go 31. It's very easy to change over once it's all apart
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Old 12-20-2011, 11:18 PM
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WannaBeGearHead
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While I agree with what cisurfer said I don't think you'll break anything with an auto. If you go transbrake then that's a different story.
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Old 12-21-2011, 04:54 PM
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justinschmidt1
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Originally Posted by WannaBeGearHead
People don't realize what a little transmission work does to the autos. If you're impressed with the J-mod you'll be extremely happy with 4.10s.


JMOD, 4.10s and a 3500 stall converter....

Autos are the **** when they are set up right
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Old 12-21-2011, 04:55 PM
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Originally Posted by Rush1791
Yup for the 4.10's should i go with the 31 spline conversion because in the future im planning on getting slicks plus a higher stall and idk if the 28's would hold up now that its shifting way faster.
As gearhead just said, no need to upgrade the splines on the auto.

Ive got a 3800 stall, 3.73s, vortech gt cutting 1.6x 60 foots on slicks and have no problems at all.

The auto just wont shock the axles without a transbrake.
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Old 12-23-2011, 03:21 PM
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Originally Posted by Rush1791
So ive been planning on doing this for a while but was just too lazy. I used this website. http://www.crownvic.net/tech/4R70Wnotes.pdf

The only problem was in the first step:

• Disconnect the transmission cooler return line where it changes from a hose to a steel line.
There are two lines coming out of the cooler, you want the upper one. Follow it down; it
should still be the upper line at the point of change.
• Have someone hold it steady and point it into an oil pan. Start the car and let it idle while
the transmission fluid is pumped out in a continuous stream. Shut the car off as soon as the
stream starts to sputter or the flow decreases significantly.

On my mustang its a steel line all the way to the tranny so i couldn't drain it this way... I had to do it the messy way. Other than that it was all good.

Ok now to the good part. The shifts are totally improved. Fast and strong. I was alittle afraid that removing the springs would make it too harsh but it doesn't. I floored it going on to the freeway so I didn't get the 1-2 but the 2-3 was so fast the 315 out back couldn't help but get loose. I had to get off the gas so i wouldn't lost it. overall very pleased with the Jmod. can't wait for 4.10's and the tuner!
Is it extremely hard to do? how long did it take you
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Old 12-23-2011, 04:29 PM
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justinschmidt1
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Originally Posted by Itsme03gt
Is it extremely hard to do? how long did it take you
No, its not hard to do if you know how to follow instructions and have any mechanical skill what so ever.

Have you changed your trans filter before?

You have to drop the pan, pull like 20 small bolts off and the valvebody will drop down from the transmission.

Then your just following directions and drilling a few holes and putting it back together with new springs or without springs all together.


You can probably have it done and back together in 2-3 hours for someone whos never done it before.
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Old 12-24-2011, 11:29 PM
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Yeah its not hard just kinda messy. It too me about three hours from start to finish. I would recommend to take the springs out just be carefully when you take out the snap ring because it's under spring tension and if your not careful it will shoot out the piston followed by more tranny fluid, ask me how I know...
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