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Is a bulletproof auto tranny needed for 450-500hp build?

15K views 25 replies 16 participants last post by  Powerstroke Racer 
#1 ·
Just as the title says. What are all you members running for auto tranny mods in this hp range? When I purchased my '01 the guy stated it had a Jasper rebuild put in it about a year ago, I ask him if it was a Monsterbox tranny but he didn't know for sure. I'm wondering if a guy can get away with a good tranny cooler, torque converter, and valve body with the stated hp range? Any thoughts?

John
 
#2 ·
i would recommend a john woods transmission. mine has been working flawless.being that there would be no real bullet proof transmission. you would build one or purchase one with the best parts money can buy to help prevent failure.
 
#3 ·
it all depends on how you drive it. But i would recommend either a JW or BTS. With 500 hp on tap it would be hard for me to take it easy
 
#4 ·
I had just a converter and shift kit in mine for a loooong time at around the 450ish level. Wasn't 'til I added da juice that I had to get a full built trans. Even then it never slipped, got hot, or anything. I just happened to find pieces of clutch in the pan. That was at over 8000lbs on 37's drivin' it like I stole it too.
 
#5 ·
From my experience, Jaspers are junk. The factory trans that was in the truck usually lives longer than the Jasper that replaces it, and this is on trucks with just a chip or a lift/tires and a chip.

IMO, I wouldn't throw the cash out for a good tc and vb on a Jasper, they are just too cheaply built. Don't eveng get me started on their rebuilt engines. :doh:

If you can't afford a BTS or JW trans, look into Racerx transmissions or get the parts from Racerx and have a good rebuilder build your's for you.

Dave
 
#7 ·
Glad you posted up, I thought you were running this in one of your trucks.

If I were to purchase a complete transmission, it would either come from BTS or Bowler transmissions.

John
 
#10 ·
I agree with you guys on Jasper's products believe me. I live 30 miles from the place and have heard all kinds of stories about there quality. I'm kind of skeptical to see how long it will hold up with a converter and valve body.

John
 
#11 ·
For the record, DI is doing transmissions too now so you may want to check them out also.
 
#12 ·
mine has a bd valve body and t/c with a jasper and has held up well so far but i never beat the truck like i stole it either, i just run it hard at the track, been perfect for 45,000 miles that i've owned it. Time will tell though.
 
#13 ·
Ive got a 6 speed in my 2000, what mods do I need and what are some good clutches for that hp range?
 
#14 ·
I am very happy with the transmission that John Wood built for me. With the DP programming, it shifts perfectly for me. John installed a billet converter with my tranny. The new programs I got from Jody for my chip keep the converter locked down to around 22mph and it locks up around 30mph. I had installed a lockup switch in my truck but really do not need it anymore with these new programs. Also, the harder I get on the throttle, the firmer the tranny shifts.
 
#24 ·
The first time i layed mine to the floor with my old setup, it broke. Did it in o/d and it was the forward clutch drum. Splines stripped out. That was at 450 hp. I guess you get lucky sometimes and i wasnt. It had a sonnax kit at the time only and 210k miles.
 
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