Cracked pg case number 2 of the year

Cracked stock case number 2 of the year tonight. This time I'm going to have a trans built that I don't have to worry about. What's your opinions as far as case, first gear, pro brake brand, etc. I was running a 1.76 first gear, tci pro brake, jw bell. Thanks!

Oh, and 840hp 557 in a 3200 lb mustang leaving @ 3800 running a 6.0 1/8 mile class.

How is it mounted?

richter69 wrote:How is it mounted?

x2

Running a front motor plate, somewhat of a mid plate but not very structural, more for hanging the trans when the engine is out, and on a stock mustang crossmember with an adapter plate. Cracked the first case on a chassis dyno, cracked this one on the track.

Get rid of the tranny mount. you should never run one with a mid plate.

powerstrokeace wrote:Get rid of the tranny mount. you should never run one with a mid plate.

But it's not structural. Made out of maybe 16 gauge.

Is the tranny mount solid? if so it should not be. and remove the mid plate.

Ace

No it has a rubber trans mount.

What's the line pressure? Where did it crack?

whatbumper wrote:What's the line pressure? Where did it crack?

I'm not sure of the line pressure nor where this one cracked. Still have it on the trailer because I am going to run it foot brake tomorrow anyway for points. As long as I'm not on the brake, it don't throw fluid. The last one cracked where the tail housing meets the case above the brake solenoid.

Blakes got a great deal on aftermarket case and 1.80 strait cut PG's.

Look him up IDT-572

dfree383 wrote:Blakes got a great deal on aftermarket case and 1.80 strait cut PG's.

Look him up IDT-572

Snake!!! I need some parts man!

i realy like my reid case.i dont run a mount and have a thin midplate but also have limiters on both sides to the block.

Both of my trannys have JW Ultra cases and I have been happy with the case design. If you already have he ultrabell, the JW case would be nice. The other aftermarket cases are all fine too.
It would be good to figure out the root cause of the OE case failure. The best setup is subject to 2 or 3 opinions, but I like a 1/4" motor plate, 12 ga (.100" or so) mid plate and a rubber or urethane trans mount. Of course, the engine needs lateral limiters. The JW case is so thick and heavy, it can survive about any type mounting.
Since llots of Chevy guys are now buying other afftermarket cases that have Chevy bells, you can usually find deals on used JW Ultra cases. Maybe look at Racing Junk..?
Keith Fulp
678-458-2033

I have a buddy that cracked two cases last year. His driveshaft was too long. On launch the rotation of the rear would let the yoke smack the tail shaft. He broke the tail shaft once and the case both times. Just something to check

if you broke a case you have something in a BIND, I see 1000 hp car running stock cases with no problems at all. you can not have it supported in 3 spots front and talishaft or front and mid plate but not all 3 it WILL BREAK something... you say the mid is not really a support but if it is touching it is a support and it will break the trans somewhere cuz it is aluminum....

the Coug wrote:if you broke a case you have something in a BIND, I see 1000 hp car running stock cases with no problems at all. you can not have it supported in 3 spots front and talishaft or front and mid plate but not all 3 it WILL BREAK something... you say the mid is not really a support but if it is touching it is a support and it will break the trans somewhere cuz it is aluminum....

Also where he described the first one breaking sounds like too much line pressure for a stock case. We've mounted all three spots in every car we've built and have not had any torsional cracking due to it. We've only had them crack when the pressures where jacked up way too high.

I agree the rubber trans mount should not be the issue even w the midplate.............not that you need a mount but thats another can of worms lol.

It have to agree with the previous post either line pressure or the driveshaft bottoming out. Both need to be checked.

Thanks guys. Good idea on the checking yoke end play. Will do. Regardless, new trans will be in by next race and it will be an aftermarket case. I ran it footbrake today just to get some points and ended up in the quarters (Doesn't leak when not on the brake). Got some lucky breaks though

do you have limiters on it?

cool40 wrote:do you have limiters on it?

No sir. Please explain. I am imagining from what you are saying cable or chain with NO slack attached to the frame to absorb torque. Am I close?

No not a Chain, tube and clevis's or bars.

Do you have Limiters on the side of the engine to the frame to stop Front to rear movement of the engine on launch and deceleration? If not you need to have them, that could be the root of your problem.

No, no limiters whatsoever...