Cracked C4 Case

Joe Grippo · 05-10-2012, 09:10 AM

Well I had the race car out the other weekend for the first time this year and on the 3rd pass it seems I cracked the transmission case and promptly sprayed type f everywhere. I found a very small crack about 2 inches from the tail shaft on the main case right at the top along the casting seem. I have a front engine plate, stock motor mounts and the trans uses a poly mount. I also have a really beefy JW Ultra Bell. The car wheelstands every run and I have had this set up for about 10 years and have never had a problem. This past off season I did some chassis work and added a full cage, dash bar and bars off the dash bar to the rear of the shock towers. The car leaves hard and square with no twisting. This was a new trans with less than 25 runs on it. So I am wondering if its just a coincidence that the case cracked or do I have to rethink the transmission mounting based on the more rigid chassis? It should not be solid mounted I assume. Or am I missing something else that could have caused this situation? I should add that I know a mid-plate would probably be a good idea but it's not in the budget this year.

It is a bracket car not a class car but I was curious as to what some of the Super Stock guys are doing if they have a similar set up...Thanks.

Mike Graham · 05-10-2012, 10:08 AM

I run a very similar setup except with a stock rubber trans mount. No problems.
I think your problem was just luck of the draw.
Mike Graham

05-10-2012, 09:10 AM	#1
Joe Grippo Member Join Date: Apr 2002 Location: Elverson, Pa Posts: 158 Likes: 123 Liked 41 Times in 4 Posts	Cracked C4 Case Well I had the race car out the other weekend for the first time this year and on the 3rd pass it seems I cracked the transmission case and promptly sprayed type f everywhere. I found a very small crack about 2 inches from the tail shaft on the main case right at the top along the casting seem. I have a front engine plate, stock motor mounts and the trans uses a poly mount. I also have a really beefy JW Ultra Bell. The car wheelstands every run and I have had this set up for about 10 years and have never had a problem. This past off season I did some chassis work and added a full cage, dash bar and bars off the dash bar to the rear of the shock towers. The car leaves hard and square with no twisting. This was a new trans with less than 25 runs on it. So I am wondering if its just a coincidence that the case cracked or do I have to rethink the transmission mounting based on the more rigid chassis? It should not be solid mounted I assume. Or am I missing something else that could have caused this situation? I should add that I know a mid-plate would probably be a good idea but it's not in the budget this year. It is a bracket car not a class car but I was curious as to what some of the Super Stock guys are doing if they have a similar set up...Thanks. __________________ Time Wasters....http://www.flickr.com/photos/joe_grippo/sets/ http://www.youtube.com/user/JoeGrippo?feature=mhum Last edited by Joe Grippo; 05-10-2012 at 10:06 AM.

05-10-2012, 10:08 AM	#2
Mike Graham Member Join Date: Jul 2002 Posts: 410 Likes: 1 Liked 341 Times in 67 Posts	Re: Cracked C4 Case I run a very similar setup except with a stock rubber trans mount. No problems. I think your problem was just luck of the draw. Mike Graham