Breaking bell housings

jbt352 · 03-28-2014, 12:34 PM

1977 Chevy Malibu,stock rear supspension with urethane control arm bushings.
Small block running 13:60/13:80's(1/4 mile)
4:11 gear.
turbo 350.
leaves nice.
Rubber trans mount.
Solid motor mounts.
Car does not twist when it leaves(not enough power).
No vibrations, car feels smooth.
I have not checked the pinoin angle yet.
Why would this thing break the bell housing????
Any ideas would be great.

HandOverFist · 03-28-2014, 12:42 PM

How long have you owned the transmission? Possibly was cracked in another application?

Mike Pearson · 03-28-2014, 12:49 PM

Get rid of the rubber mount. cut the broken bell housing off and put an ultra bell on your trans.

Alan Roehrich · 03-28-2014, 01:34 PM

I would never use a steel or solid mount on a transmission. I've put in dozens of race car transmissions.

I use an ordinary stock replacement mount, with two radiator hose clamps around it as a safety device. Or a urethane mount. In 30 years of working race cars, including a lot of years as the person in charge of race car work in a well respected transmission shop, I have never seen a properly installed rubber or urethane transmission mount cause a broken case. But I have stopped several cars from breaking cases by replacing a steel mount with a correctly installed rubber or urethane mount.

If I'm not using motor plates, I use urethane mounts, or one steel mount on the driver's side and a urethane mount on the passenger side.

You do have flex, a vibration, or a misalignment. You may not have it identified, but it is there.

Adding a bolt on bellhousing merely moves the weak point to the case behind the pump, and when it breaks there, it will dump fluid under your tires.

Jim B · 03-28-2014, 02:02 PM

Another item to check would be to make sure the driveshaft slip yoke is not bottoming out against the output shaft splines. (Manually move the driveshaft forwards and backwards from the rear u-joint and make sure the driveshaft is not too long or too short) Make sure there are no broken/damaged rear suspension components that would allow the rear to move forward or rotate on the leave. I also assume the shaft length to tubing diameter/wall thickness combination and straightness are not causing a harmonic whip. (mostly seen in an insufficient driveshaft length to tubing diameter relationship) Also any history of cracked flex plates? It wouldn't hurt to check the pinion angle.

Jim Kaekel · 03-28-2014, 02:05 PM

Personally, I would ditch the steel motor mounts and replace them with stock units. I believe either all steel, or all rubber mounts. Then, install a torque strap on the left front of the engine.

Alan Nyhus · 03-28-2014, 02:46 PM

Another culprit can be the bellhousing dowel pins, if they've been changed. Some of the after market extra length pins are a bit bigger i.d. than the factory ones, causing the case to be stressed when bolted to the block. -Al

Jeff Niceswanger · 03-28-2014, 02:47 PM

Rossler has told me many times, that too much pinion angle breaks transmissions more than anything. He must see a lot of that.....

Alex Denysenko · 03-30-2014, 04:47 PM

Quote:

Originally Posted by Alan Roehrich

I would never use a steel or solid mount on a transmission. I've put in dozens of race car transmissions.

I use an ordinary stock replacement mount, with two radiator hose clamps around it as a safety device. Or a urethane mount. In 30 years of working race cars, including a lot of years as the person in charge of race car work in a well respected transmission shop, I have never seen a properly installed rubber or urethane transmission mount cause a broken case. But I have stopped several cars from breaking cases by replacing a steel mount with a correctly installed rubber or urethane mount.

If I'm not using motor plates, I use urethane mounts, or one steel mount on the driver's side and a urethane mount on the passenger side.

You do have flex, a vibration, or a misalignment. You may not have it identified, but it is there.

Adding a bolt on bellhousing merely moves the weak point to the case behind the pump, and when it breaks there, it will dump fluid under your tires.

I agree 100% solid motor mounts and a poly trans mount is the best way to go

Greg Barsamian · 03-31-2014, 08:55 AM

One trick that Alfe Weibe shared with me was to use "Hockey Puck's" in place of Body Mounts on GM "A" and "G" body (full-frame) cars where aftermarket mounts are unavailable! Just drill holes in them & replace the worn and sometimes deteriorated body mounts!

Reasoning is that you are "making the body part of the chassis" by adding stiffer body bushings, it will "decrease"the flex that the "factory rubber bushings" offer in absorbing vibrations, body twist, and ride comfort that "stock body mounts" are supposed to do!

More often you will also find with "stock body mounts" the body lines will move as body bushings wear out, signs that the body is actually twisting.

Just make sure that "during installation", you tighten the body mounts with the weight of the body on the chassis and suspension, "NOT ON A LIFT OR JACK STANDS! This will bind the chassis (found out the hard way) and in "Stick Applications" "buckle the rear quarters"
I final tighten them on an open car trailer.

Alfe's way of telling me to "Go Puck Myself" LOL

03-28-2014, 12:34 PM	#1
jbt352 Junior Member Join Date: Feb 2010 Posts: 20 Likes: 0 Liked 2 Times in 2 Posts	Breaking bell housings 1977 Chevy Malibu,stock rear supspension with urethane control arm bushings. Small block running 13:60/13:80's(1/4 mile) 4:11 gear. turbo 350. leaves nice. Rubber trans mount. Solid motor mounts. Car does not twist when it leaves(not enough power). No vibrations, car feels smooth. I have not checked the pinoin angle yet. Why would this thing break the bell housing???? Any ideas would be great.

03-28-2014, 12:42 PM	#2
HandOverFist VIP Member Join Date: Oct 2013 Location: Gulf Breeze, FL Posts: 1,651 Likes: 8 Liked 33 Times in 16 Posts	Re: Breaking bell housings How long have you owned the transmission? Possibly was cracked in another application? __________________ Rich Taylor I/SA - 321

03-28-2014, 12:49 PM	#3
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,441 Likes: 611 Liked 1,909 Times in 573 Posts	Re: Breaking bell housings Get rid of the rubber mount. cut the broken bell housing off and put an ultra bell on your trans. __________________ Mike Pearson 2485 SS

03-28-2014, 01:34 PM	#4
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,100 Likes: 1,551 Liked 1,778 Times in 404 Posts	Re: Breaking bell housings I would never use a steel or solid mount on a transmission. I've put in dozens of race car transmissions. I use an ordinary stock replacement mount, with two radiator hose clamps around it as a safety device. Or a urethane mount. In 30 years of working race cars, including a lot of years as the person in charge of race car work in a well respected transmission shop, I have never seen a properly installed rubber or urethane transmission mount cause a broken case. But I have stopped several cars from breaking cases by replacing a steel mount with a correctly installed rubber or urethane mount. If I'm not using motor plates, I use urethane mounts, or one steel mount on the driver's side and a urethane mount on the passenger side. You do have flex, a vibration, or a misalignment. You may not have it identified, but it is there. Adding a bolt on bellhousing merely moves the weak point to the case behind the pump, and when it breaks there, it will dump fluid under your tires.

03-28-2014, 02:02 PM	#5
Jim B Member Join Date: Dec 2008 Posts: 100 Likes: 0 Liked 1 Time in 1 Post	Re: Breaking bell housings Another item to check would be to make sure the driveshaft slip yoke is not bottoming out against the output shaft splines. (Manually move the driveshaft forwards and backwards from the rear u-joint and make sure the driveshaft is not too long or too short) Make sure there are no broken/damaged rear suspension components that would allow the rear to move forward or rotate on the leave. I also assume the shaft length to tubing diameter/wall thickness combination and straightness are not causing a harmonic whip. (mostly seen in an insufficient driveshaft length to tubing diameter relationship) Also any history of cracked flex plates? It wouldn't hurt to check the pinion angle. Last edited by Jim B; 03-28-2014 at 02:10 PM.

03-28-2014, 02:05 PM	#6
Jim Kaekel VIP Member Join Date: Jul 2002 Location: Michigan Posts: 1,226 Likes: 133 Liked 529 Times in 107 Posts	Re: Breaking bell housings Personally, I would ditch the steel motor mounts and replace them with stock units. I believe either all steel, or all rubber mounts. Then, install a torque strap on the left front of the engine. __________________ Jim Kaekel 3836 STK

03-28-2014, 02:46 PM	#7
Alan Nyhus VIP Member Join Date: Dec 2002 Location: Lower Dakota territory Posts: 1,180 Likes: 1,074 Liked 799 Times in 236 Posts	Re: Breaking bell housings Another culprit can be the bellhousing dowel pins, if they've been changed. Some of the after market extra length pins are a bit bigger i.d. than the factory ones, causing the case to be stressed when bolted to the block. -Al __________________ "That'll never work....."

03-28-2014, 02:47 PM	#8
Jeff Niceswanger Senior Member Join Date: Jul 2003 Posts: 872 Likes: 673 Liked 962 Times in 352 Posts	Re: Breaking bell housings Rossler has told me many times, that too much pinion angle breaks transmissions more than anything. He must see a lot of that..... __________________ Jeff Niceswanger 3740 SS

03-31-2014, 08:55 AM	#10
Greg Barsamian VIP Member Join Date: Jan 2002 Location: Central Massachusetts Posts: 1,398 Likes: 708 Liked 410 Times in 94 Posts	Re: Breaking bell housings One trick that Alfe Weibe shared with me was to use "Hockey Puck's" in place of Body Mounts on GM "A" and "G" body (full-frame) cars where aftermarket mounts are unavailable! Just drill holes in them & replace the worn and sometimes deteriorated body mounts! Reasoning is that you are "making the body part of the chassis" by adding stiffer body bushings, it will "decrease"the flex that the "factory rubber bushings" offer in absorbing vibrations, body twist, and ride comfort that "stock body mounts" are supposed to do! More often you will also find with "stock body mounts" the body lines will move as body bushings wear out, signs that the body is actually twisting. Just make sure that "during installation", you tighten the body mounts with the weight of the body on the chassis and suspension, "NOT ON A LIFT OR JACK STANDS! This will bind the chassis (found out the hard way) and in "Stick Applications" "buckle the rear quarters" I final tighten them on an open car trailer. Alfe's way of telling me to "Go Puck Myself" LOL Last edited by Greg Barsamian; 03-31-2014 at 08:58 AM.