Has your transmission ever broke in half? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Adam12 · 10-24-2002, 11:32 PM

Today I went to show my brother that we finaly got my truck running a few weeks ago. I cant go anywhere because I have no driveline but it fires up fine and runs sweet. its a 454 block bored to 481 with a th-400 trans today i fired it up and reved it up a lil then I felt the pedal give and heard the sound of metal falling on the cement. I get out and look under the hood and the motor was sagging bad in the back, so I look under and see that my transmission is nearly upside down! the bell housing on the transmission just broke somehow and chucks of metal were on the ground and tranny fluid was everywhere. anyone know what may have caused this? could it be because there was no driveline installed? oh yeah it ripped the trans mount all up too. I asked around and no one I have talked to has ever seen anything like this.

crazy longhorn · 10-24-2002, 11:36 PM

Ddddaaamn......nope, i have never broke one in half

Adam12 · 10-24-2002, 11:36 PM

Wish I had a camera to show you guys. I see if I can borrow one tomorrow.

Hooter · 10-24-2002, 11:41 PM

wow

no I think you are the first one to ever do that. Gives whole new meaning to "tranny drop"

Longhorn Man · 10-24-2002, 11:47 PM

I've seen one break in 1/2, but it was after a drop onto a cement driveway.

Bowed · 10-24-2002, 11:55 PM

Faulty or improperly installed motor mounts can break a bell housing.

Adam12 · 10-24-2002, 11:56 PM

So if the motor mounts were the case shouldnt I be able to look at them and see some dmg? or somthing? I havent looked at them closly yet figured id wait til tomorrow to take the rest of the bellhousing off.

Bowed · 10-25-2002, 12:19 AM

Check the motor mounts to see if the motor is moving enough to twist a trans that is bolted to its crossmember and mounts. I had a TH 350 that broke its bell housing on a blazer but on that one the trans was touching the tunnel and was probably getting to much pressure on it when I gunned the truck , which was quite often but other wise I have seen a couple of trucks that broke bell housings just from bad mounts.

Adam12 · 10-25-2002, 01:06 AM

ok ill check for that tomorrow.

**GMCPaul** · 10-25-2002, 05:08 AM

Broke 3 of them all attached to the same motor. Talked to a very old and savvy GM mechanic and half way through telling him what happened he says its your thrust bearing in the motor.
Well we pulled the motor checked it out, thrust bearing was bad, replaced that bearing, re-installed and never broke a bell housing again.
Seems that the crank was walking forward then back and this action broke the housing. How was the bearing damaged? My own stupidity I knocked the harmonic balancer on with a block of wood and hammer rather than using a harmonic balancer installer. What can I say I was only 22 and doing what I had seen done before that worked. Now if they make a tool to do a job I use it as that home method isn't always correct. I Hope its your motor mounts.
GMCPaul

yellowgmc · 10-25-2002, 11:38 AM

i blew up an np231 transfer case at 65mph once. big bang, bigger dent in floorboard. no trannys tho.

**COBALT** · 10-25-2002, 11:50 AM

No chevy trannys but I new a guy once that had a bad motor mount on his newly installed 302 in a ford. He was cruising along, and went to pass someone, so his transmission kicked down into lower gear. The motor mount broke, and kinked the accel. linkage. Then it broke the bell housing on the transmission. He had to shut the car off at 50 mph. Hosed his entire driveline.

He was UPSET. Brand new 302 crate and everything.

XXL · 10-25-2002, 02:09 PM

I broke a TH400 bellhousing in two right at the point where it curves into the main body of the transmission. The driver's side motor mount broke on my dual-quad 454 and I thought I was going to fil the truck over on it's side with all the torque that was going on. I also broke the distributor when it hit the firewall.

Kenneth

Maximum Overdrive · 10-25-2002, 03:05 PM

Had one break after I snapped my driveline in two doing about 80 down the interstate. It busted the rear of the tailshaft off and snapped it off from the motor around the bell housing. The busted driveline put about a 6 inch high dent into the floorboard of the cab. Thought a damn bomb went off when the driveline came up into the cab like that. lol

Adam12 · 10-25-2002, 03:16 PM

Oh man! I used a block of wood and a hammer to put the harmonic balancer on! this sucks!

chewed 71'er · 10-26-2002, 07:01 PM

Man alive!! What an ugly lesson in shade-tree mechanics! Guess we need to leave wood blocks and hammers for ford (gag) products.

crazy longhorn · 10-26-2002, 07:24 PM

Adam 12, if you did by chance "mangle the thrust bearing you should be able to feel it as excessive end play in the crank. on a fresh eng you will have in the range of .005 end play. You need to take the belts off to 'feel this". at .005 end play, you probably wont be able to feel any movement , due to oil around the thrust faces of the bearing. I have run some engines with more than ideal clearance, & as long as the counter weights on the crank werent "kissin a mainweb" there wasnt too much problem. take hold of the balancer, & try pushin it back /forth. If you feel quite a bit of movement, you have problems & should check it out. If it feels tight, you might check converter to pump clearance... should be in the range of .1875(3/16), or look for a warped flex plate. more than likely the flex plate is fubar from the grenade, & you wont be able to check clearance till you put another trans in, but as it bolts up there should be a little clearance tween the flexplate & converter( no less than 1/8", & no more than 1/4). Good luck......crazy AL

Grim Reaper · 10-26-2002, 07:41 PM

Well no driveshaft on the tranny seems to me that unless is was a fixed yoke TH400 that you may not have had any fluid in the tranny. Might have seized the torque converter to the pump if that were the case.

67cst · 10-26-2002, 08:24 PM

my buddy had a th350 behind his 350 in his s10, he was goin home one night and his driveshaft spun out, then he didntjust break his bellhousing in half but he shattered it, pieces all over the road, he said he was driving it like normal but only god knows what he really was doing, now he has a beefed up new th350 and a 383 stroker with nitrous oxide, probs 450-500 hp, the thing is a death trap, especially with him behind the wheel

Grim Reaper · 10-27-2002, 10:14 AM

Might be able to save the tranny. One of the guys over at ColoradoK5.com broke a bellhousing and replaced it.
A lot of Drag racing requires a scatter sheild. Some scatter sheilds you actully cut off the bellhousing and replace it with a stamped steel unit that bolts on at the pump. If you didn't crack the tranny back past the pump then you might look into one of those sheilds to fix your tranny.
Jegs and summit both sell them.

Fred T · 10-27-2002, 11:27 AM

The only reliable way to check your thrust bearing is to setup a dial indicator and measure it. However, since you hammered on the damper, you need to go ahead and replace it, you did damage it. This can be done with the engine still in the truck, your biggest problem will be pulling the oil pan. I would check the end play both before and after replacing the bearing, and be sure the new one is withing the tolerance zone. I have to admit, this is one tranny failure I've never seen.

70shortnphat · 10-27-2002, 04:18 PM

A solid trans mount with rubber motor mounts can do it too.

Adam12 · 10-28-2002, 12:23 AM

well I didn't use a piece of wood and a hammer, I used a rubber mallot so I dont think thats as bad as using a hammer and wood. but still probally damaged the thrust bearing. I didn't have a solid trans mount either, just one I picked up at southern auto. I have ben told to get a polyurathane mount for it, but havent checked into where I can get one. The motor mounts I have are the big block polyurathane mounts from brothers. And the trans didnt just break in half it did shatter and break I have about 6-7 pieces of the bell housing. Thanks for all the help everyone!

Earl Junior · 10-29-2002, 02:06 PM

If your transmission is junk I may be interested in the tailshaft. I bought a TH400 out of a 4x4 and need a few parts. PM me or email me at jbender@lcsc.edu if you're interested in parting out the trans.

chevy2racr · 10-29-2002, 06:43 PM

a friend broke a TH400 in his 80's 2door malibu drag car, its got a$5000 paint job, looks sweet, finally put ladder bars in it, still running 10.5 slick, launched with his 355, wheelled abot 4 foot high, thensnap drive shaft shatterd, ruining his aluminum tunnel work, which sent shock up to the trannyand ripped the tail shaft right off and cracked the bell housing within an inch of clear breaking off
boy was he pissed

10-24-2002, 11:32 PM	#1
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	Has your transmission ever broke in half? Today I went to show my brother that we finaly got my truck running a few weeks ago. I cant go anywhere because I have no driveline but it fires up fine and runs sweet. its a 454 block bored to 481 with a th-400 trans today i fired it up and reved it up a lil then I felt the pedal give and heard the sound of metal falling on the cement. I get out and look under the hood and the motor was sagging bad in the back, so I look under and see that my transmission is nearly upside down! the bell housing on the transmission just broke somehow and chucks of metal were on the ground and tranny fluid was everywhere. anyone know what may have caused this? could it be because there was no driveline installed? oh yeah it ripped the trans mount all up too. I asked around and no one I have talked to has ever seen anything like this.

10-24-2002, 11:41 PM	#4
Hooter My other Love Join Date: Aug 2001 Location: Castlegar B.C. Canada Posts: 4,085	wow no I think you are the first one to ever do that. Gives whole new meaning to "tranny drop" __________________ Castlegar B.C.The great white North (Canada Eh!) Hooter_5@hotmail.com First generation Monte Carlo club pictures of my life

10-24-2002, 11:56 PM	#7
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	So if the motor mounts were the case shouldnt I be able to look at them and see some dmg? or somthing? I havent looked at them closly yet figured id wait til tomorrow to take the rest of the bellhousing off. __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-25-2002, 01:06 AM	#9
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	ok ill check for that tomorrow. __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-25-2002, 05:08 AM	#10
GMCPaul Senior Member Join Date: Mar 2000 Location: Rockville,In. USA Posts: 3,721	Broke 3 of them all attached to the same motor. Talked to a very old and savvy GM mechanic and half way through telling him what happened he says its your thrust bearing in the motor. Well we pulled the motor checked it out, thrust bearing was bad, replaced that bearing, re-installed and never broke a bell housing again. Seems that the crank was walking forward then back and this action broke the housing. How was the bearing damaged? My own stupidity I knocked the harmonic balancer on with a block of wood and hammer rather than using a harmonic balancer installer. What can I say I was only 22 and doing what I had seen done before that worked. Now if they make a tool to do a job I use it as that home method isn't always correct. I Hope its your motor mounts. GMCPaul __________________ Secure Online Catalog for-GMCPauls Truck Parts Email- GMCPAULS@GMAIL.COM

10-24-2002, 11:36 PM	#2
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	Ddddaaamn......nope, i have never broke one in half

10-24-2002, 11:47 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	I've seen one break in 1/2, but it was after a drop onto a cement driveway.

10-24-2002, 11:55 PM	#6
Bowed Registered User Join Date: Oct 2002 Location: where it's hot Posts: 1,059	Faulty or improperly installed motor mounts can break a bell housing.

10-25-2002, 12:19 AM	#8
Bowed Registered User Join Date: Oct 2002 Location: where it's hot Posts: 1,059	Check the motor mounts to see if the motor is moving enough to twist a trans that is bolted to its crossmember and mounts. I had a TH 350 that broke its bell housing on a blazer but on that one the trans was touching the tunnel and was probably getting to much pressure on it when I gunned the truck , which was quite often but other wise I have seen a couple of trucks that broke bell housings just from bad mounts.

10-25-2002, 11:38 AM	#11
yellowgmc Getting cabin fever?!?!?! Join Date: Oct 2002 Location: chisholm, mn Posts: 1,679	i blew up an np231 transfer case at 65mph once. big bang, bigger dent in floorboard. no trannys tho. __________________ Member of the Discs Up Front Club 1972 GMC 1500 1994 F-150 XL 4x4 Tact is for people not whitty enough to be sarcastic

10-25-2002, 11:50 AM	#12
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	No chevy trannys but I new a guy once that had a bad motor mount on his newly installed 302 in a ford. He was cruising along, and went to pass someone, so his transmission kicked down into lower gear. The motor mount broke, and kinked the accel. linkage. Then it broke the bell housing on the transmission. He had to shut the car off at 50 mph. Hosed his entire driveline. He was UPSET. Brand new 302 crate and everything. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

10-25-2002, 02:09 PM	#13
XXL Señor Member Join Date: May 2002 Location: Edge of the world Posts: 5,367	I broke a TH400 bellhousing in two right at the point where it curves into the main body of the transmission. The driver's side motor mount broke on my dual-quad 454 and I thought I was going to fil the truck over on it's side with all the torque that was going on. I also broke the distributor when it hit the firewall. Kenneth __________________ Craigslist \| ebay \| Engrishtees \| www.myattitudesucks.com \| Follow me on Twitter

10-25-2002, 03:05 PM	#14
Maximum Overdrive December 21, 2012 Join Date: Apr 2000 Location: Black Eagle, Montana Posts: 1,634	Had one break after I snapped my driveline in two doing about 80 down the interstate. It busted the rear of the tailshaft off and snapped it off from the motor around the bell housing. The busted driveline put about a 6 inch high dent into the floorboard of the cab. Thought a damn bomb went off when the driveline came up into the cab like that. lol __________________ *"!Ama Sua, Ama Kjella, Ama Lllulla!"*

10-25-2002, 03:16 PM	#15
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	Oh man! I used a block of wood and a hammer to put the harmonic balancer on! this sucks! __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-26-2002, 07:01 PM	#16
chewed 71'er Registered User Join Date: Mar 2002 Location: KC, NW Missouri Posts: 144	Man alive!! What an ugly lesson in shade-tree mechanics! Guess we need to leave wood blocks and hammers for ford (gag) products.



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10-26-2002, 07:24 PM	#17
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	Adam 12, if you did by chance "mangle the thrust bearing you should be able to feel it as excessive end play in the crank. on a fresh eng you will have in the range of .005 end play. You need to take the belts off to 'feel this". at .005 end play, you probably wont be able to feel any movement , due to oil around the thrust faces of the bearing. I have run some engines with more than ideal clearance, & as long as the counter weights on the crank werent "kissin a mainweb" there wasnt too much problem. take hold of the balancer, & try pushin it back /forth. If you feel quite a bit of movement, you have problems & should check it out. If it feels tight, you might check converter to pump clearance... should be in the range of .1875(3/16), or look for a warped flex plate. more than likely the flex plate is fubar from the grenade, & you wont be able to check clearance till you put another trans in, but as it bolts up there should be a little clearance tween the flexplate & converter( no less than 1/8", & no more than 1/4). Good luck......crazy AL

10-26-2002, 07:41 PM	#18
Grim Reaper Registered User Join Date: Jul 2001 Location: Atlanta GA Posts: 1,704	Well no driveshaft on the tranny seems to me that unless is was a fixed yoke TH400 that you may not have had any fluid in the tranny. Might have seized the torque converter to the pump if that were the case. __________________ Grim-Reaper 70 Pontiac LeMans Sport Convertible, worlds longest resto in progress Looking for 71-72 2wd Blazer or Jimmy Project

10-26-2002, 08:24 PM	#19
67cst i love summertime Join Date: Jul 2002 Location: Kelowna BC Posts: 4,303	yep my buddy had a th350 behind his 350 in his s10, he was goin home one night and his driveshaft spun out, then he didntjust break his bellhousing in half but he shattered it, pieces all over the road, he said he was driving it like normal but only god knows what he really was doing, now he has a beefed up new th350 and a 383 stroker with nitrous oxide, probs 450-500 hp, the thing is a death trap, especially with him behind the wheel __________________ 1967 shortbox stepside Chevy, 365 hp 327, th400. GLOVE BOX LIGHTS FORSALE, click link for info http://67-72chevytrucks.com/vboard/s...d.php?t=273724

10-27-2002, 10:14 AM	#20
Grim Reaper Registered User Join Date: Jul 2001 Location: Atlanta GA Posts: 1,704	Might be able to save the tranny. One of the guys over at ColoradoK5.com broke a bellhousing and replaced it. A lot of Drag racing requires a scatter sheild. Some scatter sheilds you actully cut off the bellhousing and replace it with a stamped steel unit that bolts on at the pump. If you didn't crack the tranny back past the pump then you might look into one of those sheilds to fix your tranny. Jegs and summit both sell them. __________________ Grim-Reaper 70 Pontiac LeMans Sport Convertible, worlds longest resto in progress Looking for 71-72 2wd Blazer or Jimmy Project

10-27-2002, 11:27 AM	#21
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	The only reliable way to check your thrust bearing is to setup a dial indicator and measure it. However, since you hammered on the damper, you need to go ahead and replace it, you did damage it. This can be done with the engine still in the truck, your biggest problem will be pulling the oil pan. I would check the end play both before and after replacing the bearing, and be sure the new one is withing the tolerance zone. I have to admit, this is one tranny failure I've never seen. __________________ Fred There is no such thing as too much cam...just not enough engine.

10-27-2002, 04:18 PM	#22
70shortnphat "See the U.S.A....." Join Date: Apr 2002 Location: Richmond TX. Posts: 269	A solid trans mount with rubber motor mounts can do it too. __________________ 1970 short bed fleetside 1949 all origional chevy 3600 1974 camaro Richmond , Texas(just S.W.of Houston)

10-28-2002, 12:23 AM	#23
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	well I didn't use a piece of wood and a hammer, I used a rubber mallot so I dont think thats as bad as using a hammer and wood. but still probally damaged the thrust bearing. I didn't have a solid trans mount either, just one I picked up at southern auto. I have ben told to get a polyurathane mount for it, but havent checked into where I can get one. The motor mounts I have are the big block polyurathane mounts from brothers. And the trans didnt just break in half it did shatter and break I have about 6-7 pieces of the bell housing. Thanks for all the help everyone! __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-29-2002, 02:06 PM	#24
Earl Junior Cadillac power Join Date: Oct 2002 Location: North Idaho Posts: 296	If your transmission is junk I may be interested in the tailshaft. I bought a TH400 out of a 4x4 and need a few parts. PM me or email me at jbender@lcsc.edu if you're interested in parting out the trans. __________________ Just for the record, if I'm down to my last potato, I'm not sharing it with a guy who wants to kill me so he can get a better supply of virgins in paradise. That lesson is a little thing I call Economics 101, infidel style. --Scott Adams author of Dilbert

10-29-2002, 06:43 PM	#25
chevy2racr So Many Ideas, So Little Money Join Date: Sep 2001 Location: Marshalltown, IA Posts: 1,610	a friend broke a TH400 in his 80's 2door malibu drag car, its got a$5000 paint job, looks sweet, finally put ladder bars in it, still running 10.5 slick, launched with his 355, wheelled abot 4 foot high, thensnap drive shaft shatterd, ruining his aluminum tunnel work, which sent shock up to the trannyand ripped the tail shaft right off and cracked the bell housing within an inch of clear breaking off boy was he pissed __________________ 72 Blazer 3/4 ton running gear 4.10s NP205/TH350 350 4in lift half doors 71 C10 with 454 99 S-10 5.1L SBC 700R4 09 Malibu Marshalltown, Iowa

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