Probably a Stupid Question, But... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

MDC · 01-23-2009, 06:48 AM

Changing a 3OTT to a TH350. Can I use the same flywheel and bellhousing bolts?

petey-pablo · 01-23-2009, 06:52 AM

Theres Never a Stupid Question thats what we are all here for to share Knoledge...Someone will will help you, Sorry I dont have the anwer this is the first I heard of a 3OTT What is it a Transmission I supose we learn something new every day...

windmill · 01-23-2009, 07:08 AM

you will have to cut the manual trans member out and get a auto crossmember. they can found in the parts for sale, or buy an after market one. you cannot use the manual flywheel, you will have to get a automatic one also the flywheel bolts too. you can use the bellhousing bolts tho. I'm thinking you will have to change the starter too but not for sure.

eightbanger · 01-23-2009, 07:09 AM

Is that short for "3 on the tree"?

MDC · 01-23-2009, 08:09 AM

Yea 3 on the tree.
I have all the parts. x member changed, new starter nose, new rad w/cooler tilt auto column and everything else ready to go back in Just need to know if I can use the bolts.

petey-pablo · 01-23-2009, 08:27 AM

Quote:

Originally Posted by eightbanger

Is that short for "3 on the tree"?

Oh I get it now

Why didn't I think ot that My Bad... Just like windmill says you can find most if not all the parts requierd for the change on the Parts For Sale Board forum Thats what my truck origanaly had It was wierd to drive Now much better and Faster

from a 6 OTT to 8 atomatic....Id go with stock used parts you cant go wrong they were made for our trucks you never know with aftermarket parts if they will fit or not something can be off just alittle and it ruiens your whole day.......

*MonteSS454* · 01-23-2009, 10:09 AM

6OTT would suck, and I wanna see this 8 speed automatic Petey.

6772owner · 01-23-2009, 10:15 AM

I think he meant 6 cyl 3 on the the three to V8 auto LOL

MDC · 01-23-2009, 03:30 PM

So does anyone know if the bolts will work?

Indyuke · 01-23-2009, 03:38 PM

MDC. I don't think you can reuse the flywheel bolts because an auto transmission actually doesn't have a flywheel, it has a flexplate. Besides, if you could reuse those bolts, why would you? A lot of torque goes right through those bolts, they're the only thing holding the flexplate to the crank... I would get new ones.

As for the bellhousing bolts, if the shank or the body is the right length, I would definately reuse them. They don't go through the strain that the flexplate or flywheel bolts go through. I hope this helps.

pickupman · 01-23-2009, 06:19 PM

I believe one bolt is course thread and one fine for auto

Tx Firefighter · 01-23-2009, 08:54 PM

The flywheel bolts will not work with the automatic trans flexplate. The auto flexplate is much thinner than the old flywheel was and therefore take correspondingly shorter bolts. They are usually available in a pack at most any parts store in the high performance chrome crap aisle.

MDC · 01-23-2009, 11:55 PM

Thanks Kevin, how's that dually comming?

Pickupman, surely the threads aren't different, that would mean changing the crankshaft. I better go check

Tx Firefighter · 01-24-2009, 07:42 AM

Quote:

Originally Posted by MDC

Thanks Kevin, how's that dually comming?

Pickupman, surely the threads aren't different, that would mean changing the crankshaft. I better go check

First, theads in the crankshaft are fine thread. The bolts being as short as they are and fine thread, you usually wind up having to buy the prepackaged flexplate bolts at the auto parts store rather than just getting grade 8s at the hardware.

The bellhousing bolts are just normal corse thread 3/8 bolts.

As far as the dually, I am working on it a bit at a time. I've just cut the money tree off pretty short getting this powdercoating operation up and running. Hopefully in a week after my ebay auctions end I will be flush enough with cash to work on it some more. Hopefully in a short while, the powdercoating will pay for itself and start to generate an income.

**WIDESIDE72** · 01-24-2009, 10:36 AM

No difference in the cranks. All are fine thread. Auto bolts are shorter than manual. Bellhousing bolts should be the same.

BTW, there is a locating pin on the crank that takes most of the torque, not the bolts. The bolts hold some torque, but not all. I have never heard of flywheel bolts failing. Usually the first failure will be the flex plate will crack around the bolt holes. I had this happen on a 79 Malibu with a torque monster (LOL) 267 V8! I never knew it til I pulled the 267 to swap a 383 in.

lowriden58 · 01-24-2009, 11:18 AM

Quote:

Originally Posted by WIDESIDE72

No difference in the cranks.

thats not what she said

sorry this head cold is making me feel funny

01-23-2009, 06:48 AM	#1
MDC Registered User Join Date: Oct 2005 Location: N Texas Posts: 727	Probably a Stupid Question, But... Changing a 3OTT to a TH350. Can I use the same flywheel and bellhousing bolts? __________________ 67 C10 Shortbed 327 05 F150 4x4 NO APPOLOGIES 's 02 Xpress X19 02 Yamaha VMax 150 www.xpressboats.com Nothing says 'poor craftmanship' like wrinkles in your duct tape

01-23-2009, 06:52 AM	#2
petey-pablo "THE GREEN GOBLIN" Join Date: Mar 2008 Location: Fremont Ca. Posts: 1,025	Re: Probably a Stupid Question, But... Theres Never a Stupid Question thats what we are all here for to share Knoledge...Someone will will help you, Sorry I dont have the anwer this is the first I heard of a 3OTT What is it a Transmission I supose we learn something new every day... __________________ Petey-pablo "THE GREEN GOBLIN" 1972 Cheyenne 10 Short Fleet Side Front 2.5inch Spindles with 2inch Springs Rear 4inch drop Springs. 454BBC TH400,Posi 1971 Cheyenne 10 Long Fleet Side 454BBC TH350,Posi Sold Drive it like you stole it! Petey-pablo@sbcglobal.net

01-23-2009, 07:08 AM	#3
windmill Registered User Join Date: Jan 2007 Location: Sylvania, Alabama Posts: 288	Re: Probably a Stupid Question, But... you will have to cut the manual trans member out and get a auto crossmember. they can found in the parts for sale, or buy an after market one. you cannot use the manual flywheel, you will have to get a automatic one also the flywheel bolts too. you can use the bellhousing bolts tho. I'm thinking you will have to change the starter too but not for sure. __________________ 72 swb pickup http://i124.photobucket.com/albums/p...k/100_0958.jpg 1967 chevelle ss 1966 mustang getting a l33 ls motor 1969 chevy dump truck 1989 mustang 6.0 ls best time of 1.29 at 5.91 https://www.youtube.com/watch?v=JtbooZoGZmQ Last edited by windmill; 01-23-2009 at 07:09 AM.

01-23-2009, 07:09 AM	#4
eightbanger 454 MAKES IT ROAR Join Date: Jan 2008 Location: Essex, U.K Posts: 2,701	Re: Probably a Stupid Question, But... Is that short for "3 on the tree"? __________________ Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger

01-23-2009, 08:09 AM	#5
MDC Registered User Join Date: Oct 2005 Location: N Texas Posts: 727	Re: Probably a Stupid Question, But... Yea 3 on the tree. I have all the parts. x member changed, new starter nose, new rad w/cooler tilt auto column and everything else ready to go back in Just need to know if I can use the bolts. __________________ 67 C10 Shortbed 327 05 F150 4x4 NO APPOLOGIES 's 02 Xpress X19 02 Yamaha VMax 150 www.xpressboats.com Nothing says 'poor craftmanship' like wrinkles in your duct tape

01-23-2009, 10:09 AM	#7
MonteSS454 Account Suspended Join Date: Jun 2007 Location: Claremore, Oklahoma Posts: 821	Re: Probably a Stupid Question, But... 6OTT would suck, and I wanna see this 8 speed automatic Petey. Last edited by MonteSS454; 01-23-2009 at 10:09 AM.

01-23-2009, 10:15 AM	#8
6772owner Gearhead Join Date: Jan 2008 Location: Colorado Posts: 1,193	Re: Probably a Stupid Question, But... I think he meant 6 cyl 3 on the the three to V8 auto LOL __________________ 2002 Saturn SL2, My D/D 2019 Ford Fusion SE, Ecoboost - Wife's D/D 1993 Camaro Z28, A4, CAI, Cat-Back Exhaust Project C10 (my 72' C10 w/96' LT1, 700R4, bagged F&R, 18's (for now), Short/Fleet) -- SOLD! Build Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=313644

01-23-2009, 03:30 PM	#9
MDC Registered User Join Date: Oct 2005 Location: N Texas Posts: 727	Re: Probably a Stupid Question, But... So does anyone know if the bolts will work? __________________ 67 C10 Shortbed 327 05 F150 4x4 NO APPOLOGIES 's 02 Xpress X19 02 Yamaha VMax 150 www.xpressboats.com Nothing says 'poor craftmanship' like wrinkles in your duct tape

01-23-2009, 03:38 PM	#10
Indyuke Registered User Join Date: Feb 2008 Location: Lake Stevens, WA Posts: 623	Re: Probably a Stupid Question, But... MDC. I don't think you can reuse the flywheel bolts because an auto transmission actually doesn't have a flywheel, it has a flexplate. Besides, if you could reuse those bolts, why would you? A lot of torque goes right through those bolts, they're the only thing holding the flexplate to the crank... I would get new ones. As for the bellhousing bolts, if the shank or the body is the right length, I would definately reuse them. They don't go through the strain that the flexplate or flywheel bolts go through. I hope this helps.

01-23-2009, 06:19 PM	#11
pickupman Registered User Join Date: Dec 2000 Location: Greeneville, TN Posts: 3,097	Re: Probably a Stupid Question, But... I believe one bolt is course thread and one fine for auto __________________ atheystruck@comcast.net 67 1/2 ton 4wd custom cab 72 1/2 ton 4wd super cheyenne 71 1/2 BB super cheyenne shortbed

01-23-2009, 08:54 PM	#12
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Re: Probably a Stupid Question, But... The flywheel bolts will not work with the automatic trans flexplate. The auto flexplate is much thinner than the old flywheel was and therefore take correspondingly shorter bolts. They are usually available in a pack at most any parts store in the high performance chrome crap aisle. __________________ I'm on the Instagram- @Gearhead_Kevin

01-23-2009, 11:55 PM	#13
MDC Registered User Join Date: Oct 2005 Location: N Texas Posts: 727	Re: Probably a Stupid Question, But... Thanks Kevin, how's that dually comming? Pickupman, surely the threads aren't different, that would mean changing the crankshaft. I better go check __________________ 67 C10 Shortbed 327 05 F150 4x4 NO APPOLOGIES 's 02 Xpress X19 02 Yamaha VMax 150 www.xpressboats.com Nothing says 'poor craftmanship' like wrinkles in your duct tape

01-24-2009, 10:36 AM	#15
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,500	Re: Probably a Stupid Question, But... No difference in the cranks. All are fine thread. Auto bolts are shorter than manual. Bellhousing bolts should be the same. BTW, there is a locating pin on the crank that takes most of the torque, not the bolts. The bolts hold some torque, but not all. I have never heard of flywheel bolts failing. Usually the first failure will be the flex plate will crack around the bolt holes. I had this happen on a 79 Malibu with a torque monster (LOL) 267 V8! I never knew it til I pulled the 267 to swap a 383 in.



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