Missing rear tranny cross member??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BaroneDog · 12-06-2016, 01:58 PM

Hoping someone out there can help answer this question: Should there be a rear tranny cross member support on a 4 speed muncie in a 1967 stepside? I started stripping the motor down to pull it with the tranny and noticed that the tranny was only supported by means of the bell housing (tranny bolted to bell housing and bell housing supported by cross member). This is my first manual tranny 67-72 truck, so not sure what to expect. Seems like the tranny would be better served with additional support in the rear. See attached photo of current setup. Thanks in advance for any advice!

GASoline71 · 12-06-2016, 03:10 PM

Supported at the bell housing from the frame. Transmission just hangs there.

Gary

**Captainfab** · 12-07-2016, 12:18 AM

It is just fine as it is. That is no different than the SM420 that was in there originally.

BaroneDog · 12-10-2016, 10:10 PM

Thanks for the confirmation. Still seems strange to me just seeing the rear of the tranny just hanging out in the breeze, but I guess that is how they do it in this application. I am swapping the motor out from the 327 that was in there to a 383 with about 400 HP and ft-lbs. Hope the extra torque does not strain that setup too much and break something. Does anyone ever fab a second rear crossmember to reinforce and support higher power/toque applications?

**Captainfab** · 12-11-2016, 12:35 AM

Adding a third crossmember could do more harm than good by creating a stress/binding situation. If you are worried about it, remove the bellhousing crossmember and install a trans crossmember.

crazy longhorn · 12-11-2016, 08:31 PM

Agree with Fab man (Captain)......You dont need , or want the 3rd mount......I ran several M-21 muncie 's, hanging on that bell. I did not break one of them

Longhorn

BaroneDog · 12-12-2016, 09:32 PM

Great, thanks for the confirmation. I will now try to focus on deciding which type of engine I want to pair with the tranny. Everytime I think I decide, then I change my mind!

crazy longhorn · 12-12-2016, 10:29 PM

One thing that I will add....it wont be a problem on the 67 bell, but the center hole size changes, in the 68 yr. IIRC, 4 11/16, vs 5 1/8 inches. If you have the later bell, you can have a machined ring pressed onto the front bearing retainer......it should be a snug fit (.002), on the fit on the center hole, on the bell. Longhorn

12-06-2016, 01:58 PM	#1
BaroneDog Registered User Join Date: Dec 2016 Location: Lexington, MA Posts: 92	Missing rear tranny cross member??? Hoping someone out there can help answer this question: Should there be a rear tranny cross member support on a 4 speed muncie in a 1967 stepside? I started stripping the motor down to pull it with the tranny and noticed that the tranny was only supported by means of the bell housing (tranny bolted to bell housing and bell housing supported by cross member). This is my first manual tranny 67-72 truck, so not sure what to expect. Seems like the tranny would be better served with additional support in the rear. See attached photo of current setup. Thanks in advance for any advice! Attached Images

12-07-2016, 12:18 AM	#3
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: Missing rear tranny cross member??? It is just fine as it is. That is no different than the SM420 that was in there originally. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

12-10-2016, 10:10 PM	#4
BaroneDog Registered User Join Date: Dec 2016 Location: Lexington, MA Posts: 92	Re: Missing rear tranny cross member??? Thanks for the confirmation. Still seems strange to me just seeing the rear of the tranny just hanging out in the breeze, but I guess that is how they do it in this application. I am swapping the motor out from the 327 that was in there to a 383 with about 400 HP and ft-lbs. Hope the extra torque does not strain that setup too much and break something. Does anyone ever fab a second rear crossmember to reinforce and support higher power/toque applications?

12-11-2016, 12:35 AM	#5
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: Missing rear tranny cross member??? Adding a third crossmember could do more harm than good by creating a stress/binding situation. If you are worried about it, remove the bellhousing crossmember and install a trans crossmember. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

12-11-2016, 08:31 PM	#6
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Re: Missing rear tranny cross member??? Agree with Fab man (Captain)......You dont need , or want the 3rd mount......I ran several M-21 muncie 's, hanging on that bell. I did not break one of them Longhorn __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears.... Last edited by crazy longhorn; 12-11-2016 at 08:33 PM. Reason: missed word

12-12-2016, 09:32 PM	#7
BaroneDog Registered User Join Date: Dec 2016 Location: Lexington, MA Posts: 92	Re: Missing rear tranny cross member??? Great, thanks for the confirmation. I will now try to focus on deciding which type of engine I want to pair with the tranny. Everytime I think I decide, then I change my mind!

12-12-2016, 10:29 PM	#8
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Re: Missing rear tranny cross member??? One thing that I will add....it wont be a problem on the 67 bell, but the center hole size changes, in the 68 yr. IIRC, 4 11/16, vs 5 1/8 inches. If you have the later bell, you can have a machined ring pressed onto the front bearing retainer......it should be a snug fit (.002), on the fit on the center hole, on the bell. Longhorn __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....



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