engine/tranny angle relative to rear diff.? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BUXMAN66 · 08-07-2004, 12:57 AM

been doing a build up on a '49 gmc 1/2 t. shrtbd 350/350 combo. tranny crossmember (6"drop) from jim carter classic truck parts. got everything finished up 'cept for some last minor details on the engine (hoses,belts...etc.) noticed the angle from the output shaft on trans into the forward u-joint was off.... i placed my magnetic angle finder on my intake (no carb. mounted yet) and my engine was on a 3 deg.negative angle.(below the crank center-line) so in other words my tranny out-put shaft is at a pretty low angle. i can machine some spacers to go between the tranny x-member and the inner frame rail where it bolts at, thus bringing up the out-put shaft angle....but what is the optimum angle needed at the intake/ carb. base ....? thanks for any replies! p.s. it's a real p.i.t.a. undoing other people's screw-up's!! previous owner's "angle iron" tranny x-member nesessitated this whole job. he had a approx. 6" drop from bottom of frame to the tranny mount rubber.....and thus the pinion angle was set for this. hopefully going to a "safe" tubular x-member w/ a 6" drop, i'll still be able to keep the pinion angle the same.

rico_bob · 08-07-2004, 01:13 PM

The carb plate or intake manifold should be near to level as you can make it.
The output shaft angle should be about 2-4 percent down from level on the angle finder. the rear axle should be pointing "up" on a 2-5 percent angle. Try to match the output and input if you can. My two cents worth. rico_bob

www.ricos-rods-and-relics.com

BUXMAN66 · 08-07-2004, 03:08 PM

thanks rico, will be going out to the farm tomorrow to do just that!!

BUXMAN66 · 08-07-2004, 03:09 PM

oh, yeah...and i hate zero posts/replies too!! thanks for your reply...

rico_bob · 08-08-2004, 01:55 PM

Glad I can help out! If you need any parts check out my web site for them. www.ricos-rods-and-relics.com

rico_bob

solidaxel · 08-08-2004, 07:01 PM

I think I would put the angle finder on the valve cover rail or the oil pan rail to establish my readings as they are the same plane as the crankshaft, transmission angle, and tell me what the reading is there!

rico_bob · 08-08-2004, 09:46 PM

That would be OK... But remeber I said you want the carb plate to be near "0" (or level). The best place to check the angle is on the end of the tail shaft of the transmission (get closer to the source I always say). rico_bob

tommo · 09-25-2004, 04:22 AM

the output of the trans and the pinion shaft in the rear end should be parallel to within 2 degrees or u joints will not last long. if that alignment is very far off, count on vibration, and driveshafts may fail!

denny03830 · 10-04-2004, 02:07 PM

The rear axle pinion and the transmission spline should be parallel. If the transmission spline is down by 3 degrees the rear axle pinion offset the same 3 degrees. You can also drop the pinion about 2 degrees more than the transmission, which makes the assumption that the torque of the engine will pull the pinion up about 2 degrees under power so the final angle will be back to parallel. The engine should not be level, if you put a angle finder on the valve covers the engine should slope down towards the firewall about 3 to 5 degrees.

08-07-2004, 12:57 AM	#1
BUXMAN66 go bucks! Join Date: Jan 2002 Location: MIAMISBURG OHIO USA Posts: 803	engine/tranny angle relative to rear diff.? been doing a build up on a '49 gmc 1/2 t. shrtbd 350/350 combo. tranny crossmember (6"drop) from jim carter classic truck parts. got everything finished up 'cept for some last minor details on the engine (hoses,belts...etc.) noticed the angle from the output shaft on trans into the forward u-joint was off.... i placed my magnetic angle finder on my intake (no carb. mounted yet) and my engine was on a 3 deg.negative angle.(below the crank center-line) so in other words my tranny out-put shaft is at a pretty low angle. i can machine some spacers to go between the tranny x-member and the inner frame rail where it bolts at, thus bringing up the out-put shaft angle....but what is the optimum angle needed at the intake/ carb. base ....? thanks for any replies! p.s. it's a real p.i.t.a. undoing other people's screw-up's!! previous owner's "angle iron" tranny x-member nesessitated this whole job. he had a approx. 6" drop from bottom of frame to the tranny mount rubber.....and thus the pinion angle was set for this. hopefully going to a "safe" tubular x-member w/ a 6" drop, i'll still be able to keep the pinion angle the same. __________________ '68 swb 1/2t 350/350th '86 lngbd 3/4 TON parts getter '49 gmc 1/2 t 5 window 350/350th '96 gmc sonoma sle ext-cab. hey it's a 4cyl. 5 spd and good on gas y'know?

08-07-2004, 01:13 PM	#2
rico_bob "Treasure the Ride" Join Date: Nov 2001 Location: Mid Michigan, Harrison Michigan, USA Posts: 682	I hate ZEROS (unanswered posts) The carb plate or intake manifold should be near to level as you can make it. The output shaft angle should be about 2-4 percent down from level on the angle finder. the rear axle should be pointing "up" on a 2-5 percent angle. Try to match the output and input if you can. My two cents worth. rico_bob www.ricos-rods-and-relics.com __________________ If you think you can you're right. If you think you can't you're still right. Trucks: '56 SWB; '57 SWB; '63 C-10 Current projects: 1963 Long Fleetside for the wife! '56 for the daughter. Visit us at: www.ricos-rods-and-relics.com

08-07-2004, 03:08 PM	#3
BUXMAN66 go bucks! Join Date: Jan 2002 Location: MIAMISBURG OHIO USA Posts: 803	thanks rico, will be going out to the farm tomorrow to do just that!! __________________ '68 swb 1/2t 350/350th '86 lngbd 3/4 TON parts getter '49 gmc 1/2 t 5 window 350/350th '96 gmc sonoma sle ext-cab. hey it's a 4cyl. 5 spd and good on gas y'know?

08-08-2004, 01:55 PM	#5
rico_bob "Treasure the Ride" Join Date: Nov 2001 Location: Mid Michigan, Harrison Michigan, USA Posts: 682	Glad to be of assistance! *Glad I can help out! If you need any parts check out my web site for them. www.ricos-rods-and-relics.com* rico_bob __________________ If you think you can you're right. If you think you can't you're still right. Trucks: '56 SWB; '57 SWB; '63 C-10 Current projects: 1963 Long Fleetside for the wife! '56 for the daughter. Visit us at: www.ricos-rods-and-relics.com

08-08-2004, 07:01 PM	#6
solidaxel Registered User Join Date: Dec 2002 Location: Cactus Patch So. Az Posts: 4,749	I think I would put the angle finder on the valve cover rail or the oil pan rail to establish my readings as they are the same plane as the crankshaft, transmission angle, and tell me what the reading is there! __________________ 53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD) 53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25 55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73 62 Solidaxle Corvette Roman Red (327 340hp 4spd 3:36) C4 & C5 suspension tube chassis LS 3 4L70E 65 Corvette Coupe 327 350hp 4spd 4:11 78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42 2000 S-Type 3.0 (wife cruiser) 2003 GMC SCSB 5.3 4L60E 3:42

08-07-2004, 03:09 PM	#4
BUXMAN66 go bucks! Join Date: Jan 2002 Location: MIAMISBURG OHIO USA Posts: 803	oh, yeah...and i hate zero posts/replies too!! thanks for your reply...

08-08-2004, 09:46 PM	#7
rico_bob "Treasure the Ride" Join Date: Nov 2001 Location: Mid Michigan, Harrison Michigan, USA Posts: 682	True...however... That would be OK... But remeber I said you want the carb plate to be near "0" (or level). The best place to check the angle is on the end of the tail shaft of the transmission (get closer to the source I always say). rico_bob __________________ If you think you can you're right. If you think you can't you're still right. Trucks: '56 SWB; '57 SWB; '63 C-10 Current projects: 1963 Long Fleetside for the wife! '56 for the daughter. Visit us at: www.ricos-rods-and-relics.com

09-25-2004, 04:22 AM	#8
tommo Junior Member Join Date: Sep 2004 Location: redwood city california Posts: 41	the output of the trans and the pinion shaft in the rear end should be parallel to within 2 degrees or u joints will not last long. if that alignment is very far off, count on vibration, and driveshafts may fail!

10-04-2004, 02:07 PM	#9
denny03830 Registered User Join Date: Oct 2004 Posts: 1	Should be parallel. The rear axle pinion and the transmission spline should be parallel. If the transmission spline is down by 3 degrees the rear axle pinion offset the same 3 degrees. You can also drop the pinion about 2 degrees more than the transmission, which makes the assumption that the torque of the engine will pull the pinion up about 2 degrees under power so the final angle will be back to parallel. The engine should not be level, if you put a angle finder on the valve covers the engine should slope down towards the firewall about 3 to 5 degrees.



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