drop block rear suspension question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Blackhawkdc · 07-01-2004, 09:43 PM

Hey all, I'm sure there are plenty of you that have done the simple 2" drop on the rear axle using the aluminum axle spacers. Have any of you ran in to issues with pinion angles? Just trying to diagnose my truck and the odd vibration I get at freeway speeds, 65-75mph. The u-joint angles just seem a little off to me, not equal. Anyone else run in to this issue before? If so, how'd you correct it? I have a 350/400 combo in the truck with an aftermarket trans crossmember. Thanks!

Tx Firefighter · 07-01-2004, 09:50 PM

I've run many thousands of miles in trucks with the 2 inch blocks in the back with no vibrations.

Do you have fresh U-joints? If you have a carrier bearing, is it in good shape?

Blackhawkdc · 07-05-2004, 11:41 PM

I have brand new u-joints front and rear, complete new driveshaft. No carrier bearing, its a one piece. Its a weird vibration, like there are harmonics out of whack.

crazy longhorn · 07-06-2004, 12:05 AM

I wouldnt think a straight 2" drop on a block would cause any problems. here is something to try(if you havent already).....unbolt the shaft from the diff, & flip the u joint 180 over on the yolk & bolt it back up. Some times that is enough to cure a vibe on a shaft that the balance is good on. Best of luck,crazyL

07-01-2004, 09:43 PM	#1
Blackhawkdc 440 american Horses Join Date: Mar 2001 Location: Anoka, MN USA Posts: 470	drop block rear suspension question Hey all, I'm sure there are plenty of you that have done the simple 2" drop on the rear axle using the aluminum axle spacers. Have any of you ran in to issues with pinion angles? Just trying to diagnose my truck and the odd vibration I get at freeway speeds, 65-75mph. The u-joint angles just seem a little off to me, not equal. Anyone else run in to this issue before? If so, how'd you correct it? I have a 350/400 combo in the truck with an aftermarket trans crossmember. Thanks! __________________ Seth Petro 1969 Chev Short Step 425hp 350, TH400, big tires, fast truck 1979 Pontiac Trans Am 1991 Saturn SL1 - gas mileage! (and free) 1977 Buick LeSabre - for sale May America bless God, and may God bless America

07-01-2004, 09:50 PM	#2
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	I've run many thousands of miles in trucks with the 2 inch blocks in the back with no vibrations. Do you have fresh U-joints? If you have a carrier bearing, is it in good shape? __________________ I'm on the Instagram- @Gearhead_Kevin

07-05-2004, 11:41 PM	#3
Blackhawkdc 440 american Horses Join Date: Mar 2001 Location: Anoka, MN USA Posts: 470	I have brand new u-joints front and rear, complete new driveshaft. No carrier bearing, its a one piece. Its a weird vibration, like there are harmonics out of whack. __________________ Seth Petro 1969 Chev Short Step 425hp 350, TH400, big tires, fast truck 1979 Pontiac Trans Am 1991 Saturn SL1 - gas mileage! (and free) 1977 Buick LeSabre - for sale May America bless God, and may God bless America

07-06-2004, 12:05 AM	#4
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	I wouldnt think a straight 2" drop on a block would cause any problems. here is something to try(if you havent already).....unbolt the shaft from the diff, & flip the u joint 180 over on the yolk & bolt it back up. Some times that is enough to cure a vibe on a shaft that the balance is good on. Best of luck,crazyL __________________ 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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