The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Need ideas. 15yr old vibration that just won't go away

Tom · 02-05-2021, 04:53 PM

I bought my 98 back in 2006 with 75k miles on it. Had a slight shudder when the torque convertor stalled [1400rpm ish] when accelerating from a stop. Since then I've:
-cut and balanced driveshaft
-new u joints
-replaced entire rear axle
-rebuilt transmission
-new torque convertor
-replaced all engine and trans mounts
-inspected flexplate for cracks while trans was out
-multiple sets of tires and different set of rims
-harmonic balancer

Nothing has stopped it. It got much worse after the trans swap from flexing the motor mounts. Just finished changing them, and the vibration is back to when I bought it level of annoying. WTF??? What else can I check???
Vibration isn't there once the truck is moving. Its only when starting off from a stop. It isn't there once the rpm's are over 1500 in 1st either. Its almost like running over a rumble strip. I'm lost.

02-05-2021, 04:53 PM	#1
Tom driving is in my blood Join Date: Dec 1999 Location: Mesa AZ Posts: 5,692	Need ideas. 15yr old vibration that just won't go away I bought my 98 back in 2006 with 75k miles on it. Had a slight shudder when the torque convertor stalled [1400rpm ish] when accelerating from a stop. Since then I've: -cut and balanced driveshaft -new u joints -replaced entire rear axle -rebuilt transmission -new torque convertor -replaced all engine and trans mounts -inspected flexplate for cracks while trans was out -multiple sets of tires and different set of rims -harmonic balancer Nothing has stopped it. It got much worse after the trans swap from flexing the motor mounts. Just finished changing them, and the vibration is back to when I bought it level of annoying. WTF??? What else can I check??? Vibration isn't there once the truck is moving. Its only when starting off from a stop. It isn't there once the rpm's are over 1500 in 1st either. Its almost like running over a rumble strip. I'm lost. __________________ -78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me.