1998 350 Chevy Tahoe - Vibration Issue

[Barry b]

I have modified our 1998 LT K1500 Tahoe by:
- Lifting it 6"
- Placing it on 20" Fuel wheels with 35"x12" K02 tires
- Replaced the diff with a 14 bolt and heaver axel with an ABS air locker
- Replaced the rear drive shaft
- Replaced the running boards with N-fab tubes
- Replaced the front and rear bumpers with Iron Cross bumper with a 12000 lb. winch
- Replaced the roof rack with a Rhino Rack platform and changed the side mirrors with towing mirrors
- Replaced the air intake with a cold air KN filter and box
- Added a 1" throttle body spacer
- Replaced the mechanical fan, clutch, and heat sink with electric fans
- Replaced the stock manifold, cats, and exhaust with long headers, new cats, and an 18" magna-flow muffler and exhaust
- Replaced head, parking, and tail lights with LEDs, added driving, and fog LED light, and other assorted superficial options

BUT I have a persistent vibration that increases and is worst at around 65 mph (is worse when towing). I have had the wheels and drive shaft balanced, and it has been suggested that the issue is a bent/warped torque converter.

Has anyone else experienced this issue and if so what did you do?

Thanks you in advance
bb.

 

[Eman85]

Bent torque converter? That's a new one on me. I'd be checking pinion angle and u-joint working angles first.

 

[OR VietVet]

Tires contributing to the vibes. Show tread pics. Pinion angle is contributing, show pics. Replaced driveshaft with what? Condition of all mounts? Front cv axles mods?

 

[east302]

Have you rotated the tires?

 

[Barry b]

Have you rotated the tires?

Yes, in fact bought new tires ... thnx for the question bb.