Driveline Vibrations Even With a Rear CV

[BIOHZDK5]

So I have this vibration at 30 to 35 mph. Goes away on the hwy but is really bad on residential streets. I have search and most of what I have found is when you do not have a rear CV. I have a rear CV so I am at the glorious K5 brick wall.

Specs:
350 motor, 350 tranny, 203 full time (no PT kit) , 4" lift- springs in the front block and AAL in the back, 33x10.50 TSL radials. Its a mall crawler I know!

Whats New:

New front drive shaft with CV
New rear drive shaft with CV
New T case mounts (Energy Susp. Poly)
New motor mounts-Autozone nothing fancy.

Could it be the pinion angle?? I'm not sure it is, as the vibs seem to be at the front of t case? Could it be the t case chain? Not sure its the shafts being out of balance either as they are new and came from a highly recommended company in AZ. I did run in HILOC with just the rear shaft for maybe 20 miles just to the line x shop and back and was really bad. Improved greatly once I got the front shaft on. I drive it just fine but it can't be doing something any good!

Is it me or is this normal? I would expect this if I had more lift.
Thanks for the help and advise in advance.
Dave

 

[owenst7]

So I have this vibration at 30 to 35 mph. Goes away on the hwy but is really bad on residential streets. I have search and most of what I have found is when you do not have a rear CV. I have a rear CV so I am at the glorious K5 brick wall.

Specs:
350 motor, 350 tranny, 203 full time (no PT kit) , 4" lift- springs in the front block and AAL in the back, 33x10.50 TSL radials. Its a mall crawler I know!

Whats New:

New front drive shaft with CV
New rear drive shaft with CV
New T case mounts (Energy Susp. Poly)
New motor mounts-Autozone nothing fancy.

Could it be the pinion angle?? I'm not sure it is, as the vibs seem to be at the front of t case? Could it be the t case chain? Not sure its the shafts being out of balance either as they are new and came from a highly recommended company in AZ. I did run in HILOC with just the rear shaft for maybe 20 miles just to the line x shop and back and was really bad. Improved greatly once I got the front shaft on. I drive it just fine but it can't be doing something any good!

Is it me or is this normal? I would expect this if I had more lift.
Thanks for the help and advise in advance.
Dave

What is your pinion angle? Pictures would help. With a CV rear, you ideally should have zero angle between the axle pinion and the driveshaft. If you installed a CV shaft in place of a non-CV shaft without changing the pinion angle...there's your problem. Get some shims or an angled block, or go back to a regular driveshaft.

T-case chains aren't going to cause a vibration like that. Keep the part-time kits out of that 203 and use non-detergent 30 weight in it, and it should keep you happy for a long time...wish my PO had the sense to do that...

 

[BIOHZDK5]

Oh one more thing I forgot, it is only when I have the accelerator push and constant torque on the motor. Going down a hill with no throttle, rides like a dream.

Well.......... like a lifted Chevy on swampers dream!

 

[BIOHZDK5]

Thanks Owen, that was my first guess but wanted to confirm it. I eventually want to flip the shackles and get new rear springs. Not real wild about the block AAL combo I got going on but when I restored her only had a limited budget.