johnathan
1/2 ton status
I'm getting a grinding vibration 50mph & up .I've had this vib. for a while I've changed the driveshaft,swapped rearend so I'm guessing it would be transfer case maybe,np208.Has anyone ever had this problem?
CK5
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the vibration hunt
- Thread starter johnathan
- Start date
johnathan
1/2 ton status
yeah 208 is slip yoke ,1310 in front of shaft 1350 in rear, no lift, don't know the angle of shaft ,I did'nt suspect that since it should still be stock
johnathan
1/2 ton status
one piece shaft
johnathan
1/2 ton status
i swaped in a new shaft because the old one was just worn out. joints are new.I had the same exact vibe same speed with the old shaft.i never had the new one balanced ,it is used ,from newer blazer.there is a little play at the slip yoke.
K5Steve
1/2 ton status
How long is the d shaft?My slip yoke was sticking out of the t case about 2 inches more than it should've been.It is being lengthened from 29 1/2"
to 31 1/4".My pinion yoke was shot,bought a new one,my slip yoke was worn,bought a new one,and had my d shaft balanced with new spicer joints.It was still vibing,just not as bad.I'm hoping the lengthening works,I also had play in the slip yoke.
to 31 1/4".My pinion yoke was shot,bought a new one,my slip yoke was worn,bought a new one,and had my d shaft balanced with new spicer joints.It was still vibing,just not as bad.I'm hoping the lengthening works,I also had play in the slip yoke.
K5Steve
1/2 ton status
It worked for me a little,most of my vibes were coming from the exploded gov lok in the rear end.Doesn't vibe now.
johnathan
1/2 ton status
after the shackle flip lift with new cv shaft no more vibes 
had to shim 4degrees
had to shim 4degrees
K5Steve
1/2 ton status
Sweet,I need to redo the lift on my truck,blocks.I hope to get rid of the axle wrap afterwards.
I'm on the vibration hunt too. But it's a strange one, more RPM related than speed related. Old school small block with 700r4, no lift kit. Vibrates in all gears above abut 3,000 RPM. Upshift or lock the converter, vibration goes away. So it's the engine you say? That's what I thought but I can rev it to the moon in neutral, even while coasting, no vibes. Like I said, strange.
Have a clutch fan on it ?...
Might be a bent blade,and when you rev it in neutral the clutch lets the blade "slip" and temporarily stops the vibration..
I've had a fan clutch loosen up (play in the bearings) and make a vibration before...I could wiggle the blade back and forth a 1/4" !.
Might be a bent blade,and when you rev it in neutral the clutch lets the blade "slip" and temporarily stops the vibration..
I've had a fan clutch loosen up (play in the bearings) and make a vibration before...I could wiggle the blade back and forth a 1/4" !.
Wow, great thought, I have a flex fan however. It feels just like a driveshaft/U-joint thing except it varies by rpm not speed. Your diesel handle though reminds me, my K5 was originally a diesel and I'm pretty sure it has the diesel 700r4 and converter (6 bolt lugs). I didn't do the SBC swap, got it this way. Maybe it has a diesel externally balanced flex plate? Would that fit an old SBC?
Thanks for the reply.
Thanks for the reply.
I am pretty sure the 6.2 crank has the same bolt pattern as a gas V8,but the diesel's flywheel has an external balance weight on it--so if it was used on a gas engine it'll vibrate ,probably pretty badly..
I'm not sure if you could just remove the balance weight if in fact they did use the diesel flex plate--but now that I think about it--the diesel also has a different tooth count and starter drive gear tooth count,so it probably wouldn't mesh well enough with a gas starter to even crank it over...(if its even the same diameter,I dont know if the diesel vs gas are the same diameter)..
They may have just drilled the other 3 holes in the gas engine's flex plate,or just used the 3 out of 6 bolts that lined up and left the other three bolts off ?..I know a few guys who put gas engines to a TH400 with the 6 bolt converter and just used 3 bolts with no issues..
I'm not sure if you could just remove the balance weight if in fact they did use the diesel flex plate--but now that I think about it--the diesel also has a different tooth count and starter drive gear tooth count,so it probably wouldn't mesh well enough with a gas starter to even crank it over...(if its even the same diameter,I dont know if the diesel vs gas are the same diameter)..
They may have just drilled the other 3 holes in the gas engine's flex plate,or just used the 3 out of 6 bolts that lined up and left the other three bolts off ?..I know a few guys who put gas engines to a TH400 with the 6 bolt converter and just used 3 bolts with no issues..
I forgot to update this thread. I finally noticed my engine to trans bolts were loose, with an air gap on one side! (I didn't put it together). Fixed that, much better.
On another note, it is true about backing up to unlock the front axle on a stock '83 K5 with auto hubs and 10 bolt? I use 4WD frequently, marked the front shaft once and it was in the same spot without backing up first but it does seem smoother sometimes rather than others. Lastly, are there bearings in the transfer case that might cause vibration?
On another note, it is true about backing up to unlock the front axle on a stock '83 K5 with auto hubs and 10 bolt? I use 4WD frequently, marked the front shaft once and it was in the same spot without backing up first but it does seem smoother sometimes rather than others. Lastly, are there bearings in the transfer case that might cause vibration?
