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Author Topic: V730 shimmy/shake  (Read 3001 times)
brando4905
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« on: March 09, 2011, 05:43:52 AM »

Hey Folks,

When I take off from a stop I get a shimmy or shake for a hundred feet of so, then all is well and no slipping or shimmy in any other gear. Taking off real slow helps, but still feel a shimmy. Could this be bad motor mounts or something other than the trans.? Fluid is at correct level and has new filter.

Thanks,
Brandon
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1980 GMC H8H-649  8V71/V730 Marion,NC

"The highway is for gamblers, better use your sense" -Dylan
mcidave
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« Reply #1 on: March 09, 2011, 06:19:40 AM »

I do not get the shimmy/shake with my trans...But I do get a real hard buck right at the end of the granny gear going into the second gear and after that all is smooth!
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luvrbus
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« Reply #2 on: March 09, 2011, 06:22:04 AM »

If a GM has a drive shaft out of time U joints will cause that
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mcidave
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« Reply #3 on: March 09, 2011, 06:24:57 AM »

It a MCI9 1982 model but will keep that in mind when I get the tranny services comming up.
Thanks
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brando4905
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« Reply #4 on: March 09, 2011, 06:29:01 AM »

Clifford,

Thanks for the reply, how do I tell if they are out of time? Bad motor mounts not an issue in this situation?
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1980 GMC H8H-649  8V71/V730 Marion,NC

"The highway is for gamblers, better use your sense" -Dylan
bevans6
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« Reply #5 on: March 09, 2011, 07:07:43 AM »

very easy visual inspection, normally the U=joint caps are in line with each other.  the  driveshaft can vibrate a bit or cause a bit of a surge if the caps are out of line, more so the greater the angle the joints are at.

Brian
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1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
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luvrbus
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« Reply #6 on: March 09, 2011, 07:24:06 AM »

Brandon, the drive line should have arrows to time the shaft align the arrows all there is to it


good luck
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brando4905
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« Reply #7 on: March 09, 2011, 07:25:55 AM »

Thanks guys, I'll let you know what I find out.
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1980 GMC H8H-649  8V71/V730 Marion,NC

"The highway is for gamblers, better use your sense" -Dylan
gus
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« Reply #8 on: March 09, 2011, 03:04:22 PM »

Your slip joint grooves may be worn out, happened to me with the same symptoms and also a clicking at very slow speed.
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Charley Davidson
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« Reply #9 on: March 09, 2011, 03:41:05 PM »

I would make sure your U joints are good, I broke a tranny in half on my 4905 cause the front U joint gave out & the drive shaft came loose at the differential and bound up in the bulkhead at 70 mph.
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brando4905
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« Reply #10 on: March 10, 2011, 04:00:09 AM »

Gus,

Gonna check all of this out today hopefully, really hoping it's something in the drive shaft.

Charley,

That does not sound good, I've heard similar horror stories about buffalo drive shafts doing serious damage.
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1980 GMC H8H-649  8V71/V730 Marion,NC

"The highway is for gamblers, better use your sense" -Dylan
robertglines1
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« Reply #11 on: March 10, 2011, 11:38:05 AM »

If it is not drive line connected--check pulley for looseness on engine as they will sometimes correct with rpm building. or the smart mouth part of me says   Don't start off on rumble strips!  wishing it is a simple fix. Happy bussing  Bob   please post findings
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Bob@Judy  98 XLE prevost with 3 slides --Home done---last one! SW INdiana
robertglines1
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« Reply #12 on: March 10, 2011, 11:39:52 AM »

Does it do it when trans warmed up?
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Bob@Judy  98 XLE prevost with 3 slides --Home done---last one! SW INdiana
buswarrior
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« Reply #13 on: March 11, 2011, 06:22:51 AM »

Brandon, go find Bill Gerrie over at BNO, he's pretty good with the V trannies.

happy coaching!
buswarrior
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brando4905
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« Reply #14 on: March 11, 2011, 08:39:09 AM »

Thanks guys for all the suggestions. Drive shaft and u-joints seem OK, but have found a pretty good size crack in the rear bulkhead. Angry Angry

My mechanic is going to plate the damaged area with 1/4" steel on both sides. Got a feeling this is where the shimmy is coming from.

I'll give an update when we figure it out.

Thanks,
Brandon
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1980 GMC H8H-649  8V71/V730 Marion,NC

"The highway is for gamblers, better use your sense" -Dylan
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