Re: [Diesel-RVs] Re: Vibration when coasting.

Ken is correct. There should be no end play in either the pinion or the
carrier brgs. Actually they both should be pre-loaded to a certain torque
spec. The only place there is clearance is between the ring gear and pinion.

Darrel Goheen
PressurePro@tvnav.com

http://www.tvnav.com/pressurepro.html

Voice 785-625-3546/FAX 413-383-8800

----- Original Message -----
From: "Russ Waterhouse" <mredsel890@earthlink.net>
To: <Diesel-RVs@yahoogroups.com>
Sent: Friday, February 08, 2008 2:45 AM
Subject: Re: [Diesel-RVs] Re: Vibration when coasting.


> Ken,
> When you say there should be no play in the pinion shaft. You should
> explain in a
> forward and reverse manner. There is some "twist" play, but none in up and
> down, or
> forward and back.
> Russ
> ----- Original Message -----
> From: "Kenneth Molloy" <ken@molloys.org>
> To: <Diesel-RVs@yahoogroups.com>
> Sent: Friday, February 08, 2008 12:26 AM
> Subject: [Diesel-RVs] Re: Vibration when coasting.
>
>
> : --- In Diesel-RVs@yahoogroups.com, fred hengel <fjh1@...> wrote:
> : >
> : > Hi Phil and Mike,
> : >
> : > I really hate to be negative on mechanical issues as they can really
> : > surprise you sometimes. It seems to me any competent shop would
> : have already suggested replacing the U-joints when they saw zerks
> : missing and a dry condition. Especially when they diagnosed bad
> : pinion bearings. I too would change the u-joints and test before
> : pulling the rear apart. You are talking lots of labor $ verses
> : minimal labor $ to be sure.
> : >
> :
> : This whole scenario reminds me of an incident which made it on one of
> : the television programs a few years ago. A couple in a motorhome
> : would be cruising down the freeway in Arizona when a pickup would
> : pull up alongside and wave them down, telling them there was smoke
> : coming from the rear end. The MH was then advised to take a nearby
> : exit and take it to a shop where the mechanic rolled under the rear
> : end and removed the differential cover, then came out with a greasy
> : rag full of metal shavings he said came out of the rear end.
> :
> : The shop was able to locate a good used differential assembly for
> : about $500, and when it came, they would install it. Several RVers
> : had fallen into this same trap, and the television shop finally set
> : up a motorhome with a TV camera directly above the rear axle, and
> : then drove down that same stretch of the freeway. They caught
> : the "mechanic" taking a greasy rag full of shavings under the MH and
> : then opening it up and showing it to the RVer. Then the "used
> : differential" turned out to be the original one after it was all
> : cleaned up.
> :
> : The Arizona state police arrested everybody who was involved and when
> : the differential was properly reinstalled, there were no problems.
> : They had been victims of a scam.
> :
> : When I was a mechanic, I did a lot of rear axle work -- possibly
> : because I was the only mechanic in the shop who owned a dial
> : indicator. There should be NO END PLAY in the tail pinion! NONE!
> : Depending on the rear axle manufacturer and model, the preload on the
> : pinion bearings is usually set by torqueing the nut on the yoke to a
> : certain value, which crushes a bushing on the shaft. That "crush
> : bushing" has to be replaced every time the yoke nut is removed.
> :
> : If there were zerk fitting missing from the U-joints, that alone is
> : good reason for replacing the U-joint. If you just screw in a new
> : zerk fitting and grease the U-joint, you would be forcing every grain
> : of sand right into the needle bearings!
> :
> : U-joint kits aren't very expensive, and the labor to remove the drive
> : shaft, replace the U-joints, and reinstall the drive shaft shouldn't
> : exceed 3 to 3-1/2 hours.
> :
> : More than 50 years experience as an automobile, airplane and RV
> : mechanic have taught me that when you have a problem like this, look
> : at the last thing which was done before the problem started. In this
> : case, the driveline was removed for towing. Apparently there was no
> : vibration before the driveline was removed, but now there is
> : vibration! Bingo! Eureka! Problem solved!
> :
> : I still believe the problem will end up being that the two yokes on
> : the ends of the driveshaft are not aligned in the same plane. That
> : will very definitely cause a vibration.
> :
> : Ken Molloy
> : '94 Allegro Bay 37' MH
> :
> :
> :
> : --------------------------------------------
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> :
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> :
> :
> :
> :
>
>
>
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> Off-topic posts will be removed.
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>
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>

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