Vibration concerns

[Ken Springhorn]

Is any one having any suddne vibration problems.  2010 express 4500(supposedly) just started bad vibration from what appears to be the rear.  Have switched, replaced tires(new) wheels until I can't lift any more.  drives OK til you hit about 70 and then speeds above  that feels like the rear of the rig is going to come off.  Drive shaft runs true, u-joints are good, trans mount is good.  Every once in awhile on take off I hear a moan coming from the rear.  Haven't figured that out yet.  there is a little over 50k on AEV built rig.  Any ideas would help.
 
thanks
 
Ken Springhorn
Jackson county Ambulance Service
Carbondale, Illinois 62901
 
 
 
side note--been having problems with 2009 A/C.  clutch locked up threw belt--new compressor, belt etc.  Compressor lasted about 3 weeks and clutch sheared it self---have new one on and now will not cool.  Been on about 3 weeks.  High side pressure in close to 100 and low side is 50 or below.  Freon charge is OK.  Thinking compressor is bad again--hard to believe. 
 
Ken

[Art Groux]

We are not having a vibration with an express van however we have a 2010 Tahoe that has a vibration at 1300-1700 rpm’s and the dealer tried changing the transmission program because they said that this had been a problem with the express van that has the same transmission and this reprogram fixes it.  They explained that it was the lockup point of the torque converter that was causing it.  Just so you know it didn’t fix our problem.  Not sure if this helps but figured I would pass it along.

 

Art Groux, Chief

Suffield EMS

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[Art Groux]

Our in house mechanic says the A/C system needs to be flushed and the expansion valve needs to be replaced (he believes it is partially or completely plugged).  We had a similar problem with one of our C4500’s.

Art Groux

 

From: nemsma-...@googlegroups.com [mailto:nemsma-...@googlegroups.com] On Behalf Of Ken Springhorn
Sent: Monday, June 18, 2012 3:54 PM
To: nemsma-...@googlegroups.com
Subject: Vibration concerns

 

Is any one having any suddne vibration problems.  2010 express 4500(supposedly) just started bad vibration from what appears to be the rear.  Have switched, replaced tires(new) wheels until I can't lift any more.  drives OK til you hit about 70 and then speeds above  that feels like the rear of the rig is going to come off.  Drive shaft runs true, u-joints are good, trans mount is good.  Every once in awhile on take off I hear a moan coming from the rear.  Haven't figured that out yet.  there is a little over 50k on AEV built rig.  Any ideas would help.

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[Ken Springhorn]

Flushed the system the first time---ran it for 15 minutes on hight idel this afternoon and pressures read 105 low side and 100 high side.  Was leaning toward a partially blocked orifice tube.

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From: agr...@comcast.net
To: nemsma-...@googlegroups.com
Subject: RE: Vibration concerns
Date: Mon, 18 Jun 2012 17:49:56 -0400

[Michael Bellinger]

We have 2 Chevys replace the rear bearing in one already just replace the shorted fuse blocks, I hope not to see another Chevy unless we go type one. AC fluch acumulator filter and condensor is always replaced or serviced or the compressor will fail. Air gap on the AC clutch has to be double checked not always shimmed rite. Good Luck Michael Guilfoyle Ambulance up state NY

[Ken Springhorn]

Thanks--any difinitive place as to where the filter is in line with the Duramax---shop manual is not to clear
 
Ken
 

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Date: Tue, 19 Jun 2012 07:16:51 -0700
From: mgb...@yahoo.com
Subject: Re: Vibration concerns
To: nemsma-...@googlegroups.com