98 GMC 2500 Slight shutter on take off

I have had a slight shutter in the drive train, in 2 wheel drive, at standing starts or low speed (first gear) accelerations. It is only noticable once in a while and always disapears when I level off or get into second gear. It is a 98 2500 ext cab 4x4 auto 8' box with 46,000 miles and 285 x 16's. My warranty is up at 60,000 and I have put on about 20,000 trying to get it fixed.

Dealer can't find anything, but did replace all the u-joints and said that could have been it. Still does it. I think it could be a trany mount or carrier bushing, they say no. A buddy told me the limited slip does this and don't worry about it. I could see that maybe, if I was in stone or turning from a stop, but not on dry pavement going straight.

Went and had tires rebalanced, what for? I wanted to check for lug nut tightness and was curious.

Anyone else have this slight shutter like feeling?

Thanks, Bob V
 

John DiMartino

PlowSite.com Veteran
Location
Walden,NY
Has your dealer checked the pinion angle,if the truck is lifted or the axle wasnt flanged correctly/or the truck has hit somthing pretty hard in the back,it may have changed,this is usually a problem on lifted trucks only,but at t his point they have checked almost everything else.Unlikely but also possible is the ring and pinion are worn out or a tooth is 1/2 chipped off the ring gear,not likely but when all else fails....The torque side(drivers) side motor mount should be looked at also,as should the exhaust system,to see if its hitting somewhere,when the engine torques,make sure they check by the spare tire.Good luck
 
John ,

Nope, truck has not been lifted, except to turn up the front when I bought the plow 3 years ago. Never hit anything hard that I know of.

This shutter makes no noise or growl, only can feel it, like tires slipping slightly, but I'm not hard on the pedal. Normal acceleration.

They will have the truck on Monday the 23rd to have the drive shaft balanced and I'll have them check the motor mounts and ask about the ring and pinion wear. But I would think if that was it then I would feel it all the time, don't you? Maybe.

Thanks, Bob V.
 

dozer

Junior Member
If I read it right you have a manual tranny, had a old beater in high school, did same till I replaced throw out bearing and a heavier clutch assembly. Just another "what about....". Good Luck.
 

John DiMartino

PlowSite.com Veteran
Location
Walden,NY
Bob, the limited slip rear is not used by GM, I have both Dodge and Gm trucks,the Dodges use them,Gm uses the Locker style.The locker should not shudder when in free wheel mode,it takes a certain RPM difference between the 2 axles,AND the speed must be below about 10 mph or the locker will not kick in at all,You shouldnt need an additive for the gm locker either.Even when i dont add an additive to my Dodge,it will not shudder in a straight line,only when making turns,sharp turns.
 
Thanks John,

It was just a suggestion from a friend and I thought I would include it in my thoughts as to what might be the problem.:confused:

I still believe it is in the mounts or carrier bearing. I have had several Dodge (72 & 76) Power Wagon and Sno Fighter that had carrier bearings go, but that was a few years back, and they seemed to have the same type of shutter. Also had tranny mount go on 1980 F250 and motor mount go on 1978 F250. The F250 motor mount you knew pretty much what was going on.

Probably have to trade up to get this problem out of my hair.
 

John DiMartino

PlowSite.com Veteran
Location
Walden,NY
Bob,I'd replace the carrier bearing anyway,its cheap,and to to hard to do.Dodges that tow heavy eat them and they shudder the same.Some of the 2001 GM HD's shuddered so bad that GM made a 1 piece shaft made to repalce the 2 piece.
 
John DiMartino,

I pull quite a few hay wagons home durring summer months and usually 2 at a time with 7000lbs on each and each wagon wieghing in at 2000lbs for a total of 18,000lbs, that I'm pulling through rough fields and down the shoulder of the back roads. So what you say about "Dodges that tow heavy eat them" sounds like I'm back to what I origanally told the dealer it could be.

Even though they can't see anything wrong with the carrier bearing, I will insist that they replace it Monday when they take the shaft off to balance it.

Thanks, I'll let you know how I make out.
 
Got the shaft balanced and again they say the carrier is in good shape. Noticed on the way home the shaft is vibrating worse than ever. Now I wish I would have never tried to get the slight vibration fixed. Big mistake. I will have to take it back in, Again.

Maybe they installed the caps not fully seated. I will look when the sun comes up.
 
Update:

Went back to Dealer this AM and mechanic found slight play in splined shaft and also found the 2 shafts were not lined up to each other. He slid them apart and tried to line up the 2 shafts and couldn't seem to get the caps from front shaft and rear shaft to line up.

Says it must have been this way from factory. They ordered a new shaft assembly and will get it in next week.

Bob V
 

Joey D

Senior Member
Location
Arlington,MA
The locking rear could be what your feeling. It will chatter from time to time. Not to say it's not the driveshaft. Have you changed the rear fluid yet?
 
Havn't got to the rear-end yet. I'll wait till they get it up on the lift and put the new shaft on and then I'll make the comment about changing the fluid. I'll let them put all the new parts on that they want as long as it is covered under the warrenty.

Thanks for the suggestion.

Bob V
 

Joey D

Senior Member
Location
Arlington,MA
Bob, I would also let them replace all the parts they want to. Has the rear fluid be changed at all? At 46,000 it should have been changed at least twice. The most noticable time my truck will do this is when coming off the freeway where there is a light to stop at then making a turn it will chatter.
 
Joey D,

I have had the truck since 22,000 miles and I put the first plow on it. No I have never changed the rear-end fluid.....Yet! Will ask them do it when they are tightening the the shaft u-bolt nuts.

What are your thoughts about the trany fluid and filter? Might as well work our way up to the front-end and see how much more I can get replaced before the warrenty runs out.

Just kidding....I really want the shutter/vibration to be taken care of. That would make me feel better.

Bob V
 

plowking35

2000 Club Member
Location
SE CT
Bob, I change my fluid and filter everey fall. If it hasnt been done, do it. I also have changed the rear diff fluid at 7500 miles and again at 50K, with the additive. My locker works with no sound at all.
Dino
 

paul soccodato

Senior Member
Location
westchester ny
if the rear has a locker in it, you shouldnt have to put an additive in it, if it has a limited slip, with friction plates in it, then put the additive. it prevents the plates from chattering while turning.
 

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