So my family and i were about to take a vacation to florida in my dad's 96 Ram and about a week or two before the vacation started having a really bad shimmy comming from the rear of my dads truck. The night before we left i jacked up the rear of my dad's truck and did not find any play when i tried moving the rear tire up and down and side to side. But when i moved the rear well in and out, i noticed some play. I don't know what is acceptable for this movement? My first thoughts after seeing this movement i was thinking that the bearings on the outer sides of the rear axle are wore....after that i was wondering if the rear diff it's self is going? The shimmy happens roughly at various speeds then goes away and comes back randomly. Often the shimmy comes after hitting bumps. Any body have any idea on what could be causing this problem please let me know!! Thanks for any help.

 

Also I thought I should mention that the rims were checked to be true and not bent. The tires were also balanced and an alignment was done on the truck.

 

hmmm...thats a new one..... how old r your u joints?

 

its normal for the rear axles to slide in/out about 1/8-3/16 inch. its the play in the c-clip slot where the axles are held in place.

check the tires for knots or bumps.
have rear tires rebalanced.
check u-joints. trans in neutral, brake off, tension off driveline, try to wiggle the u-joints at front and rear of drive shaft. should be no play. push up/down on pinion yoke. should be no play.
check leaf springs, shackles, hangers for no breaks, cracks, play.

 

When I get home I will definently be checking those things out. Also can anyone tell me what is a good replacement differential for this trucks? Is the factory trac lock limited slip a strong enough differential or would a Dana true trac be better. I guess if I end up having to replace the difeential I want to know what the best option is for replacement with limited slip?

 

I had the same problem, more noticeable at lower speeds. It ended up that my tires were shot(multiple bands broken). After i got new tires put on I have never had a problem. I am not saying this is your problem, but it is something to think about.

 

98 blue ram thats very interesting that you had that problem with the bad tires. My father and i about a week before we left had thought this was our problem too. In fact we went as far as to jack the truck up in the rear and found that the left rear tire had a horrible wobble in as if a band was broke. We got this tire replaced with a brand new tire and still found the truck to have this odd shimmy. I think the tire shop is getting fed up with my father and i since i believe the truck has been in 4 times now trying to address this problem along with an initiall alignment.

My question is now that if the bad tire (or what we thought was a bad tire) could cause damage to some rear end component, whether it be bearings or what. i guess when i get home i really just have to get the cover off the differential and maybe pull out the axle tubes. But before i left for this trip the problem was really confusing the crap out of me.

 

Usually, its just a problem with an old set of tires. I had a slight shimmy from the back of my truck. Got new tires today and it was gone.

 

tires are only about 18 months old or so. And we just had the one replaced last week that we suspected had a bad belt in it. The tires probably only have about 10,000 -12,000 miles on them at best too.