Vibration from somewhere above 60 and below 75

[konstan]

engine mounts

Well, if it *were* the engine mounts, then you would be able to reproduce the vibration by sitting still and just revving the motor in park... You do not even have to rev it up that high.

At 65 mph, my RPM is below 2,000 which is really not that much, so I would not think you would notice any motor vibration due to engine mounts when going at 65 mph.

 

[d.bright]

I understand what your saying konstan, but if you read the TSB, here is what makes me think otherwise:

"This condition may improve with tire balancing or tire exchange, but may not be completely eliminated. This may be the result of the movement frequency of the engine aligning with the tire rotation frequency, causing the vibration/shake."

I am now going to do two things, I know the owner of a PTO/Driveshaft shop who will balance my driveshaft for free, so I'm going to go there tomorrow and have them balance it for me. After installing the shaft, if the vibration is still there, I'm going to install the new motor mounts (got them both today from Autozone for $30.00 with LLT Warranty). And the new Trans mount, which seems to be pretty worn.

I'm planning on getting the alignment anyways, so I figure I'll do that last.

I was at the pull-a-part a few days ago, and I looked at the difference between 1st and 2nd gen rear axles, the major things that I saw were how the rear sway bar was mounted (foward facing mounts on frame), and the addition of the rear axle stabilizer shock, I didn't think about getting that and putting it on mine, but I may go back and get one, it just makes sense that it would help stabilize the rear-end.

Has anyone ever swapped one on from a newer model?

Thanks for the comments guys, I appreciate all the input!

 

[CBII]

I'm having the same problem as you d.bright. I've had it into the tire shop several times and still not much change. The driveshaft is going in on Friday so I'm hoping that helps.

I've also replaced the tranny mounts but never thought of the motor mounts. Also never thought about adding that rear axle shock. I'm going to read more about that and consider it if the driveshaft doesn't fix the problem.

 

[konstan]

drive shaft

Are you guys replacing the u-joints in your driveshafts before paying someone to balance them?

I had a driveshaft shake on my dodge pickup. When I took it apart and replaced the u-joints, the old ones seemed ok... but I guess they weren't, because after I replaced them the problem was completely fixed.

I am only saying this because I think it would take something really violent for the driveshaft to become out of balance... You know, like its bent or something... or the balancing whatchamacallits that were welded to it fell of...

 

[d.bright]

Yet Another Update

OK, I went to the balance shop in South Atlanta (Atlanta Powertrain, great guys, ask for Mike Romines if you go there, and tell him Daniel sent ya), he made sure that the u-joints that I installed were done properly, which they werent perfectly installed, so he re-did one of them, and made sure it was all good.

He then put the shaft on the balancer and spun it about 2,000RPM, he immediately noticed a visible inbalance, so he did this cool thing where the spun it up fast, barely touched a peice of chalk on either side of the shaft while it was spinning to mark the high-points, and then he took a torch to the chalk line and then immediately ran water over it, about 3-4 times each side, after he did this, he spun it again and it was perfect (this guy knows his stuff), he didn't even have to put weights on it.

SO I got home, installed the shaft, and took it for a quick spin. Unfortunately, it didn't solve the problem, however it did make my accelleration smoother and also seemed to lessen the vibration about 10% or so.

I then decided to move my tires around, because it is cheap (free) and a quick way to determine if my tires really might be the problem. And guess what? I've had my tires balanced 2 times, and each time nothing helped, BUT this time, when I rotated my tires, the vibration almost went away, it's still there, but now it's in the front of the truck, and it's much more subdued, so now I know that I need a new tire (I'll probably spring for a set later on) and I've almost totally rebuilt my suspension chasing this thing down. I think kontan said he thought it was a wheel/alignment issue, and he was right. I'm going to go back to the tire shop and see if they can road-force match the tire to the rim, that may eliminate it as well.

I'll let you all know what happens. Guess I can take back my mounts and get some money back to put towards tires!

To anyone going thru this issue, try rotating your tires one side at a time, or both at once and see if it makes a difference, then you will know it's something to do with the tires/wheels.

 

[Alan_V]

Okay, so if you're down to 2 tires, put the spare on and see what happens.

 

[BP_93explorer]

i had a vibration on my explorer from the day i bought it. i was told the tires were new and they actually had a lot of tread left. drove it for a few years with the vibration but i didn't have to go on the highway much so it didn't bother me. i had gotten the tires balanced/rotated a few times in those few years and they never told me they needing replacing until the last time. the tread was almost gone at that point. purchased some new tires and the vibration hasn't been back since.

 

[d.bright]

That's funny, it sounds almost exactly like what I'm going thru, both rear tires were "new" according to the seller, however I fealt a vibration riding home on the highway, but since I never drove on the highway (until now, commuting to and from Atlanta) I never really cared. Also, both tires were mis-matched, one is a Goodyear Wrangler RT/S and the other some noname brand, the no-name brand is the crap tire, so I think I'll get 3 new RT/S's if I can find a good price. In the meantime, i'm going to get a cheap used tire to remedy the situation for a few months while I save for new tires.

I'll keep you posted on how it makes the ride.

 

[d.bright]

Instead of purchasing a set of new tires, since I still have at least 50% on my front 2 tires, and 60% on the rears, I am going to try and get a couple of used tires for now with at least 45% tread, and keep it going thru the summer until I save up for some Goodyear's or Michelins, I'm going to get some used tires swapped on hopefully Monday, I'll keep you all updated as to what difference it does or doesn't make, I figure 20$ a pop isn't a bad deal to get rid of a violent vibration for now.

 

[Alan_V]

Find a shop that can RFV balance (Road Force Variation) them if that hasn't been done already. RFV blance puts a load on the tire as it spins, simulating the weight of the vehicle on the tire. It has the capability to balance out a vibration in a tire that most shops swear is perfectly balanced. I know Hunter makes a machine and if you go to their website http://www.hunter.com/), you can put in your zip and find the closest shop with a GSP9700.

 

[CBII]

Well like d.bright I replaced the u-joints and re-balanced the rear drive shaft and it didn't completely correct the problem. It is better but still noticable.

I to will be looking for a set of used tires to get me through the summer and get a new set in the fall.

 

[d.bright]

Problem Resolved

Well folks, the issue is finally resolved. A new set of Cooper Discoverer H/T's did the trick. I was originally going to put a new set of tires on later in summer, I was all set to go on vacation this week, but I had to postpone because someone got really sick, and he's my only backup, so I just swapped the money around Now I'll take a vacation around August, but until then I get to enjoy the new tires!

These tires are great, if your not using your Ex for off-road, I recommend these tires highly, I was able to get a set for $90 a peice (I'm sure they're cheaper somewhere else, but I really like this local tire shop). So with the tires and alignment it all came out to be about $450.00, the cool thing for me is that I get lifetime rotate and balance, AND if one can't be balanced properly, if a road-force-variation balance doesn't cure it, within 60K miles I get a new tire free, pretty sweet deal.

I'll get some pics up for you guys to see, I have about a 2" lift in the back with these tires (custom shackles) and it looks pretty good.

Thanks for all the advice guys, now with all my suspension pretty much brand new, and these tires, my truck drives pretty darn near perfect.