I just replaced my front driveshaft, and now the truck vibrates quite a bit at 63-64 MPH. Actually, it vibrates above 50, but 63-64 is when it's at it's worst. I got it up to 80 for a second, and the vibrations seem to get less the farther I get from 63-64. Is this just an out of balance driveshaft? It wasn't vibrating nearly this bad before the swap. Thanks.
You didn't say what you swapped really and why? What was wrong with your old drive shaft? The new one might be out of balance...where did you get the new one? Tried taking out the drive shaft?
It now has a rebuilt stock driveshaft. The problem I was having (I posted about it a while ago thinking it may be the VC) was that when the wheels were at full lock either direction, there was a nasty clicking noise which sounded like gears not meshing. It would continue once the wheels were straightened out for a few seconds and then go away. I honestly thought it was the CV joints after some input from the board here. Last week the problem persisted even after straightening the wheels out. I took it to a parking lot, did some figure 8's at low speed, and the entire truck was bucking badly, such that I felt it in the rear wheels. I took it to a mechanic a few doors down from where I work, and he told me the driveshaft was coming apart, that it wasn't the VC (knew that) or the CV joints, and, LONG story short, he replaced the driveshaft. No more clicking at full lock, but the vibration is pretty bad, as stated in my first post.
I know the tires have low tread, and need to be replaced, so I would agree that they're also probably out of balance. The only variable here is the new driveshaft, as it didn't vibrate nearly this bad with the old one in, so while I don't doubt that out of balance tires are part of it, I'm just wondering if it's the driveshaft. I'll probably take it back and have the shop look at it since it has a warranty, but I'd rather not go back there again if I can help it. I'm hoping if it's the driveshaft I can somehow diagnose that myself before I go and deal with the shop again.
As for removing the driveshaft, I'm afraid to do so and drive it because for every person that swears it's okay to do so, there's someone who swears it will fry my VC, and I'm not willing to take the risk. The mechanic who did the work told me that taking it out and driving would be a bad thing as well, so I'd rather err on the side of caution and not try it.
Well 96+ ZJ's with the 249 are ok to remove the front DS...Pre 96 it is not ok. Plus removing it for a short trip up to 65 and back wouldn't hurt the VC anyways and is probably the only sure fire way to figure if it is the DS or not. What did the shop do to the DS? It probably just needs to be balanced...
I was told it is a rebuilt shaft, not the original. The old shaft was supposedly deteriorating due to rust and age. The spot where the two shafts join was deteriorating or something.
In short, I know I got screwed by this shop, but given it was literally next door to my work, and I wasn't going to drive the six miles home with that problem, I consider it a convienence tax to get the problem taken care of. I dropped it off last Tuesday afternoon, and it took them until Friday morning to find a place which had a rebuilt driveshaft in stock which fit my truck.
The grand total for the repair was $706, which included replacing the pinion seal. Yes, I know I got ripped off, but in a million years I would have never diagnosed the driveshaft as the problem. I know not to go back to them (hell, I knew not to go to them in the first place, but I was kind of stuck), as they never really stuck me as being too honest. Plus, at $100/hour their labor rates are obscene. AND they charged me a $50 diagnostic fee on top of the work they did, which I've never had happen.
My Grand Cherokee came new with the kind of vibration you mentioned. I had the front driveshaft replaced several times under warrantee, one swap made it a little better; one a bit worse. I ended up trying to return the car under the NJ lemon law. I lost my case as Chrysler successfully made the case that ALL Grand Cherokees shake like mine and yours on the highway! What a crock of s**t!
Anyway, after I lost the suit against Chrysler, I decided to take matters into my own hands. I took the driveshaft out (very easy), and brought it to a local driveshaft shop. I had them balance the shaft. They told me that the factory balance was off by a huge amount. Needless to say, this solved the highway vibration, (or at the very least, got me to what Chrysler was talking about in terms of normal levels of vibration!) This cost $75. I can't believe that even with the huge stink I made, and the fact that three different service managers agreed that I had a problem; no one could or would fix it! Even though I still have this Jeep, this is also why my new SUV is a 4Runner.
I may end up doing this. It's almost worth the $75 to do it myself and not deal with that shop again.
This front drive shaft is definately a design flaw of these Jeeps. I think the fact that they put a CV joint in the shaft instead of a regualr driveshaft slip joint is an indication that they were trying to put a band aid on the problem. It probably became a real issue when they came out with the full time 4WD vehicles like mine, and from the results I had, clearly Chrysler played Ostrich on this one.