Vibration while accelerating

[WaltZ]

Current miles: 170,000

When the speedo hits 55mph, there is a very noticeable vibration and noise throughout the vehicle. This only happens when I press the gas pedal. If I take my foot off, the vibration goes away, no matter what speed I’m at. Once I get past 75mph, the vibration is very subtle, but still present.

I had the local former Mercury dealer replace the front wheel bearing (it needed to be replaced anyway) and I had them change the tranny fluid (it’s never been done). They lifted the vehicle and ran up past 55mph. The tech ran a stethoscope and thinks the bearing in the transfer case is bad. The fluid was burnt. They replaced the fluid and nothing has changed. They also recommended a new front axle. They said I can go out and get used parts (eBay) and they will install.

I’ve seen similar issues with Explorers, but their T-cases are different than the Mounty.

Anyone else here with a Mounty had a similar issue? From what I’ve been reading with the Explorer, it could possibly be just a bad u-joint. I hate to start spit-balling parts at it.

 

[Explorer_PL]

Are all wheels balanced ?
Check your engine mounts.
The transfer cases are not that much different - it's more that they engaged differently I believe.
On my Explorer, when the rear bearing went bad on the transfer case, I had a whining noise similar to the wheel bearing but I had no vibrations.
Did he say which bearing ? There are 4 main bearing on TC, the cost to rebuild the transfer case is close to getting a reman one on line.
When they say axle, do they mean one of the CV shafts ? They are inexpensive, even a reman ones go for about $ 60.
Can you do any work yourself ?

 

[WaltZ]

All the wheels are balanced. In fact, I just put on new Firestone's a month ago

I stopped by the dealership yesterday to get more details. The fluid in the t-case was in really bad shape, and along with the bearing noise, it didn't have too much life left. I pulled the trigger and found one on eBay for $450. There was only 1 used one listed that was a direct replacement.

I did clarify with them that it was not an axle issue, but the front drive shaft that needs to be replaced. I can get a used one on eBay for $75+ (and cross my fingers it will last) or buy a new Dorman for $209. I will buy the new one.

I looked at some video's of changing the T-case and it's well above my skill, tool and comfort level.

Thanks

 

[Explorer_PL]

I got one of these and so far so good.

You searched for Part Finder - Detroit Axle

 

[WaltZ]

Just a followup to my original post:

I got the tranny fluid/filter changed on visit #1. The next morning when backing out of the garage, I noticed a "clunk" when shifting from P to R. No noise from R to D. I just attributed it to it needing a new T-case and front driveline.

I got the new T-case and driveline installed on visit #2. Next morning, same clunk and all day when going from P to R, hot or cold. I recently heard, but not as loud, a clunk when slowing down (10mph or so) when vehicle down-shifts. The "tech" made a comment to the supervisor that the rear differential has a small noise and may need to be replaced (this would be the 2nd BTW). The vibration I had is gone, BUT, the noticeable noise when accelerating after 40mph, is still there. No noise when I let up on the gas and coast. **EDIT**. now its a thumping sound over 30mph. Sound like a flat tire. The sound gets faster as the vehicle gets faster. Volume goes down over 55mph.

I called the dealer yesterday to ask them if there was a possibility they didn't fill the tranny completely and if they checked the rear u-joints. She said the tech checked and they were fine. He now says it could be the tranny. I can't afford to throw trannys and rear axles at this truck and hope it fixes the problem.

I have appointment Saturday at Firestone to replace an upper control arm under warranty. I'm going to get their opinion on this.

 

[gdgiordano]

Just a followup to my original post:

I got the tranny fluid/filter changed on visit #1. The next morning when backing out of the garage, I noticed a "clunk" when shifting from P to R. No noise from R to D. I just attributed it to it needing a new T-case and front driveline.

I got the new T-case and driveline installed on visit #2. Next morning, same clunk and all day when going from P to R, hot or cold. I recently heard, but not as loud, a clunk when slowing down (10mph or so) when vehicle down-shifts. The "tech" made a comment to the supervisor that the rear differential has a small noise and may need to be replaced (this would be the 2nd BTW). The vibration I had is gone, BUT, the noticeable noise when accelerating after 40mph, is still there. No noise when I let up on the gas and coast.

I called the dealer yesterday to ask them if there was a possibility they didn't fill the tranny completely and if they checked the rear u-joints. She said the tech checked and they were fine. He now says it could be the tranny. I can't afford to throw trannys and rear axles at this truck and hope it fixes the problem.

I have appointment Saturday at Firestone to replace an upper control arm under warranty. I'm going to get their opinion on this.

A lot of people report a vibration under acceleration in these past 40 mine does it too, but it goes away after 45 or 50. I also get a small clunk when shifting from p to r and r to p. Nothing odd on decel though.

In all honesty I think two of those things are just features of the vehicle past a certain age. My tranny fluid was dark when I changed it but had no metal or anything in it and my tcase looked good. My rear diff is pristine as well and I have a couple of the features you do. I’m knocking on every piece of wood I can find as I write this but I think it’s normal or at least no cause for panic.

 

[07EddyB]

In all honesty I think two of those things are just features of the vehicle past a certain age.

Agreed. I don't have the noises on my Ex yet but it's only at 105k. Things make more noise as they age - hopefully that doesn't mean that they are about to die. If so then I'm in trouble as my body has been complaining a lot in the past few years

 

[Gorb]

I had a very similar problem and it turned out that one of the rear cv shafts had a crack in the counterweight and all the weight material fell out. Mechanics started doing exactly what they're doing to you and nothing worked until I took it to another shop and they found it right away..., new front diff, 2 front cv shafts, tranny flush, 3 different transfer cases, 2 lower front control arms, both driveshafts rebuilt and the brake job and wheel bearing it originally went in for. Cost me 5 ****ing grand. Probably should have sued them I guess.

So check your cv shafts, the weights are right up against the differential

 

[WaltZ]

I just got a diff on eBay and should be here Thursday for a Friday install. I'll have them check the CV. I'm not sure if this will explain the clunk from P to R and 2 to 1 downshift. Now I'm hearing a P to D clunk. Seems to be getting worse.

Thanks for the heads up

 

[WaltZ]

SOLVED- It was the rear differential and axle. The rear diff was toast and one axle was just wobbling around. I got a new diff on eBay for $250 delivered and 2 new axles (the other was on its way out) and all is better in the world once again