Diagnosing Vibration

[jdjohn84]

I have seen several other threads on this forum of those who have had vibration issues. Add me to the list. There is a vibration when starting from a dead stop, and also a low-frequency roar vibration when at low RPMs at speeds in the 50-70mph range.

In both cases, when coasting there is no vibration. It is only when power is applied that the vibration occurs. If you let-off on the gas when the vibration is occurring, it will stop. Also, there is a occasional squeaking when starting from a stop as well. It sounds like a belt squeaking/squealing, but I'm wondering if it might be the rubber from an engine mount rubbing against metal. It's very hard to tell for sure what is causing the squeaking noise.

I replaced the transmission mount myself, but the engine mounts up front (left and right) stopped me from DIY mode. I may take it to a shop for those since I have come close to rounding-off one of the bolt heads, and there are obstacles in the way for the top mounting nut on the left side. By the way, the manuals don't mention this top nut on the engine mounts, so be aware!

The vibration may just be rough running from a plug/wire issue based on what I have read, but with the squeaking and roar (at higher speeds), and also a hard shift between reverse and drive, I'm still thinking mounts are the problem. The plug wires look fairly new, so I'm assuming all is okay there...for now.

I have no CEL or stored codes indicating misfires, so that leads me to bad mounts as well. I did have a CEL light and the P0171 lean code, but after cleaning the MAF, that light/code has vanished. I was able to pass emissions, too.

I will update this thread once I get the front engine mounts changed. Wish me luck!

BTW, this is a 2000 T4R SR5 2WD with 206K miles on it. I recently bought it from the original, single owner. Timing belt was changed just a couple months ago in Sept 2011, so I'm hoping it's good for another 100K miles! The oil is very clean, but ATF is dark red, so I will be changing that soon.

 

[iowajosh]

It sounds like u have a bad u-joint. :hiding:

 

[allwheeldrive]

It sounds like u have a bad u-joint. :hiding:

This.

 

[Kurtis]

It sounds like u have a bad u-joint. :hiding:

Sounds about right.

 

[traffic61]

Yup, what they said. Just went through this about two months ago.

 

[jdjohn84]

Wow...pretty unanimous. I've been searching for a DIY on this, but no luck so far. Anyone have a link? thanks

 

[Kurtis]

Wow...pretty unanimous. I've been searching for a DIY on this, but no luck so far. Anyone have a link? thanks

how to replace a u joint - Google Search

There is a couple videos for it too. I didn't get a chance to look at them. I am at work and the connect speed is terrible.

 

[STRRAYNGE]

I have seen several other threads on this forum of those who have had vibration issues. Add me to the list. There is a vibration when starting from a dead stop, and also a low-frequency roar vibration when at low RPMs at speeds in the 50-70mph range.

In both cases, when coasting there is no vibration. It is only when power is applied that the vibration occurs. If you let-off on the gas when the vibration is occurring, it will stop. Also, there is a occasional squeaking when starting from a stop as well. It sounds like a belt squeaking/squealing, but I'm wondering if it might be the rubber from an engine mount rubbing against metal. It's very hard to tell for sure what is causing the squeaking noise.

I have this exact issue! When accelerating, I am getting a pretty noticeable vibration up to however fast. As soon as I let off, and I am at a cruising speed, the vibes are gone. Once back on the gas to accelerate, its there again.

 

[jdjohn84]

So I assume we are talking about the u-joint spider and bearings. Is it normally the front one (tranny), or the rear one (diff)? Or do you go ahead and replace both?

 

[iowajosh]

They are cheap. Fix both with nice ones and be done long time. Don't mess up how the shaft is indexed. Everything is rotated a certain way and must go back the same way or it will keep making vibration. I spray painted a line down the joints onto the pipe, etc. Learn greasegun if you get greaseable joints.

 

[jdjohn84]

Thanks for the tips. I think I'll give it a whirl. I've got a vise that should be big enough to hold the saddles for pressing the bearings. How much tranny oil spills after the spindle is pulled out?

 

[jdjohn84]

I think I found the problem. And yes, there are a gazillion YouTube videos of how to change a u-joint. Changing this will be easier than the engine mounts, and I get to use a BFH!

 

[iowajosh]

When you have a flange with bolt holes, I had good luck screwing it to a block of wood so there's something for the vise to hold onto. Oh, one of those is rusty inside and that is your squeak.

 

[jdjohn84]

Yeah, one of the bolt holes in the vise flange is broken, so only two left. Of course a real work bench would be nice!

Yep, I'm hoping you're right about the squeaking coming from here. I wish I had noticed this when I was down there looking at the tranny mount.:redbrick:

 

[jdjohn84]

Just a follow-up to say that replacing the u-joints fixed the problem. Thanks guys! I have seen other threads about engine vibration at low rpms, and highway speed noise at low rpms, where spark plugs and/or tune-ups were needed, but I think the key to this one was that the noise stopped when I took my foot off the gas in every case. I think that zeroed it down to u-joints.

Suggestions:
1. Unless you already own a very big vice or press, just drop the drive shaft on your own, and then take it part-in-hand (replacement u-joints) to a shop that owns an arbour press or something similar, and let them replace the joints for you. I had a 5" vice that was too small. Then I bought a 6" vice at Home Depot ($70) and bent the handle trying to press-out the u-joint bearings. I gave up and took the drive shaft (in another car of course) to a shop with my replacements bearing in-hand, and they did the r&r on front and back u-joints for $75. Now I have two vices that I will rarely use, and I wasted my money on a new vice. There are u-joint tools available for about that same price of $75, but unless you think you will use it multiple times, just spend the money to let a shop do it for you.

2. Jack your vehicle up in the back for this job. First, by tilting the vehicle forward, you will keep tranny fluid leakage to a minimum when you pull the spline out. Second, when removing/installing the bolts and nuts on the back u-joint saddle that connects to the differential, you can spin the back wheels to rotate the saddle for the top bolts. They are much easier to work with when you rotate them to the bottom. This would require chocks under the front tires, gear shift in neutral, and no emergency brake on.

Mine is 2WD, so only two joints. Obviously with a 4WD it would be different if you did them all.

Thanks again for all the help!