Front Drive Train Work, Vibration Remaining

[ab_slack]

I had a few issues accumulating but had been holding off till I had the funds to get everything done at once to economize on the labor as I was having a shop do this.

Due to collapsed brake line that caused caliper to stay engaged the driver front had gotten severely overheated and smoked the grease and actually melted the center plastic knob on the locking hub. Not related to that I also had vibration starting around 35mph when hubs were locked (4WD on or off) including metallic dings and other not good sounding things.

So got the differential checked out, it seemed okay, changed fluid, nothing metallic in the diff fluid so am assuming nothing major there.

The wheel bearings on both sides replaced, rotors replaced and U-joints replaced. One of the u-joints was really bad and the one bearing on the passenger side used for the 4WD drive was also bad. Also put on a new set of warn locking hubs.

After all the work things are much improved. Most of the nasty noises are gone but there is a vibration that can be heard and felt that gets quite noticeable up around 50 mph.

I looked at the right side shaft between differential and wheel cause I seen people saying that phasing needs to be correct. The phasing definitely is not correct. Now having discussed with the shop they said it shouldn't make a difference and pointed to the small amount of movement the front drive shaft has where it comes out of the transfer case. A concern I had expressed to them in the first place.

So my question, with the side shaft phasing wrong, just how severe does the vibration get? Is that probably all I am experiencing? My inclination is that it needs to be taken care of anyway. the vibration doesn't seem related to the right side per se if that is also an indicator.

Second question is how much movement is acceptable where the front drive shaft connects tot he transfer case. The kind of movement I mean is if you push or pull the shaft perpendicular to its axis. Concern is that transfer case output bearing may be bad or splines are too worn.

Last question, referring back to the right side shaft, is balance a potential issue?

 

[exbass94]

I looked at the right side shaft between differential and wheel cause I seen people saying that phasing needs to be correct. The phasing definitely is not correct. Now having discussed with the shop they said it shouldn't make a difference

He's wrong. Having the phasing wrong WILL cause a vibration. Not "might" cause a vibration, it WILL cause a vibration. Get the phasing correct and report back. The vibration will at the very least get much better or probably go away entirely.

 

[black_demon69]

out of phase would mean that the u joints are binding alittle.. i would insist that they correct it immediately also make sure hubs are not locked and check tire pressure and balance and play in the wheel bearings bj ect..

assuming a d28 axel did you have the spindle bearings replaced?

just rebuilt the front end on mine and the spindle bearings were totally gone on my d35 and had alot of play in the axel before i replaced them..

just a few random thoughts

 

[ab_slack]

assuming a d28 axel did you have the spindle bearings replaced?

No they weren't changed. And yes it is a dana28.

 

[ab_slack]

He's wrong. Having the phasing wrong WILL cause a vibration. Not "might" cause a vibration, it WILL cause a vibration. Get the phasing correct and report back. The vibration will at the very least get much better or probably go away entirely.

Thank you.

I am also curious how may splines (correct term?) are in the slip yoke? I am just wondering if it is fairly course so being off a tooth is obvious enough or if there are a whole bunch of little ones and one tooth may not be so obvious.

To me the side shaft looks like a drive shaft setup to allow for suspension travel and I would have expected phase to be important in the same way.

It isn't a bad shop, but they aren't immune to goofs. They probably think I am a bit crazy for expecting to be able to drive with the hubs locked at highway speeds much less be in 4WD with snow covering the road at the same time.

 

[ab_slack]

No they weren't changed. And yes it is a dana28.

I may have been wrong here. I thought the reference was to the bearing in the dana28 and that is what I was answering. The bearings on the dana28 were not.

Now the wheel spindle bearing was replaced.

I couldn't bring myself to have the shop fix it. With them being so certain it didnt' make a difference, it was just a trust thing since the staked out a position it wasn't important I just felt they would "find" some other problem.

So I pulled it apart today myself and fixed the phasing. I believe I got it right on, but with the jacked up and the tight space it is possible I got it off by one spline but I am pretty confident I got the right one. It would have bee nice of there were only 6 or 8 splines, as that would make it obvious, but I was off by one at one point and thought it was pretty clear.

Fixing the phasing did help quite a bit. I will have to drive it some more. maybe it will loosen up and get worse, but my assessment from one test drive is that it took care of 2/3 to 3/4 of the vibration. Below 50 I didn't notice any real vibration. Before the work today I noticed some low level vibration as low as 35mph. I could hear the additional stuff spinning so was louder, but unline before there wasn't a vibration that just got worse with speed.

I got up to 70mph. I did notice some vibration in the 55 to 65 region but I think this was more a balance/resonance type vibration since it seemed to go away as I got up to 70. So maybe I have to look at front drive shaft balance or balance of the right side shaft.

Again thank you.

 

[alwaysFlOoReD]

Swap front tires for back and see if vibration changes.
Look for out of round tire, broken belts.
Check wheel and tire balance.

 

[ab_slack]

Swap front tires for back and see if vibration changes.
Look for out of round tire, broken belts.
Check wheel and tire balance.

I don't see the vib with hubs unlocked so tend to not think that, but I guess with hubs locked something out of round could add imbalance into the system.

Anyways an easy swap and while tires are fairly new a rotation may be in order.

I also wonder...the spindle seat (the thin metal cup between the steering knuckle and the spindle) was in really bad shape. All rusted and beat up that I thought at the time was going to affect how it sits. I tried to get it back to original position, but not certain. I wonder if that could have affected the alignment a little bit.