Drivetrain Noise Diagnosis

[DirtDonk]

You checked the work of the shop to make sure it was phased properly, correct?

If you go the route of having someone else re-work your old one, then in a practically shameless plug (for price comparison purposes of course), we sell new shafts for $280. Or $330 for the extra HD unit. Factor in shipping of course, but that gives you an idea of what a new one might cost compared to having someone professionally refurbish your old one.

When you were trying to take the yoke off, did you unscrew the threaded cap? Did the shop say what was jamming it up?
And along those lines, do the two halves slide easily in and out by hand when they're assembled?

Paul

 

[Amitchla]

Hi guys,

Sorry for the delay here! I got caught up working on the Mach 1 over the past week.

The driveshaft is correctly phased, yes. Also, yes, it does slide in and out properly, it seems.

The mechanic who “unstuck” the driveshaft said the teeth were partially improperly engaged, which made it very difficult to disengage. Visually, the driveshaft teeth didn’t look damaged, at least.

I disassembled the cardon joint today. The grease inside the CV was more less dry, and upon cleaning it out, there were metal shavings imbedded in it. I’ve gone ahead and ordered the rebuild kit (u joints and CV). I’ll report back when I’ve got those installed to see if that fixes the problem. The u-bolts were also stripped on one side, so I went ahead and ordered a new set of those as well.

And, of course, if I end up needing a new driveshaft (and, anything/everything else for that matter) I’ll be going through WH. Most of the truck seems to have come from there already!

 

[bax]

I was wondering how you were doing on this. If you are finding bad stuff, you are making progress.

 

[Amitchla]

Hi guys,

A couple quick updates on this situation.

I replaced the u-joints, CV in the double cardan, and had the driveshaft balanced. The driveshaft shop also showed me that the slip yoke had play in it and needed to be replaced.

All that to be said, it didn't fix the immediate problem, shifting the potential blame to the transfer case, or the transmission.

I did some more reading around the site, and a couple folks mentioned that a rear output shaft with excessive play could cause something like this. My current thought now that the driveshaft has been excluded would be bearings.

It sounds like it's possible to remove the rear output shaft in the transfer case with the t-case still in the truck. Does this sound like a good option, or should I drop the whole transfer case for a full rebuild?

This is a daunting task for me, and I'd prefer to avoid it if possible, BUT, if it's necessary, then I'll do it.

 

[Amitchla]

ALSO - to add to my current thoughts:

There had been what I thought to be a minor leak from the transfer case since I got the truck back from the shop. It seemed to be coming from the speedometer cable area, so i unscrewed it, reinserted, and tightened it down.

Earlier this week I went to check the fluid level on the transfer case (to verify the mechanic's work), and it was about .5 to .75 quarts low. After refilling, oil was more less pouring out the front output shaft seal.

My thought is that driving the truck in FWD may have accelerated a slow leak that was already occurring from the front output shaft seal, and that the low fluid levels could have caused something in the rear output shaft area (the "top" of the tcase) to go bad, since the oil is only splash transferred.

 

[Amitchla]

Followup on this topic:

I’ve sent the rear output shaft housing out to Advance Adapters to get rebuilt, and I’m waiting to hear if there’s anything blatantly wrong with any of the components.

I (finally) removed these front output shaft casing today. The seal is clearly completely shot, which makes me wonder when this Dana 20 was last rebuilt. Pic attached.

Also, noticed some small shiny bits draining after I removed the front casing, so I pulled out the drain plug. There is (to me, at least) a lot of metal shavings on the drain plug (pic attached). I also drained the remaining oil into a jar to see how much metal is present. I’ll update after it sits.

 

[Amitchla]

Update on this, months later:

I installed an NV4500 over the last few weeks. This included, of course, new clutch, adapter kits from Advance, as well as having the extreme output shaft case rebuilt by Advance. Driveshafts have been rebuilt, resized and balanced.

I drove the truck for the first time yesterday, and, low and behold, the noise is still there. At this point, I can’t figure out anything else that could be the issue, aside from the rear end.

To revisit, the rear end is a newly installed Truetrac with maybe 100 miles on it.

I’ve contacted the mechanic who installed it, so hoping that, if it is indeed the rear end, he’ll replace it.

 

[DirtDonk]

Well hell's bells! Thanks for the update, but that's not what we wanted to hear!
Figured you had it nailed down with all the work you did.

You're sure you're in 2wd, correct? They do make a lot of gear whine in 4wd, so figured I'd ask.

You checked all around during the work to make sure that nothing is touching anything else? Meaning no shift levers or driveline bits are touching any sheet metal of the body?

Is it loud enough to get a video of it where we can hear it?

Paul

 

[DirtDonk]

Wait, I see a reference to videos. Don't remember watching them, so will go back and check them out.

paul

 

[sprdv1]

Update on this, months later:

I installed an NV4500 over the last few weeks. This included, of course, new clutch, adapter kits from Advance, as well as having the extreme output shaft case rebuilt by Advance. Driveshafts have been rebuilt, resized and balanced.

I drove the truck for the first time yesterday, and, low and behold, the noise is still there. At this point, I can’t figure out anything else that could be the issue, aside from the rear end.

To revisit, the rear end is a newly installed Truetrac with maybe 100 miles on it.

I’ve contacted the mechanic who installed it, so hoping that, if it is indeed the rear end, he’ll replace it.

Best of luck.....

 

[sprdv1]

Wait, I see a reference to videos. Don't remember watching them, so will go back and check them out.

love our pics and video

damn Monday came too quick

 

[bax]

almost sounds like a "slinger" spinning up on a shaft.

 

[Amitchla]

Bax - huh, interesting. That would be under the diff yoke, on the pinion shaft? That’s what I think I’m discerning from the diagram I’m looking at.

If that’s the case, incorrectly installed/torqued pinion, assumedly?