Groan, shutter, vibration while turning

[LogansPathy]

Hey, guys! I searched the forums for answers and they were across the board from bushings, to shock absorbers, to diff fluid, to prop shaft stuff so I was hoping that someone who's had this issue specifically might read this and have a more specific idea than the wide range I have so far.

 

 

I bought my 93 pathy in June. Within a couple of days I had this same issue. What it is is a low groaning noise coupled with vibration while I am performing a tight turn (which, with the crappy turning radius our trucks have is just about every turn that happens in city limits off a major highway). I believe the noise is coming from the rear end.The 4wd is not activated. I have factory automatic hubs. I do have LSD and in June changed the fluid and made sure to put in the LSD additive and it seemed to take care of the problem. Then I drove it from California to Texas and all was good until the beginning of September when the noise gradually started coming back.

 

So, I checked the fluid and it's fine, even added a little for peace of mind and added some more LSD additive, mainly because I have a small leak at the seal where the prop shaft goes into the diff (but not all of it, because the container warns not to over treat). Putting in more additive seemed to make a small difference, but not for long. A little over a week ago I drove from Texas to Seattle and now the noise is as bad as it's ever been. Lots of tight turns here, though, which I suspect is accelerating or further exposing whatever the issue is.

 

Now, I have about $200 to my name, no place to work on my truck (though I could probably find a place to change the diff oil again, though I'd rather not waste $50 plus doing it if it's not the issue), it rains here A LOT and I'm quite concerned that perhaps sooner than later the rear end will lock up and leave me stranded, which would be a death blow for me. At this point, I don't know if I can get away with driving it the way it is for a few months until I can get some cash together, or if I should try to part it out (only 137k on the damn thing!) so I can get money for something else. I love the truck, have invested a bit of time and money into it already, and it has served me well, but if the rear diff locks and the truck is towed, I'm screwed.

 

 

Any suggestions? Thanks in advance!

[Slartibartfast]

Does sound like the LSD is going out. An oil change might buy more time, but given how short a time your previous one lasted (I'm assuming you didn't do water crossings or anything that would've gotten water in the carrier), I doubt it would work for long. I've seen pictures from a rebuild where the metal bits between the clutches (or was it the spring bit?) were all busted up, but I don't remember if they were having noise issues or just rebuilding to make it grab properly again.

 

I've never had an LSD (or any axle, for that matter) to bits, but it looks to me like the truck would still be drivable even if the clutch assemblies completely disintegrated. If they lock up, then it would act like a welded diff (and some people do drive around with welded diffs), but the ring and pinion should still work how they're supposed to and keep the truck moving. My only concern, and I'm not sure if it's reasonable or even possible, is that bits of the damaged clutches etc could escape the carrier and chew up the bearings or jam the ring and pinion. I've never heard of this being a problem, but never having worked on one, I'm hesitant to say that everything would be fine. Anyone who knows the LSD carrier better than I do want to chime in here?

 

You could probably just swap out the third member (holds the diff and the R&P) rather than the whole axle, which could save you or your mechanic the trouble of dropping the whole axle out and dealing with the suspension. Check if anyone's parting one out it your area, you might get a better deal than you would at a wrecking yard. Also check your gear ratio before buying; under the hood, passenger's rear of the firewall, there's a data plate that'll have HG43 or HG46 stamped on it. Make sure your donor matches.

 

Good luck, and hopefully this helps a bit.

[LogansPathy]

Thanks for the info! I figured some of what you had said, but I'm relieved to hear that it *likely* won't make the vehicle undriveable. I will do some replacement of parts in about 6 months if the truck will last that long. As mentioned prior, I've not had the truck long and having just moved twice and with very limited funds, all I can do is drive it and hope for the best for now.

 

 

 

When I do go to replace the 3rd member (assuming it's just that), does anyone make something new? I hate to get a used one just to have it go bad on me soon after and waste all the time and materials to boot.

[Slartibartfast]

I really haven't heard of a lot of issues with these, apart from normal wear (clutches not grabbing like they should) and the occasional bound-up rear end that goes back to normal with some additive. I think one guy here managed to blow one up by dumping his clutch at redline in low range. A low-miles unit is always a better bet, but I imagine you'd have to try hard to find a bad one.

 

Looks like this site sells new old stock 4.3 rear ends.

[Slartibartfast]

Just remembered, I read once that the disk brake axle shafts won't fit a 3rd member with drum brakes, so unless you're swapping the whole axle, make sure you get a 3rd from the same axle as what you have.