How to diagnose a bad front diff?

[Ksat]

Okay, so the grinding could've been there from the beginning..

I'm not sure how much the jack stand test really proves or disproves in your case. There's just a lot less stress/torque put on a bunch of things down there when doing that.

$280 is probably for the wireless version. The wired version, which is better IMO, can be had for about $100. You can find knock-off versions of it for even less. If you're handy, you can build one of your own, too, using one of those cheap <$10 hearing amplifiers sold at Harbor Freight and other places.

 

[derekj]

I have seen bearings (wheel and diff) only make noise when under load - ie - car is driving down the road. If you don't want to buy the chassis ears maybe it is time to take it to a shop. I'm sure a good shop can diagnose the problem within an hour.

 

[DeCaff2007]

Okay, so the grinding could've been there from the beginning..

Yep, probably was. Doesn't explain why the front driveshaft was missing in the first place. We'll probably never know.

I'm not sure how much the jack stand test really proves or disproves in your case. There's just a lot less stress/torque put on a bunch of things down there when doing that.

Agreed. I can do the test again... putting the jack stands on the lower control arms instead of the frame. I'm almost curious to see what difference it would make.

$280 is probably for the wireless version. The wired version, which is better IMO, can be had for about $100.

Again, correct.


Aside from all that, we found affordable wheel bearings on Ebay as opposed to Rock Auto and their extortion. I didn't like how those bearings (actually hubs) looked from the beginning so they were going to get replaced anyway. Now, it will eliminate (or prove) those as the cause of the grinding.

Also, I read somewhere that wheel bearings are likely to wear out first, then the ball joints give up the ghost after that. Well, I JUST REPLACED all 4 ball joints. So the wheel bearings seemed like the next logical step, no?

 

[Ksat]

What's RockAuto trying to extort? I've found they love to play games with their shipping prices, but I still sometimes order from them, esp. when they have closeout specials.

I think the lower ball joints tend to be the more complained about part here out of the 3 you mentioned Re-greasable replacements on those are a fan fave. I don't think the wheel bearings are particularly problematic compared to other vehicles.

The bearings are easy enough to replace on the lib, at least as far as bearing replacement jobs go. Note that the hub bearing is held on by internal Torx bolts. I don't recall the size, but it might be helpful to have a set of sockets on hand to remove them. A 12 point socket might also get it off.

Good luck,

 

[duderz7]

E14, you can buy a set cheap at harbor freight. Don't cheap out on hubs, unless you want to do them again in a short time. Timken or skf are the preferred by most.

 

[DeCaff2007]

What's RockAuto trying to extort?

I was just trying to be funny/sarcastic.

 

[DeCaff2007]

Ok I have a small update here, and possibly the answer to the grinding.

The wheel hubs came in today and those were an easy peasy install. I thought, hey, everyone has suggested wiggling the front diff yoke and/or taking the cover off to check the internals.

So, I did just that. If I grab the yoke and try to wiggle it up and down, it's PRETTY TIGHT. Side to side/in and out produce the same result. If I turn the yoke in either direction, however, it's hard to describe just what's going on there. It almost feels like I'm trying to stir a pot of REALLY thick soup. I don't know how else to explain it.

Well, I got curious and took the diff cover off. Someone has changed that fluid VERY recently. I didn't see any metal or silvery sludge. In fact, it looks like it just got poured from whatever container it was in.

Then, I turned the TIRES and watched everything moving inside. The spider gears, ring gear, and pinion gear all look worn but shiny. There's no pitting and nothing is broken.

Upon spinning the tires and listening, though, there's a CLEAR grinding noise. It's not loud, but it's audible. I bet it has to be either the pinion gear bearing or one of the chunk bearings.

I've rebuilt more GM rear ends than I can count, so this is nothing new to me, but I'm very surprised that the front diff is put together so similarly to the rear diff. I could likely easily rebuild this rear myself.

I guess it's time to start pricing rebuild kits.

P.S.: I noticed it says DANA on the bottom of the diff case. This is as opposed to what?

 

[duderz7]

It's a dana 30a which has some differences to the dana 30 which is much more common. Some of the items interchange, some do not. When I did mine I pulled bearings and races and then ordered exact same mfr and part numbers. To bad your not closer, I've got a complete diff in the garage.

 

[DeCaff2007]

It's a dana 30a which has some differences to the dana 30 which is much more common. Some of the items interchange, some do not. When I did mine I pulled bearings and races and then ordered exact same mfr and part numbers. To bad your not closer, I've got a complete diff in the garage.

Wow! Google a Dana 30A and it's brings the wiki page right up, SPECIFIC to the Jeep Liberty. I would have never found that. Thanks for the info.

JUST out of curiosity, there, duderz7... If that complete diff is a working unit... I wonder what it would cost to ship to 18201.

 

[DeCaff2007]

Ok last question before we make the decision to replace or rebuild....

Is there anything special I need to know about this 30a? I see ONE rebuild kit available. It's on Rock Auto, part number USA14141. Holy effing expensive!

Aside from that, has anyone seen a video or typed up instructions on the specifics of rebuilding this front diff?

It seems replacing it would be easier and a whole lot less time consuming, but again... I'm having trouble finding one (reasonably priced).

 

[duderz7]

Wow! Google a Dana 30A and it's brings the wiki page right up, SPECIFIC to the Jeep Liberty. I would have never found that. Thanks for the info.

JUST out of curiosity, there, duderz7... If that complete diff is a working unit... I wonder what it would cost to ship to 18201.

Certainly more than finding one at a junkyard... Idaho is quite the distance from where you are. Check out car-parts.com if you don't have wrecking yards near you. To answer your other question. Rebuilding is quite the chore even if you have the special bearing pullers and a press. Remove and replace is definitely easier. And if they try to charge you for the price of an axle at the yard just tell them, "ok, I'll go ahead and go grab the axles and hubs then". I did that and ended up paying the diffrential price which normally is just the internals. Post a picture of yours with the cover off so we can see. Also look for excessive play in the spider and side gears.

 

[DeCaff2007]

Certainly more than finding one at a junkyard... Idaho is quite the distance from where you are. Check out car-parts.com if you don't have wrecking yards near you. To answer your other question. Rebuilding is quite the chore even if you have the special bearing pullers and a press. Remove and replace is definitely easier. And if they try to charge you for the price of an axle at the yard just tell them, "ok, I'll go ahead and go grab the axles and hubs then". I did that and ended up paying the diffrential price which normally is just the internals. Post a picture of yours with the cover off so we can see. Also look for excessive play in the spider and side gears.

There's plenty of yards around here, and I have no problem pulling the parts myself. I'm just leery about finding a front diff and oh look it's just as bad or worse than the one I have now lol.

Alright, I'll get the to the pics here today. Gimme some time.

 

[u2slow]

I find buying the individual rebuild pieces cheaper a la carte. Kits often cost more because they dont sell the same volume.

Also be sure to get the housing end bearings. Dont think theyre part of any kit.

https://www.amazon.ca/Yukon-YB-AX-007-Bearing-Differential/dp/B00EHKQ4R2

 

[DeCaff2007]

OK, pics and a vid as promised.

Like I said, the spider gears, ring, and pinion gears are worn, but ok.

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Slightly better shot of the pinion gear:

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Now, let me explain what's going on in this vid. Front the start, until about the 20 second mark, I'm trying to spin the diff (with my right hand) via the pinion, where the front driveshaft would connect, while trying to hold my phone with my left hand (and bracing myself against the frame at the same time lol). The grinding can be heard during those 20 seconds.

From :20 to about :24, I'm checking the backlash/checking for play anywhere. Seems normal really....

Lastly, at :28, I'm trying to slide over enough to spin the PASSENGER side tire with my knee. I still hear the grinding.

OK! Let's see what suggestions comes out of this?

VID:

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[u2slow]

Take the axle shafts out so you can prove the noise, drag, etc is the diff bearings or not.

I can almost promise you the outer bearings and splined-coupling to the passenger shaft is what wears out first.

 

[DeCaff2007]

Take the axle shafts out so you can prove the noise, drag, etc is the diff bearings or not.

I can almost promise you the outer bearings and splined-coupling to the passenger shaft is what wears out first.

Ah! So it's not my imagination and that slight-but-present grinding should not be there, yes?

Ok, I can do that. It's going to be a few days, but I can do that.

I'll report back what I find.

 

[DeCaff2007]

So, just to be clear, I'm taking the axle shafts out and test driving WITHOUT the front drive shaft, correct?

 

[u2slow]

So, just to be clear, I'm taking the axle shafts out and test driving WITHOUT the front drive shaft, correct?

Sure. Then even try again with the driveshaft in, in 4Hi. (Plug off the holes in the diff to keep gear oil in.)

Im pretty sure youre going to find the obvious problem on removal of the axle shafts.

 

[DeCaff2007]

Sure. Then even try again with the driveshaft in, in 4Hi. (Plug off the holes in the diff to keep gear oil in.)

Im pretty sure youre going to find the obvious problem on removal of the axle shafts.

Ok thanks for the advice. My whole day tomorrow is clear and I've even cleaned out the garage so I have ample space in there if need be.

Stay tuned...

 

[DeCaff2007]

Hmmm.. I pulled out the passenger side CV axle (WAY easier than I thought it would be!) and found metal shavings on the splined side. Do I even need to tear into the driver side, or even drive w/out the axles for that matter? I'm pretty sure there's more shavings somewhere inside the front diff.

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