Need Help - Have clunk in front diff and alignment issues

[cbenowen]

I have a clunk or more of a metallic pop sound coming from the front end every time I shift into drive. I'm convinced that it's the front diff mount. So I took it to the dealer today and they told me that it's coming from inside the front differential. Any body know what it could be?

I have looked at "The Official Clunk Thread" and haven't found an answer.

Also, I have an alignment issue that I can't seem to fix. Dealer said I need a new steering rack to fix it. Any ideas if this will really fix it?

 

[arcteryx]

I didn't think dealers did alignments. I would take it to a firestone (get the lifetime one, it's just under $200 after coupon) and get it done and see what they say. They should give you a printout of the specs before and after.

 

[lead62]

How are your inner and outer tie rods? Ever replaced the upper/lower ball joints in front end? Some here have tightened the bolts for their steering racks, replaced inner tie rods along with rack bushings and pop went away. Any movement in the rack? How are u-joints? How many miles? How is the input shaft on front diff? Any movement? Have you been able to pry on front diff and see movement in mounts?

 

[cbenowen]

How are your inner and outer tie rods? Ever replaced the upper/lower ball joints in front end? Some here have tightened the bolts for their steering racks, replaced inner tie rods along with rack bushings and pop went away. Any movement in the rack? How are u-joints? How many miles? How is the input shaft on front diff? Any movement? Have you been able to pry on front diff and see movement in mounts?

I have 208,000 miles on it. I haven't looked at the inner and outer tie rods yet. Dealer said tie rods have a lot of play and that's why it cant be aligned. The steering rack doesn't make any noise and doesn't leak. Upper/lower ball joints have not been replaced yet. The u-joints seem fine to me....not much play in the drive shaft. I can see movement in the front diff mount that comes off the pumpkin when it is shifted from reverse to drive. Dealer swears the noise is coming from inside the front diff.

 

[arcteryx]

I have 208,000 miles on it. I haven't looked at the inner and outer tie rods yet. Dealer said tie rods have a lot of play and that's why it cant be aligned. The steering rack doesn't make any noise and doesn't leak. Upper/lower ball joints have not been replaced yet. The u-joints seem fine to me....not much play in the drive shaft. I can see movement in the front diff mount that comes off the pumpkin when it is shifted from reverse to drive. Dealer swears the noise is coming from inside the front diff.

That would have been good information to put in your original post. In that case, get the TREs replaced, start there and see how it drives before spending more money and time. They are not too expensive to replaced. Normally racks leak and necessitate replacement. I would be suspect of that being the cause if yours doesn't leak or make noise. It's a lot of labor to RnR the rack, which means $$$ for the dealership.

If the dealer says it's the diff, the only way to know what's going on with that is to crack it open and see. Having the dealer do that will be pricey. Is there not a good indy mechanic around that you can take it too?

 

[cbenowen]

I didn't think dealers did alignments. I would take it to a firestone (get the lifetime one, it's just under $200 after coupon) and get it done and see what they say. They should give you a printout of the specs before and after.

I've had the alignment done 3 times over the past 6 months at Tire Kingdom and the tires moved around too to see if that helped. Each time they say its aligned.

 

[lead62]

You should be able to replace both inners and outers without getting a new rack. Should not be that hard to replace the front diff mount as it is required to be moved for diff drop. Just $$$$. Did you drop your diff when you did a lift? There are a lot of ball joint replacement threads on here as well if the inner/outer tie rods don't solve the alignment issue.

 

[cbenowen]

That would have been good information to put in your original post. In that case, get the TREs replaced, start there and see how it drives before spending more money and time. They are not too expensive to replaced. Normally racks leak and necessitate replacement. I would be suspect of that being the cause if yours doesn't leak or make noise. It's a lot of labor to RnR the rack, which means $$$ for the dealership.

If the dealer says it's the diff, the only way to know what's going on with that is to crack it open and see. Having the dealer do that will be pricey. Is there not a good indy mechanic around that you can take it too?

Thanks for the suggestion. Should I get both inner and outer TRE's replaced? I have a good mechanic for the diff that I can use. I figured the dealer would be way expensive for that.

 

[arcteryx]

I've had the alignment done 3 times over the past 6 months at Tire Kingdom and the tires moved around too to see if that helped. Each time they say its aligned.

What do you mean by "the tires moved around too"? Three times in 6 months? yea something is wrong. I am surprised they would not find the problem. Did they give you a printout of the before and after, like this? If so, what are the numbers?

I mention Firestone because 1) they have a lifetime alignment and 2) the machine they use does a 4 wheel alignment, the brand of it escapes me, perhaps someone can chime in.

 

[arcteryx]

Thanks for the suggestion. Should I get both inner and outer TRE's replaced? I have a good mechanic for the diff that I can use. I figured the dealer would be way expensive for that.

I would. More than likely, those are the originals so at 208K, it is due for sure. (note to self, I need to do mine too ) If you have an indy, I would let them do it all. Most of the time, those shops are OK with you bringing your parts too. So you can get them from @beno , take them to them and have them install them. This way you are not paying a markup on the parts and you are ensured that OEM parts will be used. (assuming they actually put them in of course).

 

[cbenowen]

What do you mean by "the tires moved around too"? Three times in 6 months? yea something is wrong. I am surprised they would not find the problem. Did they give you a printout of the before and after, like this? If so, what are the numbers?

I mention Firestone because 1) they have a lifetime alignment and 2) the machine they use does a 4 wheel alignment, the brand of it escapes me, perhaps someone can chime in.

The last time the tire place did an alignment they swapped the tires from side to side to see if that effected it. Maybe I will find a firestone and see if they can get it right.

 

[loganbrew]

Replace only the tie rods or upper/lower ball joints showing evident slop. Your mechanic can tell you which. Inner TRE's on steering rack commonly have slop at your mileage, even if you are predominantly doing pavement miles (no wheeling). @240,000 I replaced the whole rack due to inner tie rod play and shot bushings, even though rack was leak free. Also used polyamide replacement bushings and now the hundy handles like a dream. The rack/bushing replacement also stopped the random traction control engagement and cruise control kicking off during gentle bending curves.

At just over 200,000 miles I finally determined the source of my front end clunk. For at least two years the clunk got progressively worse/louder when shifting to reverse/drive. I assumed it was front diff and an inevitable $$$ repair bill coming, but to my (pleasant) surprise it was just fatiguing splines on the front drivers hub. One day the splines let go with a horrible grinding, but it was also more obvious the diff was NOT the source of noise. I pulled the hub (located just behind the front wheel center cap) and saw where a perfectly healthy set of splines on the CV shaft had completely chewed the splines on the hub - after being pounded (back and forth) for years when engaging drive/reverse. Picture shows smooth ID on left hub, only because I had a machinist at work turn it on a lathe so I could keep the LC on the road until my new parts arrived. The right-side hub is the passenger side I replaced, even though it was otherwise healthy.

Bottom line... ask your mechanic to pull the hubs - it's a quick first check before digging into the diff. If there is any movement between the mating parts then replace. The parts are cheap and for me eliminated the clunk without reoccurrence for past 50k miles.

 

[loganbrew]

Ahh... a youtube video here

Your mechanic can just pop off the cover piece on the hub to expose the axle/hub interface. Yours won't spin, but with someone on the brakes while shifting to drive/reverse a watcher can look close for movement between the splines, which won't be more than a fraction of a millimeter.

 

[2001LC]

This is amazing the Dealer did not check this, Wow. Or may be they did. I not use them again.

 

[cbenowen]

Replace only the tie rods or upper/lower ball joints showing evident slop. Your mechanic can tell you which. Inner TRE's on steering rack commonly have slop at your mileage, even if you are predominantly doing pavement miles (no wheeling). @240,000 I replaced the whole rack due to inner tie rod play and shot bushings, even though rack was leak free. Also used polyamide replacement bushings and now the hundy handles like a dream. The rack/bushing replacement also stopped the random traction control engagement and cruise control kicking off during gentle bending curves.

At just over 200,000 miles I finally determined the source of my front end clunk. For at least two years the clunk got progressively worse/louder when shifting to reverse/drive. I assumed it was front diff and an inevitable $$$ repair bill coming, but to my (pleasant) surprise it was just fatiguing splines on the front drivers hub. One day the splines let go with a horrible grinding, but it was also more obvious the diff was NOT the source of noise. I pulled the hub (located just behind the front wheel center cap) and saw where a perfectly healthy set of splines on the CV shaft had completely chewed the splines on the hub - after being pounded (back and forth) for years when engaging drive/reverse. Picture shows smooth ID on left hub, only because I had a machinist at work turn it on a lathe so I could keep the LC on the road until my new parts arrived. The right-side hub is the passenger side I replaced, even though it was otherwise healthy.

Bottom line... ask your mechanic to pull the hubs - it's a quick first check before digging into the diff. If there is any movement between the mating parts then replace. The parts are cheap and for me eliminated the clunk without reoccurrence for past 50k miles.

View attachment 1218130

I just checked the front hub flange and there is no movement. Thank you for the suggestion. As far as the Steering rack goes, I'm probably just going to replace the whole thing. But only after I figure out the front end clunk.........not sure how much $$$$ that will be.

 

[cbenowen]

This is amazing the Dealer did check this, Wow. Or may be they did. I not use them again.

The dealer did no check. They insist that the noise is coming from inside the differential.

 

[lead62]

Rack replacement usually is right at 1500 for someone else to do it. Might be worth just changing outer tie rods unless your rack is leaking. They don't automatically change them when they do the rack.

 

[loganbrew]

The dealer did no check. They insist that the noise is coming from inside the differential.

Well they could be right, after all they're looking right at it. My first assumption is always that the weak link lies outside the diff though. I assume you checked BOTH hubs already, so check the CV joints and don't dismiss your initial hunch with the front mount. Sounds like you've already been underneath it with the rear skid plate removed to see everything clearly. Chalk the rear wheels and again with a helper on the brake and shifting between drive and reverse look at everything for QUICK movement from slop in a joint, front/rear mount bushing, etc. The clunk is from slack somewhere between the input to the front diff and the front wheel hubs. Even though the slack might be outside the diff, when that slack gets taken up (when power is applied) the clunk could still sound like it coming from the diff due to all the system's momentum stopping suddenly. If you cannot see where that slack is getting taken up on the outside, unfortunately it may very well be inside...

And for a sanity check be sure to disengage the center diff from the console button to only send power to the rear. If you still hear the clunk then it's not up front after all. Not that I don't trust you of course, just the trained thinking of a man who's trouble shot a lot of things in the completely wrong direction following a boneheaded initial assumption

Good luck!

 

[cbenowen]

**UPDATE**

Dealer was incorrect about the front end clunk. It was the front diff mount that comes off the diff cover, like I suspected. I replaced it today and no more clunk. Glad that's all it was. I cant believe the dealer missed this. Now I just need to replace the steering rack and should be good to go.

Thank you everybody for all the help.

 

[abuck99]

Congrats for figuring out the issue-

Btw, could you post the part number for what you replaced.