Have I damaged my Front Diff

[Sashamil]

Hi everybody,

Since I got my LC there was always a small howling sound which I assumed was a Turbo. In the last year I got my dad driving it and he started mentioning that the sound got louder and louder. Last week I opened front differential oil plug and found out that all my diff oil has turned in a mixture of front knuckle grease and diff oil. Also, there was not much of it left in front diff at all. Looks like it all came out of front knuckle. We did put quite a bit of km in this condition I would assume, and now I am trying to figure how much damaged I might have caused inside front diff. Have I damaged and gears/ bearings How do you investigate this without taking whole front diff apart?

Any suggestions?

Thanks in advance

 

[jertiffauk]

Well if it's all leaking out the knuckle a rebuild is in order. But by draining what's left and filling it with fresh you will know if it fixes the noise or not. Bearings should not be effected by knuckle leak, but could be cause of noise if they are in bad shape. Time to get your grease on!

 

[nukegoat]

Hi everybody,

Since I got my LC there was always a small howling sound which I assumed was a Turbo. In the last year I got my dad driving it and he started mentioning that the sound got louder and louder. Last week I opened front differential oil plug and found out that all my diff oil has turned in a mixture of front knuckle grease and diff oil. Also, there was not much of it left in front diff at all. Looks like it all came out of front knuckle. We did put quite a bit of km in this condition I would assume, and now I am trying to figure how much damaged I might have caused inside front diff. Have I damaged and gears/ bearings How do you investigate this without taking whole front diff apart?

Any suggestions?

Thanks in advance

The howling noise from a diff that's running dry will correspond with vehicle speed, usually. Usually it's described as more of a whine as well.

Your inner axle seals are likely destroyed based on what you're describing. The bad news is that they should be fixed, the birfields may be damaged, and the ring and pinion may show accelerated wear. Bearings may also be in bad shape. Without knowing how it actually sounds and poking at it, it's really hard to say whether that's the case.

You can do some cheap diagnostics for the birfs, but it's pretty much a guarantee that you'll have to disassemble your front axle anyway, so you might as well take off the 3rd member as well and investigate.

Ultimately, the good news is that it's fixable with available replacement parts and although greasy and time consuming, it really is fairly doable even for an amateur.

Since others might say it, I'll be the first to suggest that given the lackluster performance of your engine, I'm surprised you assumed it was turbocharged.

 

[Cannon88]

Since others might say it, I'll be the first to suggest that given the lackluster performance of your engine, I'm surprised you assumed it was turbocharged.

Turbo diesel. He is in Canada, and he has his rig listed in the sig line.

 

[Sashamil]

I have replaced front bearings approximately 2 years ago. Now, I did do it my self and have followed step by step instructions from a post here. I am assuming I have done things correctly, but on the other hand I was learning as a went, so I might have done something wrong.

I understand now that I have change seals, and rebuild a front knuckle assembly. I will probably take apart the diff and take a look.

The sound I am getting goes away as soon as second as I lift my foot of the pedal. The loudest whine/howl ( sound is constant ), i get between 60 km/h -120 km/h
There is no sound coming when I am off the gas, so it is not wheel bearing.

 

[Sashamil]

It is a Turbo Diesel. At the beginning, it was a quite whine, and as I never owned a engine with a turbo before I was guessing it was the Turbo.

 

[Redhookdave]

Maybe it's an exhaust leak?

 

[Kaveeks]

It's probably the pinion bearings that are bad because of the moly/oil mix and leaking seals.
At least that's what was up with mine. I had the axle and front diff rebuilt and the old pinion bearing were really rough.

 

[Tools R Us]

It hard to say if anything is damaged? The test would be to drain it as well as possible, fill with cheap gear oil, drive it and see. Check the knuckle grease level, very likely low/empty, needs to be about 1/2-3/4 full with moly grease. If it runs without noises, go a couple of hundred miles and drain/fill again to flush more of the mess out, may have to do this more than once. Pay attention to any metal on the magnet, will give a clue to condition.

It is normal for the knuckles to push some grease out. They don't have breathers, the axle does, so with each heat cycle, the expanded air has to go somewhere, often burps into the axle, taking grease with it.

This is why axle maintenance is important. If the gear oil isn't changed, the grease in it will thicken it, causing heating, reduced lubrication, etc. I prefer to run the cheap gear oil and change it every year or two, depending on how the rig is used. This keeps it nice and clean, reduces issues.

 

[CJF]

The sound I am getting goes away as soon as second as I lift my foot of the pedal. The loudest whine/howl ( sound is constant ), i get between 60 km/h -120 km/h
There is no sound coming when I am off the gas, so it is not wheel bearing.

It's probably the pinion bearings that are bad because of the moly/oil mix and leaking seals.
At least that's what was up with mine. I had the axle and front diff rebuilt and the old pinion bearing were really rough.

Yup: Pinion bearing, not wheel bearings.

 

[Tools R Us]

Unless it's making huge noises, I wouldn't take it apart now, once it's apart it's often difficult to definitively identify the problem part(s). Would get the proper lubes in it and drive, find what all is wrong, go into it with better knowledge of what needs to be addressed.

 

[86tuning]

Unless it's making huge noises, I wouldn't take it apart now, once it's apart it's often difficult to definitively identify the problem part(s). Would get the proper lubes in it and drive, find what all is wrong, go into it with better knowledge of what needs to be addressed.

^^ this is the proper diagnostic process. Put in $15 of gear oil and drive it. It's not possible to break it any further anyways. Any damage done has already been done. Fill with 80w90 or heavier gear oil. Stuff from Walmart or wherever will work fine.

After filling it up, WASH the front end and then monitor for leaks. Find and repair the leaks. If everything is leaking, consider a tear down and repair at that point.

 

[Sashamil]

I will have to rebuild front knuckles as I will have to remove them to change inner axle seals. But before that I will take your recommendation and do few changes of diff oil and try to pinpoint exactly where the noise is coming and see if there is any metal shavings when i drain it. I need to read up more on the how to rebuild it as I will have to it myself, but there is tons of info on here. I just know I will need tons of paper towels, rags and break cleaner

Thanks for everybody's suggestions. Will let you know how it goes.

 

[Tools R Us]

If you are going to pull the axles, might as well pull the diff and inspect the bearings. Pulling the axles is more than half (like 3/4) of the job, would hate to do that twice in a short time.