Dark gear oil - regear

[hammerheadfistpunch]

So I have had nothing but trouble with my regear (Nitro 4.56). I had it done about 2 years ago and it had lash and noise. I had the front redone and when they got in there they noticed it was setup all wrong, with wrong carrier bearings and the gear was overheated. The new shop took a long time and worked their butt of to get the new gears in and setup for a trip I was taking, and got it done in time for me to carefully break them in as a drove. I changed the fluid right after my trip with synthetic and just last night I checked it and I noticed that less than a year later the gear oil is dark again, where the rest of the gear oil changed at the same time is still honey like.

I still have lash and noise.

So tell me the deal. Whats the likelihood its just knuckle grease, and if thats the case, should new axle seals have solved this? Is this something other people are having issues with (knuckle grease in their factory setup)?

How do you know if you have a bad setup or if its just the way these high pinions sound (which I have been told).

Any help would be appreciated.

 

[Tedward]

Is the color green, dark green, olive drab green, some sort of green?
If so, it's likely knuckle grease.
There may have been some grease in the tube or you got some in there.
It could take several changes to get it coming out looking new again.
If your breather isn't working right, or even if it is, sometimes grease gets pulled into the oil. Then you have the green oil.
Just changed the oil in the front of mine and it was green. The transfer case oil looked brand new and the back had just a touch of darker color, but still close to new.
I 'think' the color is not a problem.
I'm no help with the noise or lash.
Good luck!

 

[hammerheadfistpunch]

Is the color green, dark green, olive drab green, some sort of green?
If so, it's likely knuckle grease.
There may have been some grease in the tube or you got some in there.
It could take several changes to get it coming out looking new again.
If your breather isn't working right, or even if it is, sometimes grease gets pulled into the oil. Then you have the green oil.
Just changed the oil in the front of mine and it was green. The transfer case oil looked brand new and the back had just a touch of darker color, but still close to new.
I 'think' the color is not a problem.

Breather is clean, and my knuckle grease is dark (not green) so there is a chance its just grease. I will do a drain tonight and let it separate into parts to see what I've got.

 

[ajax1]

Your knuckle grease bleeding into the gear oil makes the gear oil dark or greenish

 

[LS1FJ40]

I can't help you with the lash or noise but I will say that my front diff oil always looks dark. Whether it is from left over moly mixing in or fresh being pulled in.

I've changed my cedar oil every 6 months, at most, since my 92 was new.

The rear and transfer case always look newish.

I always use cheap gear oil and change often.

 

[half k cruiser]

@hammerheadfistpunch another easy check is to pull the outer hub flange from the axle so you can look in at the wheel bearing. See what it looks like in there. For instance, when I did my wheel bearings last I used red grease in them. When I pulled the outer hub a few weeks back the grease was green/grey. I knew right away there was cross contamination.

 

[Sarmajor]

Half K Cruiser,
If you pull the drive flange from the hub (which is what I think you are saying in your post) the cross contamination is between the birfield grease and the wheel bearing grease. It would be very unusual to have the wheel bearing grease contaminated with diff oil. If the axle tube leaks oil into the knuckle the oil generally washes the grease out through the wiper seals and drips onto the wheel and ground.
The usual direction for migration is from the knuckle into the axle tube due to a vacuum forming in the axle tube when it is rapidly cooled driving into a water crossing with defective breathers. The large amount of air in the axle tube contracts and pulls some grease through the axle tube seals. This will give you tinted grease. Even good seals won't stop this if the diff breathers are defective. Extended breathers with small fuel filters on the end are a good fix.

I did mine after the first front axle rebuild that was brought about because when I checked the diff oil it was like green soup. I am still getting tinted oil out of it 150,000 km later.

Can't help with the front diff rebuild but the guy I used is reall good and cheap too. Shipping to NZ might be a bit much.

 

[Cruiserdrew]

IF there is any question about the set up, send it to Zuk (Ken) at gearinstalls.com . He'll post up his work for all to see, and will get it set up tight and right.

I have had good luck with Nitro gears in 4.56 and 4.88.

Regarding the color in the front axle-a couple of ideas. Breaking in gears can itself turn the oil black, both because it runs hotter at first, and because the gears come with a black oxide coating that comes off in the oil when hot.

But if the inside of the axle housing is just dirty from old grease, it can take several changes to get it really clean again so it's a good idea to just use cheap gear oil, and change the gear oil out every 5,000 miles for 2 or 3 changes and then go back to the good synthetic stuff.

THe lash and noise is not right. If the rear was set up like your original front, maybe it's there. But the lash can be anywhere-transfer case, drive shaft splines or the differentials themselves.

 

[half k cruiser]

@Sarmajor I agree that the "usual" travel is from axle into birfield housing, and then out past the wipers. However, once the grease in the birfield has mixed up with the gear oil it is able to flow between the shaft and spindle and out into the hub. I just redid the knuckles in my 97 and both sides were contaminated this way.

 

[hammerheadfistpunch]

IF there is any question about the set up, send it to Zuk (Ken) at gearinstalls.com . He'll post up his work for all to see, and will get it set up tight and right.

I have had good luck with Nitro gears in 4.56 and 4.88.

Regarding the color in the front axle-a couple of ideas. Breaking in gears can itself turn the oil black, both because it runs hotter at first, and because the gears come with a black oxide coating that comes off in the oil when hot.

But if the inside of the axle housing is just dirty from old grease, it can take several changes to get it really clean again so it's a good idea to just use cheap gear oil, and change the gear oil out every 5,000 miles for 2 or 3 changes and then go back to the good synthetic stuff.

THe lash and noise is not right. If the rear was set up like your original front, maybe it's there. But the lash can be anywhere-transfer case, drive shaft splines or the differentials themselves.

I wish I had sent it to zuk from the get go, but I didn't. I will keep my eye on it for a few thousand miles and if its not getting better I know where to go

 

[Tools R Us]

... Whats the likelihood its just knuckle grease, and if thats the case, should new axle seals have solved this? ...

It's normal for there to be some grease migration from the knuckles to the gear oil. Free flowing breathers does help, but still. This is one reason I run cheap gear and change it more often. Grease thickens it out of grade, so IMHO, better to have fresh oil than boutique oil that is expensive to change. If you wheel, changing it more often is good practice, allows for better monitoring of contamination, magnet debris, etc.

 

[hammerheadfistpunch]

It's normal for there to be some grease migration from the knuckles to the gear oil. Free flowing breathers does help, but still. This is one reason I run cheap gear and change it more often. Grease thickens it out of grade, so IMHO, better to have fresh oil than boutique oil that is expensive to change. If you wheel, changing it more often is good practice, allows for better monitoring of contamination, magnet debris, etc.

Thats the gist of my question. is non-contaminated front diff gear oil common?

 

[Sarmajor]

Too true Half K Cruiser and unusual happens here often enough.

As far as non contaminated front diff oil being common, the answer from me would be No. It just seem to be the level of contamination that varies.

At least this is only grease contamination and not water because that is much worse for the hearings and gears.

 

[1973Guppie]

isn't there some noise involved in breaking in new gears? I know I have noticed this after having transmissions rebuilt, over time the noise quiets down alot. I just picked up my 80 today from getting 3rd's w/nitro 4.88's and tc crawler gears installed. The first few miles on the freeway it was loud but then quickly quieted down.

 

[hammerheadfistpunch]

isn't there some noise involved in breaking in new gears? I know I have noticed this after having transmissions rebuilt, over time the noise quiets down alot. I just picked up my 80 today from getting 3rd's w/nitro 4.88's and tc crawler gears installed. The first few miles on the freeway it was loud but then quickly quieted down.

its always been noisy (I would say a 2 to 3 on a 1-5 scale of noisy...most people wouldn't notice but I do), its been about a year since install and they aren't getting quieter. They quiet down a little with fresh synthetic but thats it. I've been told by people I trust that the high pinion re-grears are a little noisier by nature, but its hard to know whats normal and whats not.

 

[Cruiserdrew]

High pinion regears are not noisy. I've done it twice, both quiet.

The gear pattern will tell the tale.

 

[Tools R Us]

Too true Half K Cruiser and unusual happens here often enough.

As far as non contaminated front diff oil being common, the answer from me would be No. It just seem to be the level of contamination that varies.

At least this is only grease contamination and not water because that is much worse for the hearings and gears.

Agree, some moly isn't a problem, it's a common additive in oils, not likely to cause harm, some may even be good? The problem is excessive thickening of the oil. One of the key functions of the oil is cooling, transferring heat from the gears to the housing. When the oil becomes too thick, at prolonged speed, it can be flung away from the gears, not have the contact needed to transfer the heat away. Have seen gears overheated, burned up because of this.

 

[Tools R Us]

High pinion regears are not noisy. I've done it twice, both quiet.

The gear pattern will tell the tale.

Agree, there is no reason that high pinion would be any noisier than any other diff.