what would cause the front diff to overheat?. popped off the diff cover and the fluid is burnt, there is a goldish tint to the fluid (metal) when I had it in 4x4 the front still locked & pulled like it should so I'm a tad bit confused.

should I clean it up, dump fresh fluid in it and see how it runs? cant be any worse than it is already, what do you guys think?

 

I guess if the bearings were not set correctly they would create heat and pressure and destroy themselves

 

the goldish tint would be copper. so oh yeah,I second that you may have bearing problems or the shim pack in the diff.

 

and I'd assume a bearing problem could be started by having most of the diff fluid pushed out of the vent tube...? still not sure why that happend. any thoughts? the diff fluid is burnt, stinks big time. I'm thinking at this point there is not much I can do since I dont know what the hell i'd be doing with the diff (never worked on them) so I'm thinking I'll spray it down with a solvent and clean it up as much as possible then seal & refill it. any thoughts?

 

I'm gunna third the burned bearings. . .the backlash probably was not set properly.

 

I take it that you saw the oil coming out of the vent tube? If so, the oil had to be way over full. Even then, most of the oil should still be in the diff. Now if the bearing went out and overheated the oil, then the oil might come out of the vent. Either way it had to be filled to the max./ If it was mine, I'd be checking the bearings and diff. I would not drive it to cause further damage. Paying a little to fix now is better than paying a lot later.

 

Besides the metal particles, was there other junk or water and is the ring gear fine? If the bearings went bad and heat was produced, it would create pressure and the oil would take the easiest route out. Were different gears installed in the truck before you got it? Is it leaking oil from the pinion area or making funny noises? You could clean it out well (with kerosene or diesel), make sure the vent line is not plugged and see what happens

 

there was still oil in the housing and I'm not 100% sure how much came out. the other Dak I had... had a bad bearing in it and did not burn the fluid like this. when I drove it earlier today, there were no noises what so ever from the front end.

thinking about it more... the only thing that comes to mind is that the transfer case went bad, putting 100% power to the front diff on dry pavement. I think a call to west coast diffs is in order tomorrow. they're the ones who did my gear swap on my 2nd gen truck. the good thing is that there are no chunks of any sort in the bottom of the diff.

 

Even if the front diff was getting all the power, would that matter? How would it be any different from 2 hi where all the power goes to the rear? I don't think that is the issue with it because in any case it should not produce enough heat to burn the oil.

Edit: I reread your post-if it was in say 4 hi on pavement with all the wheels getting power there should be some wierd behavior when you turn-it kind of sounds and feels funny when you turn.

 

yup, that is what was happening... the TC is a full time TC with something like a 48-52 split of power front/rear. the rear diff is posi rear so there is only 1 drive wheel until traction is lost. both front wheels were being driven at 100% of the power. when I had the front driveshaft in I was able to move and had front binding in the AWD mode (remember 2L, AWD & 4H are the options). yanked the front DS and then I had no movement in AWD. This is telling me that all the power was going to the front. Also keep in mind that the previous owner had a 31" tire and 3 29" tires on there which will take out the TC.