rear axle overheat | Page 2 | Ford Explorer Forums - Serious Explorations

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rear axle overheat

Ahhhhhhhhhhhhhhhhhhhhhhhhhhh okay well this whole time these dudes are trying to teach you that something must have gone wrong when you rebuilt the diff and setup the gears to get temps that high. Now we are finding out that this rear axle likely NEEDS a rebuild.
Is there any play in the pinion? Up down or side to side? With the truck in N grab the driveshaft right at the rear pinion yoke, see if there is excessive play. Rotational play is okay, but any in and out or up and down is not okay
 



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i wont be able to check it til this weekend since i have an F150 in the garage atm with the dash taken apart for the heater core replacement. but as soon as its free i will check that and see.
 






I get that for sure!! I have 3 bays in the shop and about 27 projects to fill them with
Most F150 use a 8.8 axle also, so here is a good chance to compare the play in the f150 pinion to the play in the sploder
 






ok after finally getting the f150 out i took the pumpkin apart on the explorer and there is no/little freeplay on the pinion

it also stinks rly bad like someone took a heavy **** and didnt clean it up but thats expected with burnt oil

could the bearings that in the diff be the cause of it overheating? or the lack of freeplay be the cause?
 






I think this is probably a job that’s over your head. Setting up gears takes some feel and know how. Calling a fluid change a “rebuild” tells me you don’t have these skills.

A pinion shouldn’t just get tighter. As the wear it should get more slack in the gear mesh. Something has failed.

If you have access to a pick and pull kind of scrap yard I’d price a complete axle. They alway have a few second gens laying around. If you have your pick get one out of a 4.0, just make sure your gear ratios match.
 






im not going to just go to a junk yard and get a new axle plus im not interested in ur opinion anymore since u have been nothing but insulting my intelligence from the start.... i want to learn more about doing this work so when i do have someone come in that needs something like this done i will have the experience and knowledge to do so which is why i am doing this on my own suv and with that said instead of saying go get a new axle why not just talk to me about how to find the cause of the damage and what needs to be fixed so i can learn how to do this. if i actually thought i couldnt do the work i would have taken it to a dealer or an auto shop to have it done. im a mechanic and want to understand parts i have not been trained in....and this is one of the areas im not trained in nor is body work since i want to run a proper shop with more options this is the best way to learn it without damaging someone elses car
 






So you plan on charging someone for an auto service on something you’ll successfully do once without any training? Sounds like a place I’d want working on my vehicles.

If you think a fluid change is a rebuild, and you CLAIM to be a mechanic, you really need your intelligence, and title, questioned.

There’s a reason differentials have shops that only do them. They are highly specialized difficult things to work on. It’s incredibly difficult to diagnose over the internet, especially if the information given is piss-poor at best.
 






The axle bearings are the weakest link, those should be replaced at any good axle service interval, 40k-100k miles etc. Those are cheap parts and relatively easy to change, about $15-$20 for an axle seal and bearing. Do those if they haven't been yet.

What is the temperature at each housing end(exhaust has no notable effect on that area), each of the brakes, and the center area? If kept well with maintenance, the center diff/bearings etc, should last the life of the vehicle. When the center section gets too hot or has issues, that usually means new pinion bearings and setting up the gears, which is the high skill level an special tools job(not for any amateurs(and I haven't done it myself yet)). That's the part which good shops charge $200 or more for, it used to be $100 here 20 years back.

The axle tubes in the 8.8's are pressed into the center housing, they are rarely perfectly centered, and can rarely become loose or too far off center. If you cannot identify the issue easily, I'd suspect the axle tubes being crooked, the axles being under pressure(will hurt the bearings the most) while spinning.
 






hm ok so it could be all the bearings that have worn out from how much heat it has been making. if replacing those help i will look into ordering the parts. the pinion doesnt have any/almost no freeplay so the diff should still b ok. if its the bearings it shouldnt b too hard to remove the axles and replace all the bearings in the tubes since the whole axle tubes and pumpkin r all hitting over 300
 






The high heat is bad for all of it, but the diff/pinion/center section are a next level task, hope for just the axle bearings. Pull the cover and carefully look over the center section, look for and feel for any excess wear, coloring, noises etc. Normally, that ends up looking fairly well, smell is nothing/normal, so you do the axle bearings and inspect the axles(bearing surfaces). If everything feels okay and things line up, fit well etc, service the axles/bearings/brakes, and put it back together with top quality gear oil(Amsoil Severe Gear 70w-140 is the best IMO).

That has kept all of my many Ford 8.8's in fine condition for over 600k miles. I've avoided having to mess with a diff, or gears, which is a big level if you have to get into it. That's why a new(used) rear is often selected, to avoid that rebuild of the diff.
 






well trying to check all that will be difficult since its an AWD so i either have to get all 4 tires off the ground or take the driveshaft off so that i can get the gears to move around. i did get a smell when i first opened it up and it stank really badly from the burnt oil which smelt like someone taking a heavy **** and not cleaning up..... i dont know when i will be able to take the whole axle assembly apart since its winter and no heater in the garage.... plus im limited on my time away from home i live in tx and im visiting atm in sd which also sadly limits my funding so may just close it up again and put it on the side until i have more time to fully dismantle the whole thing and take a look which sadly may take a yr or two b4 i can do that and just transport it on a trailer to my own property....
 






The axle bearings and seals should be a two hour job if you have the bearing puller kit and slide hammer ready(rent those for free). If the axle is an LS diff, then R&Ring the strong spring in the middle is a bit tough sometimes. It can be done in a garage easily if there is space for each axle to come out. You do not need the driveshaft to move to check the diff, as much as we are suggesting(a general visual inspection, not a precise measure the run out specs deal). When one axle is removed, all of the gears will move except for the pinion and the other axle, so don't quickly grab things and spin them. The gears will come apart if you do it without carefully doing it and knowing how the components go back together.

I need to do that with my last 98 AWD truck, but haven't yet while needing it daily, and knowing the parking brake pads are gone and need to be done also.

I'm sure that there are several threads here that show pictures and descriptions of how to do the axle bearings and seals etc. That's not that complicated, and tons of members here can and will help for any details you might run into. I wouldn't drive that a long distance if it really is getting that 380* hot, that might cook the ring and pinion gears, plus bearings, on a long trip. Those may already be hurt, but don't push it if they might not be.
 






i wasnt going to drive it all the way there i would load it onto a trailer and tow it down using the F150 i just finished so that there is no more stress on the gears plus we have decided to just close it back up and reoil it again and park it in the yard until its down at the other property.... also it does have a spring in the middle of the gears and pinion so im guessing thats the LS diff u mentioned.
 






Yes, that large spring is in the limited slip differentials(letter axle code on the VIN tag). That come out easily with a pair of Visegrips. But to put it back in, I like a big chunk of wood to put against it, with the spring poised to go back in. Hitting the bare steel spring does not work well at all, the spring absorbs the impact and recoils back out. A large piece of word will take the force of a baby sledge, and its mass will help a bunch to psh and hold the spring into place. It usually will go in half way in one or two tries. Then it's easy to carefully tap it the rest of the way in. I need to take pictures of that when I get to doing mine the next time. I haven't seen that pictured before, just described rarely, many years ago.
 






have you checked tire pressures?
The factory limited slip slipping can generate massive amounts of heat
 






Depending on the grade of oil, 380 probably isn't too far from the flash point. Getting a junk yard axle, then using it learn how to replace parts and work on isn't a bad idea.
 






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