maguirre

Hi all,

This morning I drove to work and noticed that the roads were a little slick as we have received a few inches of snow overnight. I engaged the 4x4 (4H) to gain more traction and about 25-30 minutes later I noticed a funky smell inside the car and realized that it was coming from outside the car. I pulled over and dis-engaged the 4x4 to (2H), however the 4x4 green light on the panel did NOT turn off, also I felt the 4x4 had not fully dis-engaged while I drove the truck. I few minutes later I decided to pull over on a parking lot to further inspect the car and noticed that smoke was coming from under the car where the transfer case would be. At this point the 4x4 green light on the panel had shut off, however, the 4x4 still felt engaged.

A few minutes of sitting idling and not moving the 4x4 finally dis-engaged and I was able to drive off normally. Also, the funky smell and smoke went away.

Please confirm that this is a transfer case issue and advise on what to do next. Today was the first time I used the 4x4 in about a year or so.
Did I drive for too long of a drive with the 4x4?
Was I going too fast (max 45 mph)??

I plan on buying gear oil and will check the transfer case for leaks.

Any tips and advice will be appreciated,

TIA,

fierohink

Smoke and burning smells generally aren’t good. However it may be circumstantial in this case.

When was the last time you used 4wd? Has your truck had any previous oil leaks (if any type) or does it currently have any leaks? When was the last time you had your transfer case fluid checked or changed?

First off you need to check the level of oil in the transfer case. There is a filler bolt on the side of the case that gets removed and then you stick the tip of your pinky in and bend it downward and if you hit oil, great, if not… not so great.

If you don’t know the last time your transfer case was serviced, now might be a good time to drain it anyway and refill it. This will give you a better look at the condition of the oil that comes out. If it looks like honey it maple syrup, great!!!, if it looks like driveway and flashing sealant… not so great.

I mentioned circumstantial causes. It is entirely possible that if you haven’t used your 4wd in a long time, and you have had a leaking power steering line, or valve cover, or brake line, etc. that the transfer case itself is just coated in other oils and they were burning off once your transfer case got hot from use. That is an outlier of a possibility, but still a possibility.

in any event, get it looked at.

maguirre

So this past weekend I went under my truck to see what was going on...
I replaced the following: 5spd tranny fluid; transfer case fluid and the front differential fluid.
And this is where I discovered the issue, my front differential was almost empty.
I am leaking fluid where my driver side axle connects to my front differential (see pics).



I can see oil leaking where the axle connects to the front differential.

Please let me know what seals, etc I should be getting to fix issue.

TIA,

Marcelo

Jomoka

It's not all that easy to get to it, but there is a seal pressed into the front differential housing. I've replaced it before on mine when I took the CV shafts out to reboot them.

It's pretty easy to damage the seal when reinstalling a CV shaft - it has to go into the diff pretty straight and level, but the end is heavy and floppy, and doesn't want to behave.

To get to the seal you have to remove the CV shaft, which involves taking the front suspension apart on that side to a moderate degree. Unbolt the LBJ (and rally consider putting a new one on when you reassemble), unbolt the cv shaft from the hub, swing the knuckle out of the way, then you can pop the CV shaft out of the diff. A fairly stout spring clip holds it in place. Then you can see the seal.

It's also possible that the breather is stuck shut. This is more common on the rear axle where the breather encounters a lot more grit, grime, water. But still worth checking - it's at the end of a long hose reaching up to the driver side of the engine bay - down under the intake, next to the exhaust - what looks like a hose ending with a metal cap. That cap should move around easily.

However, it's not a great sign that your front diff got hot and smoky. I would tend to think that some damage was done. It would only get hot and smoky if the bearings were dry, and they heated up as they began to damage themselves. Certainly worth trying to refill with oil and using a bit to see if it 'recovers' or if it's going to continue down the path of turning itself into little grindy metal bits. You might end up needing to swap the front diff.

In which case - my condolences. It looks like it would be pretty easy, but it's actually a pretty big PITA. It's heavy and there is very little room to get it out around the crossmember and engine.

maguirre

Thanks Jomoka,
So I'm going to give it a try and replace the seal. Do know the part number for this seal?

thanks,

Marcelo

fierohink

With the amount of oil leaking from the seal, it’s possible that the oil burning and smoke was coming from exterior leakage.

the smoke didn’t happen until the truck was using 4wd, which would heat up the front diff increasing internal pressure and pushing more fluid out. This would lead more weight to a sticking vent.

Jomoka

Some internal parts are moving when in 2WD - that ADD basically disconnects the passenger side shaft from the diff. So the driver side CV shaft keeps on spinning the spider gears, generally less friction there than in the ring/pinion gears and front driveshaft, so that all mostly stays still. But they need lube too. It is a little odd that little to no ill effects would be noticed in the usual 2WD mode - but it's dry enough to get hot from some 4WD use?

It is worth noting that when I drained and refilled my front diff, I refilled it using what I assumed was the proper technique - filling to the level of the fill plug - same as pretty much every other automotive gearbox/transfer case/diff situation I've encountered. And the next time it got fully warmed up - it was pushing some oil out the breather. Which, like I said earlier, is pretty close to the driver's side exhaust manifold. Could certainly lead to some smoky oil smells.

You'd see oil all over the place around the vent, easy to look and check.

maguirre

Hi guys,

I hope everyone is doing very well and safe in these crazy times....

As you can read in my initial post I have a leak in my driver-side CV joint going into the front differential due to a damaged seal. I had this issue during the winter and have NOT gotten around to it to get it fixed. I have NOT used my 4x4 and have been driving without issues for the past few months. I bought all the parts (OEM) to get this job done now that I have some time since I am home quarantined.
Today, something else came up. I went for a drive for groceries and I noticed that my 4x4 light on the panel began to flicker on and off. I also noticed clicking sounds coming from under my shifter. It felt like the 4x4 wanted to engage and I heard all kinds of sounds coming from under my truck (front end).
Any idea what this could be? Is it related to my CV joint seal issue?
My mechanic is about 25 miles away (highway) so I don't want to drive that distance and risk breaking down.

As always all your help and advice is greatly appreciated.

Take care and be safe,

Marcelo

fierohink

Are the green wheel inductor 4wd lights flickering i.e. random, or are they blinking?

I’m not sure what would cause flickering other than an electrical short somewhere.

a blinking 4wd indicator is almost always a sign of a bad position switch either on the front diff or one of the 4 on the transfer case.

maguirre

The 4wd green light is flickering On and Off... not really blinking.
What about the clicking sounds i hear coming from under my shifter?
I thought it might be just electrical, but I feel like the 4wd wants to engage.
Does this have anything to do with oil levels either in the transfer case (which i replaced in Nov 2019) or the front differential?

Thanks,