Leaking front differential

[Ursae_Majoris]

2002 Isuzu Axiom, same differential as Isuzu Rodeo.
Noticed that my differential was wet a couple of years ago. Did not think much about it, since dealer spilled oil past the filler cap and some spilled down on the undercarriage.

Noticed it again last week. Put a cardboard box underneath. So far it dripped about a dime-size worth of fluid in 3 hours.

Dealer replaced fluid earlier this year. Before I moved out of state, I had them look the car over, and they did not notice anything.

I could not see much underneath, I need to take crash plates off before I can crawl underneath all the way.

I will torque down the drain bolt, but I am concerned it might be something else, since the top of the differential is wet. Will top it off with gear fluid, that should tell me how much I lost.

Suggestions?

Thank you.

 

[Rand]

could be a couple things. if the vent is blocked it will spew somewhere.

a pic would be nice or exactly where its wet.

top of front top of back? by the pinion seal?

 

[Ursae_Majoris]

Back and the sides. Seems the only dry place was the front, where the fill bolt is. Could not see where the vent is. Isuzu extended all the breather lines (rear differential vent was ABOVE the spare tire), so I will need to jack the car up to check the vent. Rubber breather line was wet though.

Does front differential spin, if car is in two-wheel drive mode? Since moving out of AK, I have used 4WD once. Wonder how much fluid heats up in 2WD...
I will try to get a pic, but almost lost half of my face underneath the Axiom. Not much room to move around till it is on the stands.

 

[INDYMAC]

My first thought would be someone decided to help you out by overfilling.

My second thought would be to check the washer and drain plug for proper torque. Do you know what the torque is supposed to be?

Remember to always take the fill plug out before the drain plug!

 

[Ursae_Majoris]

I have Axiom FSM, so I can find torque values.
Overfilling is a possibility, but it was serviced last May....
I guess I won't know till I crawl under it this weekend. Need to buy more diff grease and brake cleaner before I do that.

Pulled out the cardboard this morning, and there was only one grease spot from the last night, so it leaked in the first three hours after I came home, then stopped. I take it as a good sign.

 

[MolaKule]

I had the same problem in a different vehicle. Pinion and axle seals ok.

Drain plug ok.

It was the gasket that seals the two halves of the clamshell.

 

[JTK]

Originally Posted By: Ursae_Majoris
Does front differential spin, if car is in two-wheel drive mode?


Yes.

The front right axle is live right up to the differential all the time, so differential internals are in motion any time the vehicle is rolling.

The front left axle is connected/disconnected by the electronic shift on the fly actuator that's mounted on the axle tube on the left side. Basically it slides a splined collar on/off to connect that side solid to the diff when 4x4 is commanded.

I owned a 2002 Isuzu Rodeo, but don't recall all the details. I don't believe these front diffs had a removable front cover. The whole carrier has to be removed out the back. It's possible that gasket is leaking.

The shift on the fly actuator also holds a small amount of gear oil. That could be leaking too.

These SOTF actuators notoriously will corrode internally and lock-up if you don't exercise them every few weeks. You definitely need to cycle the 4x4 on/off as you roll out your driveway more often.

Keep in mind the leak could be coming from the engine and dripping down.

Joel