Small leak

I have a slight leak at the front differential and drive shaft. It is nothing major and I don’t even notice a oil slick under the truck when it sits for a longer period of time.

Thanks for sharing.

Let us know when the front differential goes.

Hi Furbous94,

What year? Is it a Chevy Tahoe? What mileage?

Typically, a front or rear diff. seal leak that is very slow leaking is very minor. That “area” of the car sees lots of road trash, and if you used the 4WD at all in mud or sand, it can eventually begin to wear the sealing surface of the input to the differential. Unless it is seriously leaking, check the level of the front diff and ensure it is full. Make sure the fluid is clean. Make sure you use the right fluid (usually SYN). Make sure the “vent” to the front diff. is functioning.

Also, if you DON’T use the 4WD very much, find a nice, clean, non-paved area and engage it for a 1/4 mile or so at least every six months. It helps the entire system remain functional and helps the lubricants distribute and normalize at operating temp. (NEVER ENGAGE IT ON PAVEMENT!)


Can I just drain the fluid, pull the drive shaft and then change the seal?


Sure, if you have a seal driver, impact gun, seal alignment tool, and you’re sure the yolk isn’t worn with a groove in it. But why would you do any of that for a small leak? The chance that you’ll damage the alloy casting is much greater. BTW: you never mentioned miles, and never confirmed type-- that’s helpful. Otherwise, good luck-- you’ll need it.


1999 Chevy Tahoe 2 door 4WD 5.7L 158,000 miles

What does a replacement differential cost?

Why look for a new diff at this early stage? You crazy or rich or both? LOL sorry had to ask. Diff leaks are as common as A-holes. If it is leaking, rather than just seeping then it is not critical. If you let the diff leak its fluid out it will quickly degrade the gear surfaces and then need replacement. I would pull the shaft and replace the seal going into the diff…I believe the diff you mention doe have a removeable cover? If so pull that also and re-do the silicon gasket maker that has probably dried up and shrunk down to a point at it is causing a leak. YOu are at the early stages of a leak, so just fix it with a new seal, and gasket maker before you look into a VERY costly diff swap.

It is Your pinion seal I assume that is leaking. You might get some more miles by replacing the pinion seal only but it is an indicator you need a $1200 dollar or so work on the bearings in the front transfer case.