Differential fluid level?

[Happy Jack]

I have a 88 Bronco II with a C-5 and a T&M Doubler. I have a low pinion full width 9" axle in the rear and we cut the sping pads off and installed new ones for the BII width and proper driveshaft angle. Someone I know sugested to relocate the fill plug as the pinion gear and bearing is now higher than the fill plug for oiling. I plan to drive this on a 1000 mile road trip in April and was looking for info on how to determine the proper fluid level and fill plug location. Thinking about just comming off the existing fill plug and extending it higher.

I did a search but did not find anything. I can provide pics if needed.

Sorry, If this should be in the off-road projects section. I didn't scroll down far enough.

 

[Verno]

Not sure easiest way to modify, but your fluid level should be just above the pinion shaft when level. If you tilt the diff rearward (raise pinion up) the you will need more fluids to compensate for this.
If you're not fully assembled you could turn it level (parallel to ground) fill to proper level then turn up and mount. Use a coffee stir stick or narrow straw to slide down hole to find what fluid level is at this angle; compare to pinion angle and add as necessary. Wouldn't want to drill new hole with diff installed and fluid in!

 

[Happy Jack]

Thanks for the reply. It's been installed for a few years but has a week engine. It has been used for short in town trips and as a trailer queen during that time. I have a new engine to go in it for the trip in April.

On the 9" the fill hole is in the 3rd member. So I can just project a mark forward on the front of the pinion support using the ribs on the 3rd member as a guide. Then screw a peice of pipe in the fill hole and install a 90 degree elbow on the end and set the level using measurements from the floor to the mark on the front of the pinion support.

Will the seals in the axle tubes hold to keep the extra fluid out of my rear brakes though?

Heard that some rearend folks require the use of a climbing gear oil with the high pinion 9". The fill hole is rotated a bit higher already just not as high as the pinion. And the ring gear should pick up oil and bring it up and forward just not sure how much. Just wondering the best way to go about this. If there is one.

Thanks again for the info.

 

[BK_89iX]

The other day I saw a youtube video of a 8.8 rear end running with a clear composite cover. Check it out. The oil seems to get sloshed around by the ring gear VERY well during operation. I mention this solely FWIW - not saying you don't need a different fill level in your case.

BK

http://www.youtube.com/watch?v=BZ1Y_goOb-g