Nate T.

It's probably a dry rotted spot in the line near the pump.

I've never seen an electrical schematic for the Mule, but if you have one please post it. Me and a couple guys here in the avionics shop will look it over

Better to have the drum stripped out than the axle or the rear end.

The 550? Dang I saw one on Amazon for $15. If anything just use the housing and swap old parts in.

Fuel pump also. Its vacuum operated so if the pump diaphragm is ruptured it can literally suck fuel into the crankcase. The good news is there are some really inexpensive fuel pump replacements available.

It's easy to pass fuel through the carb if the needle valve is worn and not making a good seal.

Plus your weight and any passengers plus fuel.

Knowing how unscrupulous warranty people are, they'll probably say you overloaded the payload capacity which caused deflection in the axle.

That kind of damage is the result of misalignment and/or corrosion issues from poor QC and defective parts. If the alignment was off, from a bad bearing or improper assembly the gear would "waller" in there enough to wear down the teeth. You would have to put a small block Chevy in your SxS and do burnouts every day for a year to grind those teeth the way they are if everything else was correct.

Isn't there a transaxle or transmission bolted up to the motor? Could have a bad seal that is leaking fluid through.

Hey no one is forcing him to work there, let him do what he wants. We had a coupling like that gear at work strip out and looked exactly like your rear end there. Except it was 60 years old with daily, 24hr usage.

The back plate of the hub brake drum will interfere also if its bent out of alignment. I had to adjust mine after some repairs with a mallet.

The gas caps have little silicone flapper disks in them that vent one-way. When they start to deteriorate they get really sticky and ambient pressures aren't enough to break the seal. The pressure you're sensing when opening the cap may be air rushing into the gas tank.

I would suspect the gas cap not venting and creating a vacuum. Seen it, fixed it. Crack the gas cap loose and try idling then.

OEM lights and not LEDs, correct? If that's the case those OEM lights draw a lot of current, probably in the neighborhood of 50w each. The stator on an old Mule isn't that beefy to begin with, so you will get a significant voltage drop when the lights are on. Maybe you don't really have an issue. Or maybe you have a slight short to ground somewhere in the wiring with rubbed through wire insulation.