massimo 500 four wheel drive issue

[Sgriger534]

I have a MSU 500 and sometimes it acts sluggish in 4x4 and you can smell hot gear oil. 

I'm Thinking it is something binding up the the transfer case or front differential but before I dig into it I wanted to see if anybody had a similar problem.

 

Thanks, 

[kenfain]

When you decide to go in, don't forget to post pictures, as well as updates. Good luck!

[Travis]

25 minutes ago, kenfain said:

When you decide to go in, don't forget to post pictures, as well as updates. Good luck!

And pictures are worth more than 1,000 words when it comes to putting it back together, never say "I'll remember where it goes", i learned the hard way on some things.

[cliffyk]

There is no transfer case per se, thetransmission output is routed to a short lateral shaft parallel to the crankshaft . That shaft sports a beveled  pinion on the inboard end that drives a ring gear on what is variously called a "middle drive gear shaft" or "output shaft" that runs fore & aft in the crankcase.  This shaft drives the front differential and rear final drive--it is powered when the centrifugal clutch on the crankshaft  locks up (I.e. in both 2WD and 4WD), it is lubricated by the engine oil..

There is quite little in the front differential to "bind"--when was the gear oil last changed? First thing I'd do would be to drain the diff fluid and see what it looks like (metal particles, sludge, etc.) and give it a good sniff to "see" if it smells burnt.

 

MSU500 - Middle Drive Gear shaft:

MSU500 - Front Differential: