Rear axle leak

I have a leak coming from a few spots on my rear axle. This is on a 90 lwb montero with a 3.0 and a/t.

One leak is at the pinion and I believe was from a bad U joint/vibration breaking the seal.

The other leak appears to be from the small off center hole in the axle shaft as pictured here


I was hoping someone with experience taking the rear axle apart could shed light on the leak coming from that hole. I am hoping to remove the rear end and change some bearings and seals when the weather warms up and I can use my bike to commute or I get time off from work.

Is your rear end vent plugged ...?

The rear 'axle bearings' on a Mitzu axle shafts are packed grease as a front wheel bearing would be ... Rear axles meet at a block in the diff/lsd...Rear axle shafts are shimed ... You have a seal at the end of the axle housing to keep the 90w oil out of the greased axle bearing ... And said seal is DOA ...



Have fun

Captain Gear Box

Hazardous Toys inc

No, the vent is clear.
I tried to remove the axle shaft on the side that leaks when I changed my pinion seal last time. I don't know if you remember but you had suggested I use a chain next time to pull the axle. Still haven't done it yet.
Both the inner and outer seals go in the tube from the axle sides?

Thank you

No theres a inner seal at the end of the axle housing ..That keeps the 90w oil in the diff ... That's bad replace the inner seal ... The axle shaft is made to piss 90w out that hole if the seals dies ... The outter axle seal you would have to replace as in press off the axle bearing to get to the out axle seal ... Replace the inner seals ... Clean and repack the axle bearings and run it ... The outter seals don't go bad ... Check your axle 'end play' before you remove the axles ...

Thanks for the info. Your help and the FSM gave me a better understanding. I have a feeling the bearing will need to be changed as well. Its been leaking for a few weeks now. Probably took the grease out and cooked it. Its recently had a slight vibration/noise over 55 I was hoping it was new tires or the shop not balancing them correctly. Going to rotate the tires to see if it changes anything in the mean time.
Will need to get some more tools together for measuring end play and pulling race/seal out of the tube before I tackle the job. Think I can make something like whats used in the FSM out of steel to get the bearing and shaft apart.

No and no .........And no ...

Mitzu rearends dont die ..... They can .......But thats rare..Bad axle bears make noise 'all the way down to a stop.." ... Now driveshafts make noises at 55mph.. Is the rear driveshaft 'out of time' ...? .. Some years ago I chocked <img src="/forums/images/graemlins/frown.gif" alt="" />..Hit a rock in my Rally Truck and plucked the right rear tire off the truck ...As in we have three wheels on the truck ..One off in the weeds ..LOL.. Bent the rearend housing the spring and u-bolds ... Reused the axle shaft .. The axle has been pissing out the axle hole for years ... Its still going .. Installed two new seals repacked the axle bearing ... Its still pissing out the hole ..LOL ... Someday <img src="/forums/images/graemlins/rolleyes.gif" alt="" />.. I will install the new axle shaft I have .. Or not .. You got years on that axle bearing ... Grease or 90w gear oil its fine as long as it has some sort of lube .. 'End play' its a "feel" not a tool measurment.."Going to make a tool for axle bearing replacement" ... Good luck ..I have OEM Mitzu and Toyota and so on tools ...They dont work on AZ trucks ... Your in NYC rust .. Buy a oxy acetylene torch and a HF 20 ton press thats how the pros do it ...

Hope I'm not coming across as rude ...Not trying too..

Captain Gear Box

Hazardous Toys inc

I'll rotate the drive shaft 180 degrees and see if its better.
I appreciate you sharing your experienced knowledge <img src="/forums/images/graemlins/kewl.gif" alt="" />

Agree with HazT, check your driveshaft "carefully" for any nicks or dents.

John B.

Thanks for listening .. I'm a 'mechanic' to pay the rent ... So to most people I'm a thief and don't know what hell I'm taking about ... <img src="/forums/images/graemlins/rolleyes.gif" alt="" />..High JB..

Axle' bearings and 'diff' bearing make noise all the time .....Untill.............................They get loose enough that the 'ring-n-pinion' looses its 'setup' then you get a 'whine' at 40 to 70 ...Or.... As in my ALS Raider the factory spec sucks on rearend gears and my rearend has allways been set up 'off' from new and whines some ... But you can turn said whine on and off with on and off of the gas peddle ...Driveshafts vibrate at 50 to 60 you can feel it in you butt in the seat ..

Is the drive shaft bent.?... Lost a weight.?..Look for a 'spot weld' where the drive shaft spit a weight...Did you lift your truck and the u-joint angles' is all dicked up....?

Rear end and stick-shift trans work is a 'feel'...Big chunks if OEM FSM is FOS..

Pull the drive shaft and wheels and brake drums and 'grope' the rearend and 'feel' what you can 'see'... Take a good size hammer and give each axle shaft a good whack on the end.. Then feel the 'axle end play'...

Is this Greek ......?

Have a good day

Captain Gearbox

Hazardous Toys inc

I did 180 the drive shaft to the pinion flange and the vibration is less.
Saw two weights on the shaft but and did not see clean spots. I'll look again to make sure nothing else fell off. Its not bent or dented.
Seems to me that after driving 15 mins or so I get more noise and slight vibration.
I do have a whine like you mentioned that comes and goes depending on throttle position. Most noticeable at 1/16-1/8 throttle when going 55-60. I'm at stock height as far as lifts.
Will take the wheels off and disco drive shaft to fumble with it properly when I can.
Have a car front end to rebuild this weekend for a relative (free) struts, calipers, hoses, control arms and ball joints. As long as it goes smoothly I should get to mine.

Maybe I'm wrong about the throttle. It may be more like a sweet spot when your coasting not accel or decel on flat road and noise/vibration goes away for a second.

Is this a old noise or new noise..?

Yes GEN1 Monty rearends are more aft to be set up 'off' then 'right'.. (My right..Not Mother Mitzu right.. Thats 0.03 but thats a mile in a half in my would ..) ..It sounds like the gear set is off.. But its not off far enough to kill a gear set ... Just it makes a little noise and the only people on the planet who here it is me and you ..

Whats a "over night" oil sample say .??

I need to add this to my last post .. You can not check (feel) a rearend with the wheels or drums/disks or driveshaft on the rearend ..fact...AND ,,,,,,, Testing a rearend on 'jackstands' get you no where..fact ..

Not sure exactly how long its been making noise and I've only had it on the road for 5 months. Have had holes in the muffler that was changed not long ago and bad U joint. I changed the leaking pinion seal in January. Attempted to remove the carrier but failed to get the first axle shaft out during that time. Been more paranoid about it since. The leak was noticed not long after on the side I tried pulling. Still have not at least checked end play. Seems to make more vibration going through slight corners maintaining highway speed turning one way not the other. Sorry I can't help you help me more.