Joined: Dec 10, 2017 Posts: 337 Location: Southern Maryland
Posted: Mon Mar 05, 2018 12:59 pm Post subject: M38A1 Rear issues
So, Sunday I decided to fire the Jeep up and run it up and down the driveway for fun...remember I'm new at Jeeps!
It started right up, so I climbed in, put it in 2-wd 1st gear and let the clutch out...the entire jeep started shaking like an off balance washing machine but not moving. I then put it in 4-wd Low and let the clutch out and the Jeep started moving with no shaking...now I started thinking I didn't have the gears shifting right so I started playing some more...
Long story short the rear drive shaft turns, but the jeep doesn't move.
I know parts can be found, but they add up fast $$$.
Would I be better off looking for a used axle or are they all subject to the same issues and I should just rebuild what I have? I'm not ready to tear it open just yet to find the problem (no room in the shop til next week), but thought I'd ask if broken rears are a common issue?
Thanks,
Mike B _________________ Mike B
1953 M38A1 Brush Truck
1952 M38
1951 M100 Trailer
Joined: May 08, 2011 Posts: 98 Location: New England
Posted: Mon Mar 05, 2018 8:16 pm Post subject:
I know around me you can usually pick up used ones pretty cheap. It would still be a crab shoot. You might luck out or you might find yourself in the same dilemma. junk bearings... leaky old seals... 65 year old parts... =o/
Repair wouldn't be too bad if your doing it yourself. If you have to farm it out then it will be pricey. Not allot of people doing that work anymore as most people opt for a used replacement these days.
Allot of factors to consider. Open it up and see where your at and check locally if anything used is available near you.
Best regards ~ Matt _________________ Matt, Truck 1/4 Ton 4x4, M-38 (G-740)
Willy's Model: MC
DOD April 1952
Ser. # 63326
Joined: Feb 17, 2012 Posts: 530 Location: Del City, OK
Posted: Mon Mar 05, 2018 9:05 pm Post subject:
I had something similar - the front - come to find it was a broken spider gear, jamming up the differential... cost me $100 for a new set. Got them from AJP... you need to open it up to see what is... _________________ Hal, KB1ZQ
TSGT, USAF (Ret)
1952 M-38 CDN CAR 52-31313
1952 M-100 Strick #104
1951 Willys Wagon (For Sale)
1954 Willys M38A1 201001205
Tornado Alley
Del City, OK
Joined: Mar 22, 2017 Posts: 301 Location: Great Mills, MD
Posted: Mon Mar 05, 2018 10:34 pm Post subject:
Hi Mike,
Most likely a broken axle or broken spider gear(s). Broken axle will vibrate like you describe. Never drove with spider gears that went tits up......so not sure what that's like. Pop the cover and it should be painfully obvious what's wrong. Regardless, you'll need to flush metal debris and replace the oil......so open her up. Dana 44 parts are still readily available and not that expensive.
Joined: Dec 10, 2017 Posts: 337 Location: Southern Maryland
Posted: Mon Mar 05, 2018 11:05 pm Post subject:
I'll see if I can get it opened up in the next few days...
If it's a broken axle won't it just slide out drum/hub and all?
Wonder why it doesn't shake when in 4-wd? Never mind, I think I figured it out...when in 4-wd the rpm is limited to the slow speed of the truck rolling with the front axle engauged, not allowing the rear axle to spin free.
Thanks for the input!
Mike B _________________ Mike B
1953 M38A1 Brush Truck
1952 M38
1951 M100 Trailer
Don't pop anything! Just jack the rear axle off the floor. Spin one tire, if the other one doesn't rotate in the opposite direction you have a sheared axle shaft or a set of broken spider gears.
If you are a novice mechanic then take care to read the civilian jeep or spicer manuals very carefully before you start tearing drive axles apart. They can get an ignorant person in a real quandry real quick.
Joined: Mar 22, 2017 Posts: 301 Location: Great Mills, MD
Posted: Tue Mar 06, 2018 9:12 am Post subject:
Hi Guys,
Wes, I suggested pulling the cover because he said the driveshaft moves but the jeep doesn't. To me that would mean the issue is in the rear.....so he's pretty much already done what you wanted him to do by jacking it up and spinning a tire. The problem is in the rear, so he's going to have to open it up to fix it no matter what. Unless of course he just wants to junk the rear or bring it to someone else to fix. But hey......nothing else has that great smell of 50 year old 90W gear oil that stays in your pores for days and makes people look at you funny when they get a whif! Did anyone mention wearing rubber gloves is highly recommended?
Mike, the axle won't just slide out if broken because it's retained out by the shaft bearing behind the hub. It's not a "c" clip design where it can come out of the rear and pass you on the highway, like in my 12 bolt Chevy rear. Don't ask how I know that can happen........it wasn't a fun day.
Makes no difference. With the axle off the floor it is easy to determine which problem he has. Sheared axle will leave one wheel turning very free by itself and the other will have the drag of the spider gears. If the spider gears are bad then neither wheel will have the drag of the spider gears, however their resistance to rotation will be the same. Broken axles are usually outboard so no need to pull the cover til you determine if you have enough axle to pull it out of the pumpkin. Beats the $&% out of the gear oil puddle on the floor when you really don't need it. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Dec 10, 2017 Posts: 337 Location: Southern Maryland
Posted: Tue Mar 06, 2018 7:46 pm Post subject:
Ok, right , wrong or indifferent I pulled the cover today. Everything inside looked good, no broken parts and no metal in the gear lube.
Jacked the Jeep up and turned the passenger side tire by hand while laying on the floor looking at the gears. Tire spins with some resistance and the spider gears spin and look good. Then I noticed the drivers wheel wasn't turning so I reached over while still laying on the floor and that wheel turned real hard, so I got up and walked around to get in front of it to get it a spin. As soon as I grabed it I noticed it wobble up and down like it had a broken axle at the hub. I pulled the cotter pin and took the castle nut off by hand (knowing this was not a good sign). Once the nut was off I pulled the tire/wheel/hub off and discovered there was NO key in the slot! Who would take the key out and put it back together??? The out of balance washing machine action I felt was the axle wobbling in the hub.
I cleaned everything up, put the wheel/hub back on with a key in place. reinstalled the axle cover, refilled with 90 wt gear lube and took it for a quick ride up and down the driveway!
When I get to the actual restoration I'll replace the hub because the axle key slot scored it up pretty bad.
I'm glad that all it was...
Thanks for everyones input!
Mike B _________________ Mike B
1953 M38A1 Brush Truck
1952 M38
1951 M100 Trailer
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