The Stovebolt Site Forums The Shop Area Engine Shop 1949 chevy 2ton rear axle came out......yikes

hey there.today while driving my 1949 chevy 6400 with 2 speed rear end, i came up to and intersection right in front of my work.i had it in neutral while waiting for the light and when i put it in gear to go, the driveshaft just spun.i thought that the 2 speed had shifted into neutral on its own being that it is not hooked up.after getting it home after work being pulled by another truck, i noticed that my right rear wheel/hub were halfway off.i took the wheels off and removed the axle to find my bearing was completely torn up.i lost sunlight and will continue on it tomorrow.my guess is that the 2 jam nuts inside loosened a little bit so the axle slid out enough so i couldnt drive, and towing it home probably tore up the bearing.

does anyone have any other guesses? has anyone experienced this? hopefully i can just go get a new bearing and be on the road for the 4th.

Thanks, Danny

Sounds like a likely chain of events.

Check the splines on the end of the axle shaft and hope that the splines in the side gear are also OK.
Biggest concern may be the bearing seats and surfaces on the spindle, if they are not damaged you should be just fine replacing bearings and a new lock/tab washer. Probably need a new seal too.

Grigg

i checked the splines last night and they looked fine.it wasnt too bright out, so ill have another look today.just hope that all that needs replacing is just a bearing and a seal and a new jam nut lock tab washer.I will return after further investigation.
Thanks,
Danny

I think you have 2 unrelated problems. The spline are long enough so that the locking nuts can't come loose enough for the spline to pull out of the side gear. You will need to check the axle spindle to see if the bearing spun. It probably did. You will need to dimple the journals and dress them down to where the bearing fits correctly or you will have bearings spinning from now on. As far as the axle being in between gears, I would check the shifting mechanism. I am assuming you have vacuum. Either your spring that holds it in low is broken or you don't have enough vacuum to pull it into high. Hopefully thats all it is. Spider gears brake occasionally, and that is major.

where is the axle spindle? Does it have anything to do with the pinion gear and bearing, because i just had that apart and replaced that seal.hopefully its not that.So far today i have the hub off and the part that the hub bearings ride on are in good condition.the only damage ive found so far is my outer bearing is destroyed.Im goig to put the axle back in without the hub and see if i can turn it.I guess that will tell me if i have a inside gear problem??as for my vacuum to change from high to low, its not hooked up.could it be that its just inbetween high and low and i need to get back in gear? More investigating....

Thanks, Dan

The spindles on the rear axle are the ends of the axle tubes/housing that the wheel bearings fit on. Just like the front axle spindle is where the front wheel bearings (and hub) slip on.

Grigg

The bearings are housed inside the hub.How do i press them on the spindle?What do you mean dimple the journals?

Dan

The bearings are a slip fit on the spindle.
They are supposed to stay in the hub, although the cone of the outer will fall out once you remove the spindle nuts, and the cone of the inner will come out after the seal is removed. Both races/cups will need to be pressed or driven out of the hub.

By dimple the journals he was referring to the practice of repeatedly dimpling an undersized journal with a hammer and a center punch, then dressing it to size best you can.
I really don't like this "repair" technique and urge you not to use it. It is not a long lasting and reliable solution, but it is quick, cheap, and easy..

Grigg

If your bearings have spun, you have to do something. On modern equipment I would simply replace the housing because I have dozens of them laying around. On old stuff that is obsolete, its a different story. You may find a used one, but its not that easy. Or you can remove the housing, weld up the journal and turn it if you can find someone with a lathe big enough to swing it. Or you can hire these guys. http://www.axlesurgeons.com/ However, they are not cheap. Back in the 50's and 60's we used to dimple the wheel ends and run them another 100,000 miles with no problem. I doubt that your truck will ever see that kind of miles any more.

On the two speed rear end, is it a spring that just holds it in low and vacuum holds it in high? Or does the spring hold it in high and low, and the vacuum just switches it from one to another.How does it get into neutral if that is what happened to me.

Thanks,
Dan

The spring holds it in low range. Vacuum holds it in high range. There is no actual neutral. However if it jumps out of one range and there is nothing to pull it into the range it will be between ranges which actually is like a neutral. It sort of ratchets into low when you give it gas and sort of ratchets into high range when you let off the gas.

so if my vacuum is not hooked up, what is it doing now.is it just stuck in between gears till i hook it up?

If your vacuum is not hooked up, the spring should pull it into low range. Look for a broken or missing spring.

if one of the rear wheels is up in the air, tranny in nuetral spin the wheel and see what the drive shaft does.

do i pull off the mechanism part of the vacuum on the rear end to see if that spring is broken or missing?

Danny

Do you have a shop manual?
In times like these one will be a great asset.

Grigg

no i do not.I will have to invest in one.
Danny

I have another small issue related with this.on my rear hub, the outer bearing that im replacing and the race that is in that hub, is it pressed in? I cant seem to get it out.I would just leave the old race in there but i got a new tapered bearing and it has a different race.Not the barrel bearing kind.Just wondering if the outer race is pressed in.There was a locking ring in a groove right up against it, and i gout that out.I just cant seem to get the race out.Has anyone experienced this?

Danny

The spring is a coil spring wrapped around the shaft under the vacuum chamber. The coil pushes the axle into low range. Vacuum overcomes the spring and pulls it into high range. I am assuming you have one hub off and that side on a jack stand. Try moving the shift lever which is on the drivers side down low facing the front of the truck. Move the lever down as far as it will go. Stick the axle into the housing until it is splined up. Turn the drive shaft with the transmission in neutral and see if the axle is now turning. The GMC maintenance manual does not address the subject very well. It assumes the user to have a general knowledge of 2 speeds. I can take a picture of a vacuum 2 speed and post it. That might help you figure out if you have parts missing. The cup is pressed into the hub, but it does not require a hydraulic press. I have a 3 prong tool to install and remove cups, but it can be done with a long punch. If you look from the brake drum side of the hub, you will see a small part of the cup protruding out. Tap it there on one side and another and it will come out. You should use a punch with a good square edge so it doesn't slip off. It will take a pretty good sized hammer. Do the reverse to reinstall the new cup. Be very careful not to slip off and scratch the bearing surface. You will be able to feel and hear when the cup has bottomed out.

Doesnt the cup come out towards the inner bearing?Is that what your saying? Do i have to remove the inner cup as well or will it clear it.Ive removed the inner bearing and seal.I just want to get the outer cup out.

As for the vacuum, mi vacuum lines are not hooked up.So i dont think moving that lever in side the cab will make much difference.
I am going to take the vacuum shifter out tomorrow and have a look inside.

Danny

The outer bearing race goes outward, you drive it out from the opposite side. In your case, lay the drum outside down and you should be able to see the lip from inside the bore. You may have to wipe out all the excess grease & grime to see it tho.

The outer cup drives out away from the brake drum. The lever I am referring to is on the third member, next to the pinion bearing down low facing the front of the truck. That is where the spring is that holds it into low range.

Im not sure as to how that race/cup goess outward.How does it clear that gear on the outside of the hub?

Danny

Do you have the hub off the vehicle? If so, there wouldn't be a gear in the hub any more. Is the gear attached to the axle shaft. If not, you probably have a broken axle shaft which explains why the rear appears to be in neutral and has nothing to do with the 2 speed. A photo of what kind of mess you have sure would help.

Wel tonight i finally got everything back together and fixed.Turns out, nothing was wrong with the two speed.I got a new outer bearing, put it all back in, put the hub back on, axle in and it turns the drive shaft again.Somethin weird was going on earlier.I got it back on the road around 11:30 pm and its ready to cruise for the 4th of july.Thanks to all who helped in this post.I couldnt have done it with out you guys.

Danny