The Stovebolt Site Forums The Parking Lot '60-'66 Trucks I messed up my rear end...

So my son and I are just about done doing the brakes and wheel bearings on our '66 C10. We put the axle back in, and I was showing him how you spin it a few times to make sure its free etc...Only I forgot to put the pin back in that connects the two small gears in the rear end (sorry for the lack of technical terms!). Sure enough, a couple rotations of the axle, and the two little gears popped out onto the garage floor. I tried rotating them back in, with no luck, I can get one, but not both.

So what do I have to do here? Do I need to pull the whole rear end out and put it back together or is there a trick to get it squared away without pulling it?

Second question: I have 4.77 gears in there now...The neighbor has a '70 C10 rear end with 3.73? gears that he will give me/sell to me cheap. I would rather run those. Can I pull the gears out of that housing and bolt them into mine? I don't want to change the whole housing, just the rear end gears etc...

I have not looked at the manual yet because I lost the CD somehow. Note to self...I do NOT like electronic versions of manuals..Gotta get a "real" one!

Thanks!

Erik

You should be able to roll them right back in. Put one in & hold it while you turn the carrier over enough to put the other one opposite it. Then roll the carrier till the hole for the pin lines up with both gears. If both don't line up remove one & move it one tooth over. Start the pin through one gear till you get the C washers on & the axles pushed out. Push the pin rest of the way in & put in the lock bolt. The later models had thrust washers behind them but I don't think that model did. The earlier models had a block between the axles but I don't think that one did.

I see what you mean...I was trying to do them both at the same time. I'll try it that way tonite....

Thanks

Erik

Are you sure they are 4.77s? 4.10 was as deep as was available factory.

I was remembering wrong...4.11 was what I got with my math,probably 4.10s then. Either way, I still want to swap them out eventually.

Thanks for your advice, I got it squared away tonite, its all back together. What a relief!

Thanks

It should swap. Your best bet would be to swap the entire carrier rather than just the r&p. That will keep them matched up.

Erik, Changing over a set of gears can be very frustrating & time consuming, especially if you have never done one before. If you have another complete rear end and you know it's good, I would swap over the whole thing.
There is also a way that you can change the gear set without setting up the ring & pinion . I wont guarantee it, but you might get lucky. I have done this before & it worked fine. take the entire carrier out with the ring gear & shims along with the pinion gear, shims & crush collar, & install them in your original rear end exactly the way they were in the 70 rear end.The shims need to go back in the same way they were.
You should be okay as long as the housings are the same, I'm assuming they are both 12 bolts. Also install a new pinion seal.

Or you can just use just the ring & pinion gears but they would have to be properly set up with new shims & crush collar.
A good rearend guy could do this for you if you havent done this before.

When you say you would swap over the whole thing, do you mean the whole housing, wheel to wheel, or do you mean unbolting the guts and swapping them into my '66s housing as one big part? I don't intend to take all the gears apart if I can help it, but I was under the impression that I could just remove all the gears in the "pumpkin" as a unit. Does that make sense?

Yes, the entire rearend will swap, with only a few alterations. IIRC, the '67-'72 does not have the panhard bar bracket that the earlier rear has. i think I saw somewhare that the lower shock mounts were slightly different, too (don't hold me to that). But otherwise, they are the same.

The whole thing would be the entire rear end, drum to drum. Bolt it in & you're done.
What you are trying to do is what I just explained above. It will work but you have to put the carrier shims and the pinion shims back in exactly the way they all came out of the 70 rear end.
And you also have to use the pinion gear that goes with it. They are a matched set & have to be used together . The ring gear with the pinion gear from the 70 rear is what makes up the 3.73 ratio.
Also before you get too far ahead, count the teeth on the ring gear and also the pinion & divide them. The total will be your gear ratio. I would count them on both rear ends, that way you will know exactly what you have when you start.

Im assuming both rear ends are from 2wd 1/2 ton trucks with coil springs?

There is an article in the new issue of Classic Trucks magazine about this very subject . Might be worthy of checking out !

Easiest swap is definitely one entire housing and all its guts for another. I just did that exact thing with a 69 rear end into my 64.

As I understand it, the 12 bolt got a little wider from axle flange to axle flange in 1970, but not by much, only an inch or two, which some people consider a better look under the wheel wells anyway. Panhard bar mount should be the same 65-72, just confirm both rear ends are coil spring as previously stated.

Thats right, Jeff. Thanks, I see what you mean with teh first post now...

Thanks...I will go over and have a look at it this weekend. He was a little...inebriated...when he was trying to rememebr the specifics of his parts...

Hey I'm looking for suggestions for my 61. The rear end in it now is the original, it's 3:90, vibrates pretty good at 80 to 100 kilometers an hour, so I obviously need to do some work to it or replace it. I was considering replacing the guts to a taller gear ratio, but after reading this post it almost sounds like changing the whole axle is easier...is it also cheaper? What rear end will fit in a 61 half ton? My truck is 6 lug, so it would have to be a 6 lug rear end. Looking for taller gears, I want it to cruise on the highway fairly easily. Tried to figure out an RPM calculator without much luck...tranny is a granny low four speed, engine's a 283, and the tires are 235/75R15's

i put a 77 chev rear end into my 63 gmc just a little math and some welding worked great

wouldnt a 77 rear end be 5 lug?

On 2wd they are 5 lug, but 4x4s still used 6 lug.
On the vibration, are you sure it's in the rearend? Could very easily be a U-joint, carrier bearing, loose wheel, or misbalanced wheel/tire assembly.

Hey Bill, when I bought the truck, it vibrated like heck for the 5 hour drive home...previous owner said it was the driveshaft, he was right mostly...I had that replaced, turned out the old one was once a two piece , but someone cut out the middle joint and welded the two halves together, they didn't do it quite straight. It still vibrates but not near as bad. The shop that replaced my driveshaft also replaced the u-joints, and said that the rear end needs work. The yoke that connects to the driveshaft from the rear end (sorry for the lack of technical terms) feels loose if I grab it and shake it. Maybe it's a worn bushing or bearing? The wheels were recently replaced, it does this with the old set and with the new.

Sounds like a the pinion bearings.

is that an easy fix? Does it involve removing the gears?

I can't offer much regarding the 61, I'm only just familiarizing myself with the 63 and later gm truck 12 bolt, but I can say that for the 12 bolt job you do need to pull the carrier, then the pinion out of the housing to get to the pinion bearing, if memory of the shop manual serves correctly. So yeah, gears gotta come out, full-on deconstruction of that rear end.

I'm rebuilding the original from my 64 now, and I've got everything stripped out of the housing with the exception of that pinion, and I plan to tackle it this weekend. Normally you'd need a press to get the bearing off the pinion gear, but I can't say if that's always the case with a shot pinion bearing. Mine's shot so I'll let ya know.

Yours may well be shot too, that wonky driveshaft prolly did a number on it. When mine went, the pinion gear slid out and ground into the carrier, basically leaving the rear in need of a full overhaul. So I took the quickest, cheapest route and swapped in a 69 12 bolt I found on craigslist for $75. For the 61, you may be looking at some custom fab-work to get your trac bar right and all that, but a full rear end swap is prolly your friendliest option.

As a side note, I'll try to keep track of everything I'm doing with my 64 12 bolt build-up and work it into another thread or a tech article for everyone.

Paul

I had low MPG with the factory rear end mated with my V-6, on my truck and decided to change from the Dana 44 3.92 down to a 3.23 gear. I contacted Precision Gear and ordered a Pinion Gear, Ring Gear and new barings for the kit. The kit comes with ALL the shim rimgs you'll need. You will need a GOOD mic to measure the thickness of the shim rings so you don't waste time putting in a shim that's too thick or to thin.

While we had everything apart we took time to clean out the axle tube, you'll be surprised just how much rust and debris will come out. Just ball up some rags and push them through with a broom handle do this several times, like swabbing out a cannon barrel. Use a light to see if you have it all cleaned out. Unless the wheel barings are new, spend $10 more bucks and change those to.

It was an easy change out, BUT you do need a special dial flex mic to get the alignment set just right. When I did mine a mechanic friend helped me and we took a lot of pictures.

Here is the album, hope this helps you.

http://rides.webshots.com/album/570438270cjSEvE