Rear Gears for 1950 3600 3/4 ton

Howdy guys, Ive been reading alot about changing the low gears in the rear end of my truck. Ive got a 235 with a Four on the floor. Im assuming the rear ratio is 4:57 to 1 and Ive read about a 3:90 for these 3/4 tons and I may have found a site. http://www.heavychevy.com/html/rearend.html They have a rear ring and pinion 3:90 for 3/4 and 1 tons but the year for them is 62-72 trucks. Ive heard that these are interchangable or at least the 67-72 years were. What is everyones suggestion or comments? Thanks guys.

 

They should just change out with what you have, all the way to 78'?
You could call Hoopers Rear End in Sun Valley, Ca. and ask Tony or Dave about the year and what will work. I had them build me a 342/1 and it is Great. And I fly down the road at highways speeds. Go to some recking yard and find an old catering one ton and take its rear end out.
Good luck.

 

Thanks for the reply. Do you have a 3/4 ton truck as well? What about this ring and pinion classicparts sells?

http://www.classicparts.com/1947-54-Rear-End-Gears/productinfo/93-511/

This is the 3:55:1 ratio but they dont specify it for 1/2 ton or anything for that matter. Do you think by chance I could bolt this in to my rear?

 

Mine is a 1 ton, but both the 3800 and the 3600 use the same housing, Because our trucks are narrower I had the housing shortened to fit the wheel base by Hooper's Rear End Exchange Inc at 12201 Branford St, Sun Valley, CA 91352 ask for Tony or Dave.
However now there is selling wider fenders (fiberglass?) and the stock younger truck rear-ends should bolt up and with the use of the wider fenders no one should know. I think the host sell the 1/2 ton parts.
The heavychevy parts guys just sell up to year 72, there should be a rear end place somewhere near you where you could go and discuss the newer ones up to 78 that will work for you and see if you can get somewhere around a 342/1, with the 235 and a single barrel that is about all you need. If yo go lower in the gears you are going to need more carbs, or a bigger engine.

 

Thanks again for some info. How did the new gears help your speed and RPM? I talked to a machinist I know and he said it wouldnt help with putting taller gears in the rear because my 4 speed tranny is geared so low. He said only thing I could do is get a new tranny and new rear end. What does everyone think ?

 

No matter how many speeds a trans has: 2 (PG), 3, or 4, the top gear is always 1:1. Just the 1st, 2nd, or 3rd will vary in ratio but once in top gear they are all the same. Any trans that is not 1:1 in the top gear is an overdrive trans such as the Borgwarner, the crappy T5 and the very good Tremec TKO. If you want to keep a standard trans then the 3 speed with the Borgwarner OD is cheap, takes a fair amount of abuse, and gives a final drive ratio of 3.20 to 1 when used with a 4.57 rear end. It does require going to an all open driveshaft but maybe not for long. I am working on a 50 3/4T right now where I am trying to mount a custom built housing containing the BW OD unit in the hanger that is where the torque tube couples to the open rear shaft. If all goes well then the granny 4sp can be retained. We made a mid-driveshaft OD unit for a Hudson Hornet years ago that worked well and Hone-O-Matic did the same years later. I think Gear Venders bought out H-O-M and still offer a driveshaft OD but it is quite pricey.

 

And don't forget, if you'd like to keep your stock tranny and keep the original 6 lug pattern, then you might think about taking that big old rear axle out altogether and putting in a Colorado rear end. Same width, 3.73 ratio... Just a matter of setting the pinion angle and welding on new perches. While you're at it, you could add the part that moves the axle back to where it is centered in the wheel well. See Robert's pictures of his build. (He goes by mobileortho.)
I have a 3/4, and this is what I'll be doing. I priced a 2008 Colorado rear~ $400.00 complete. To me, that sounds like a pretty darn good price for a rear that has only 36,000 miles. A lot less to deal with to get what I'm looking for.
However you go, good luck!

 

Do you have a open shaft, and do you have 8 lug rims?

As Evan stated the 4th gear is 1/1 and the highway speeds are what they are, I believe Ron has seen me out on the interstate traveling with the traffic.

When I had the 514/1 rear end it was about 40/50 miles an hour unless I was freewheeling down a grade, when I changed to the 410/1 it was about 60 miles an hour and then the 342/1 was put in and I can travel at or above most unsafe highway speeds for that truck and it's front hacks. Going up steep grades I sometimes have to down shift once. With loads and a trailer on it I down shift on grades, but then again so does my F250 5.8cu .

 

Pumpkin Up Grade

The deal is : you need to find a 1 ton , like a G30 van or ex Postal van , like that as they're automatic eqipped and those are the ones with the 3.72 pumpkins , it bolts into your 3600 axle housing and is the easist thing to do .

Your 235 will have NO problems oushng it to 75 MPH on the flat .

I see you're in Colorado so look hard at dead ice cream trucks etc. as they're out there no matter what the nay sayers all claim .

It's like 454 V-8's ~ Pick-A-Part is crushing them for scrap as NO ONE wants them , the Hot Rodders down at the shop all whine they can't find them " anwhere " when I see plenty with 60,000 original miles being scrapped every day .

The tranny isn't the issue in getting your old truck up to highway speed ~ now you know the Machinist doesn't know what he's talking about , beware .

 

Guys Thank you so much for your valuable info. Love it. My truck is 8 lug wheels but how can I tell if it is open driveshaft? Nate, so if i find a 1 ton G30 Van pumpkin it will bolt right into my existing? A couple more questions, after I get the pumpkin in would it be wise to get a new brake system for the rear? and will I need a new speedometer gear in the tranny? Im gonna go take some pictures for yall in awhile here. Thank you so much

 

Okay guys, My truck is open driveshaft. Nate I found a rear pumpkin from a 95 1 ton G30 Van today. Guy says I can come and remove it. Any information about installation? Here are some pictures I took earlier of the rear end. Sorry not the greatest pics, hope you can tell!

Edit: Guess the 95 G30 is too new, didnt have the right pumpkin

 

Destry~ Seeing the u-joint means it's open. The 1/2 ton trucks come stock with a closed drive shaft called a torque tube. These 1/2 ton trucks have a harder time converting to a newer rear end than we do. You can take your big, heavy, rear axle completely out by undoing the u-joint and undoing the shackle bolts. Disconnect the brake lines and then pull the whole back axle out. Once this is done, you can stick in a 5 lug rear end from a bunch of choices, (some with disc brakes) or you have some 6 lug opptions that would allow you to keep a more stock, 6 lug look.
To me, swapping the pumpkin exceeded my desire. I'd rather get a much newer, possibly disc brake back end and skip the fun of a pumpkin swap.
You DO have plenty of opptions. Have fun with it!
Good luck!

 

Matching It Up

Yiou really do need to find that old van parked in a field of cowpies then scrootch underneath it and count how many bolts hold the pumpkin into the banjo housing , it that looks good , dismount it and them count the # of splines on the inner ends of the axle shafts before you pay for it .

Or , you can drive to a competent & honest rear end shop (kinda lets out Hooper's in Sun Valley) and they'll do it for you , with a gaurantee and everything , I have no idea how much Lolly ($) they'll ask tho .

 

I like the idea of finding one of those older g30 van pumpkins. I was back home in Kansas City for awhile but now im back in the mountains and I spent alittle bit of time searching but couldnt find anything. I looked for a rear shop in KC but didn't find one, maybe i didnt look hard enough! My search continues. Nate do you see those g30 vans alot? EDIT: Also Thank you everyone for your highly valued input!

 

Yes , BUT !

I allready have a yard full of junk I bought because someone promised they'd buy it if only I found it... .

I don't chase nor sell parts anynmore .

Whenever I hit the road in America, I see these old things rusting away in driveways and back yards , every state in America and then I hear " but I can't FIND one !~ " on these forums . you've gotta go beat the bushes , that's all .

 

Sorry Nate, I wasnt asking you or trying to ask you to find anything for me, so would I be looking for a G30 van between the years of 67-72?

 

Yes , But ~

No worries , I was just getting that out there in advance .

You want one with an automatic tranny , this is why old Campers and Postal vans are so good ~ they're always properly equipped .

Ice cream trucks tend to be made from old , gutted Campers or Postal Vans then rund straight into the ground , the rear end doesn't much care unless you abuse it and that's hard to do with a wheezy old V-8 so don't let the brushed paintjob and gaping rust holes, dents and mouse poop scare you away .

 

haha thanks, i went on a wild goose chase with my gpa this last weekend because I got happy that i found a G30 van, so we drove about 54 miles to Odessa, MO got all our tools together and hopped under this 1 ton and noticed immediately it was not the right housing! yikes, i shouldve guessed for a 1995 G30, but i crawled through the tall grass and had a good time anyway.

 

The price was not all that bad and they fix anything, just have to watch that dam cat. They will answer most all your Q's about the rear end.

 

FWIW- I have the same truck- '50 3600 with original drive line-

My primary goals were:

1. improved brakes front and rear, since I also wanted

2. increased highway speed if needed

and lastly

3. matching 6 lug wheels on all 4 corners ( I went with 15" to keep costs down)

I got a 3.42 rear axle from an S-10 4x4 (width fits better than a 4x2) with newer drum brakes (disc brakes are available but the local yard only had one with drums), then found a 1/2 ton (happened to be a '53) front axle for the front. I then put a disc brake kit on the front and a new master cylinder with booster- I still have the original transmission in place.

I couldn't be happier with this set up. Truck drives 65-70 if need be, brakes are great- my wife will now drive it- she wouldn't before due to "holding everybody else up" at 45 mph, and distrust of the old brakes. It made a world of difference and the truck still looks pretty much stock. I did loose a bit of height due to the wheel/tire size I chose- it just wasn't worth the extra expense for taller wheels and tires to me. I'm sure there are many other ways to accomplish this, but this is what worked for me and was pretty easy and inexpensive to accomplish. We've driven "Ernest" more this year than the previous 4 years we've had him due to these changes.

The only snafu was I ended up having to get different wheel offsets for the front and rear since the axle widths are a little bit different. I may have been ok with leaving them the same but I wanted the front and rear tires to fit the same in the fender. No big deal, but you may could find a rear that fits a little closer.

If you get a "new" half ton axle, go ahead and replace the king pins while it's out- It'd be a little easier access.