72 c20 rearend gears
 

Does any one know what gears were in these? How can i tell what rear end is in it? Its rpms are way up there at highway speeds. Does any one make a more highway friendly ratio that will work? Thanks for any help.

Ron

Re: 72 c20 rearend gears
 

Can you perhaps post a picture of the axle? Then we can id it for you.
(if it's a perfect round one it most probably is a Eaton and has 4.11 gears)
I have the same high rpm's on the highway :)

Cya,
Edmond
Dutch Longhorn
:metal:

Re: 72 c20 rearend gears
 

If it has a big round pumpkin...drain plug in the back...on training arms and full floater...more than likely if orginal it is at eaton ho52...there were four sets of gears for them I could ever find were used...4.11...4.56...I got that one...5.13 and 3.90 which seemed to be aftermarket gear no longer made...and impossible to find...I have spent many hours looking and searching...My truck runs at 3100 rpm at 55...u may have any one of these gear ratios...and they all scream...I'm going to put a dana in mine...there is a kit to make them attach to the trailing arms for about 150 dollars...I don't know what your situation is but If u need info unfortunely I know more than I wanted...I'll give some web sites...chart with tire size and ratios...and the best place to talk to I found was randy's ring and pinion...Hope this helps:banghead: http://www.ecklerstrucks.com/product...ED8N6AG42WBWA9
http://www.ringpinion.com
http://www.drivetrain.com/rearend.html
Don't be affraid to call Randy's they really will help...very good buissness
keep in touch

Re: 72 c20 rearend gears
 

one other thing jack the truck up and pull the cover and the ratio is on the gear...or take someone and have them spin the rear wheel one revolution and count how many revolutions the driveshaft turns...if it is five 5.13...if it is a little over 4 4.11...a little under 4 3.90...then call Me I want that rear end lol...if half way between 4 and 5 4.56...its not rocket science but it works...lol

why I am going with a dana is I can get any gear I want...pricy change over though...Tire height will help...yes bigger is better lol...but if your like Me u don't want the truck scrapping the moon lol

Re: 72 c20 rearend gears
 

First you need to know what you have. Check the rear cover. 10 bolts holding the cover on means the HO52, 12 bolts is the Dana. You can get better gears for both. The 10 bolt carrier has to be replaced with a carrier from a 14 bolt, but you have to swap the axle shafts, because of the splines. Or so I have read.

Re: 72 c20 rearend gears
 

Check this out guys - they have the 3.90 and 4.10 ratios !!!

http://www.oldchevytrucks.biz/catalog3/0044.html

Re: 72 c20 rearend gears
 

That's awesome! Thanks for the link!


Anybody try a Gear Vendors gear doublers on a manual 4-speed?


What's the possibility of finding a two-speed rear-end? Did 1 tons have those or only the bigger trucks?

Re: 72 c20 rearend gears
 

good luck at that link...they need to update it...I ordered 3.90 from them 2 months ago and never got em and they didn't even email me back...when I called two weeks later the said the discontinued them...sorry green machine...but if that changed please let me know...call them and ask if they got them in stock...good advice freddy T if its a ten bolt probibly ho52

Re: 72 c20 rearend gears
 

Carter hasn't had those gears since Art Houser died over a year ago. He was the maker.

Re: 72 c20 rearend gears
 

Crap - Sorry guys, I had no idea the catalog page was not current :( :( :(

Maybe this thought will be useful - a few years ago I went yarding hoping to replace a 4.56 with atleast a 4.10. The rear fill plug on the HO52 is large enough that if you remove it and use one of those little led flashlights and hold your mouth just right and turn the gears, it IS possible to read the tooth count stamped on the ring gear. That way you can determine the ratio without pulling the cover off of everything.

Re: 72 c20 rearend gears
 

FYI..the dana 60 has a 10 bolt cover. It is of irregular in shape.http://purplecranium.com/images/cat/...1061102777.jpg
If you have the eaton HO52/72 it will have a round cover that everyone calls a "salad bowl" shape.

The gear ratio you have in any rearend will depend on which engine your truck came with and what it was intended to do. With a small block V8 engine it is real common to have a 4.10 ratio with some having 4.56 grears. If the truck was intended to pull even larger loads you would get a ratio in the 5's or even 6's.

In the Dana 60 you can easily find 3.54's which would really lower your RPM's.

Where in Minnesota do you hail from?

Re: 72 c20 rearend gears
 

da burb exactly salad bowl eaton...question did any dana 60 come in 67 to 72 3/4 ton...trailing arms?

Re: 72 c20 rearend gears
 

i have a 71 longhorn 1 ton. it has the big round differential. it came with a big block and heavy duty everything. That means it is an eaton right? and what gear ratio does it probably have? I always thought they were like 4.11s cause up until a little while back i didnt know they even had 4.56's. now i know they go into the 5's. so im thinking it probably has the 5.13. with the mild 350 in it now at 55 it probably gets 8 mpg and the motor is turnin pretty darn fast. any comments are appreciated.

Re: 72 c20 rearend gears
 

yeah, engine and transmission seem to be the key here, my I6 got the 4.56 (not sure if you could even order the 250 with 4.10's).
I think manual trans V8's were more prone to get 4.10's and automatics got the 4.56's.......but that might be backwards :crazy:

I like to be different, keep the eaton, if you have a manual trans, you can always hunt around for a 4 spd. over drive.....think they were called A833's???? should be a direct replacement on a 2wd.

Re: 72 c20 rearend gears
 

I not sure 67 custom camper 327 4 0n floor it came with a 5.13 no spin eaton...someone changed it to a 4.56 no spin...round round salad bowl ten bolt eaton...My truck was a special order though so u maybe your right about your statement

Re: 72 c20 rearend gears
 

barepaint, yes, there are dana 60's out there with coil spring setups. Up until recently I have only owned coil sprung D60's.

Re: 72 c20 rearend gears
 

There was a post a while ago from someone who found there no-spin in a coil spring rear.......I didn't know eaton's were even offered in coil springs.

As for my previous statement.....that was really what 'basic stock' was.....back in the 60's and 70's it seems like you could order a car/truck anyway you wanted, my statement was just a GM generalization.

Re: 72 c20 rearend gears
 

yea the only thing i dont like about the low gears is the fact that you burn so much gas... but without them i doubt that big heavy c30 longhorn with a mild 350 would squeak the tires much less keep the 1 legger burnin all through 1st gear and half through 2nd.

Re: 72 c20 rearend gears
 

yes eatons were main stays in coils 67 to 72 3/4 ton eight bolt rims

Re: 72 c20 rearend gears
 

have a 67 c10 with drop out diff, with 4.56 want to go taller but was told no one has them ?

Re: 72 c20 rearend gears
 

A C10 with an HO52? not likely. Maybe an HO33 or 35, but they were discontinued in the early 60s. Could be an early pontiac rear. Further ID needed or a pic or 2

Re: 72 c20 rearend gears
 

Larger than a one ton. They usually have a 6xx gear and a 5xx gear set in them for the fast gears. The tires that came under these trucks are much taller so ratios are even lower.