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-   -   MOnte carlo 79 rear end? (http://www.hotrodders.com/forum/monte-carlo-79-rear-end-128244.html)

rockabilly66 11-15-2007 07:03 AM

MOnte carlo 79 rear end?
 
hi
Where can I find info of my montecarlo 79 reaer end, It's a v6 231 T top.
thanks

schnitz 11-15-2007 08:48 AM

What exactly do you want to know? Gear ratio? How to upgrade to rear disc brakes? How to repair/rebuild it? How to swap to steeper gears? We'll need some details of what you want before we can help.


In a while, Chet.

schnitz 11-15-2007 09:00 AM

Just did a quick search to possibly help in what you're looking for. Try here , here, or here.


Maybe you'll find what you are looking for in one of those links to existing threads on this forum. Hope it helps.


In a while, Chet.

rockabilly66 11-16-2007 07:25 AM

Hi
 
I need to know the gear ratio
thanks

schnitz 11-16-2007 10:44 AM

Quote:

Okay, guys - I know this has to have been answered a million times, but I can't find it here anywhere right now. I'm trying to determine my 8" Ford ratio. With both wheels off the ground, I turn the axle and get 1.33 turns of the axle for each full turn of the u-joint! Now, I've heard of economy gears, but that's ridiculous.

I was told to take the rear end cover off and mark a tooth both on the rack and pinion gears with something (piece of tape or scratch with awl). and count the number of teeth for both of the gears.

re: Figuring rear axle ratio
It's a characteristic of non-posi rears. The wheel on the other side was probably turning the other way. They don't always turn the same amount as the one you have your hand on, either, so make sure it's immobile before you count. Then turn the tire TWO full turns while you count the drive shaft revolutions.

The above was copy-pasted from assorted postings from the first link I gave.

The following is not a 100% foolproof method, and will not get an "exact" numeric figure, but will get you very close. Basically, what you need to do is as follows. I plotted this out so I can make it easy for anyone to duplicate.

1. Park the car on a flat, level surface. Block the front and back of each of your front tires, and do the same to one of the rear tires.

2. Raise the unblocked side of the rear end (axle) of your car and firmly and securely supported on a jack stand. Never leave it supported on just the floor jack, that is very unsafe, and can result in serious injury or even death.

3. Put the car it neutral (engine off).

4. Mark the universal joint at one of the 4 bolts that hold the caps to the rear end. You can use a small piece of masking tape and place it over one of the 4 bolt heads.

5. Rotate the tire until you get the mark on the bolt cap to an easily identified and repeatable location on the rear end center section (the "pumpkin" in the middle of the axle). You can mark the pumpkin if you want to. The important thing to remember is to have a repeatable mark to stop on for easy reference.

6. Place a mark on the raised tire, running from the rim to the tread surface, running straight up at the 12:00 position. I use a helper (my "helper" is my wife) for the next step. It helps to have an extra set of eyes, but this can be done alone, just take your time and go slowly.

7. Spin the drive shaft two full rotations and count the number of times the marking on the tire spins.

If the tire spins roughly 2 and 3/4 revolutions, you will have a 2.73 axle ratio. Three and almost a half revolutions will give you a 3.42 rear ratio, and a spun tire of 3 and 3/4 revolutions will give you an approximate ratio of 3.73. By the same way, a 4.11 ratio would have the tire spin just over 4 times around to two times around by the marking on the bolt cap on the universal joint.

My '78 Monte Carlo had a factory ratio of 2.29 (about 2 and a third of a tire rotation).

Hopefully I didn't make this as clear as mud, and it helps you out.



In a while, Chet.

DHMag 11-16-2007 11:54 PM

quickest way is to check the code on the axle tube. or pull the diff cover off and read the pinion gear, it will have tooth counts on it for both the ring and pinion. ex: 41 ring gear teeth/17 pinion gear teeth = 2.41 ratio

schnitz 11-17-2007 02:11 PM

Quote:

Originally Posted by DHMag
quickest way is to check the code on the axle tube. or pull the diff cover off and read the pinion gear, it will have tooth counts on it for both the ring and pinion. ex: 41 ring gear teeth/17 pinion gear teeth = 2.41 ratio


Not if you live in the salt /rust belt LOL! :thumbup: I've only once been able to find the axle code on anything that old (or older and sometimes even newer) that was just covered in rust. But, I do like the idea of pulling the cover and counting the number of teeth. That also gives you an excuse to change the differential's gear lube.



In a while, Chet.

jimfulco 11-22-2007 12:08 AM

Quote:

Originally Posted by schnitz

7. Spin the drive shaft two full rotations and count the number of times the marking on the tire spins.

That's backwards. Two turns of the tire, and count driveshaft revs. You don't really need two people. I just position the valve stem at the 6:00 position, and I can feel it when it's back at 6:00 the second time.

schnitz 11-22-2007 09:08 AM

Quote:

Originally Posted by jimfulco
That's backwards. Two turns of the tire, and count driveshaft revs. You don't really need two people. I just position the valve stem at the 6:00 position, and I can feel it when it's back at 6:00 the second time.


Oops. I type corrected. :thumbup: Thanks Jim.


In a while, Chet.


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