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Old 01-19-2021, 05:22 PM   #1
rechinca
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Help reading rear ended gears

So like everything else on this truck, it’s challenging. Pulled the diff cover, ugly and filthy, to clean, seal and refill. Thought it try and check the rear end for gear ratio. This is how they are stamped. Teeth cut right through the stamping! By rotating it looks to be a 3.08. Any thoughts?
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Old 01-19-2021, 05:40 PM   #2
Boog
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Re: Help reading rear ended gears

There are numbers stamped some where in there. Can you see the end of the pinion gear? Should be something like 17/43 if I remember right stamped on one of them.
Geezer will know.
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Old 01-19-2021, 05:40 PM   #3
pjmoreland
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Re: Help reading rear ended gears

1*:43 is probably 14:43, which would be 3.07. If you want to know for sure, then you could count the teeth on the two gears.

Last edited by pjmoreland; 01-19-2021 at 06:11 PM.
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Old 01-19-2021, 09:11 PM   #4
rechinca
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Re: Help reading rear end gears

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Originally Posted by pjmoreland View Post
1*:43 is probably 14:43, which would be 3.07. If you want to know for sure, then you could count the teeth on the two gears.
That’s about what I figured based on marking the driveshaft and rotating the tires two full turns (no posi). Came to just past 3 full turns, but not 3 1/4, so in the 3.07/3.08 range. I needed to get the cover sealed back up and filled to move it tonight so, no more looking right now. As filthy as this was, I am going to run it a couple of months and then drain and refill again.
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Old 01-20-2021, 12:38 PM   #5
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Re: Help reading rear ended gears

If there stock gears look at the code on the RH axle tube. Mine is a 1972. Code RHA which is a 3.07
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Old 01-20-2021, 06:15 PM   #6
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Re: Help reading rear ended gears

Kind of off the subject but did they make 3:07 and 3:08 rears at the same time?

I like the teeth counting idea if necessary.
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Old 01-20-2021, 06:44 PM   #7
Andy4639
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Thumbs up Re: Help reading rear ended gears

Turning the wheels and watching the drive shaft is about as close as you need. It will be dang near perfect for figuring out your gears. If it only turns 3 times you know it's not a 4:11 set!

If it turns 4 times you know it's not a 3:08 set. So with that being said if you turn it 3 1/8 times then it's got to be a 3:08.

3.07 gears were installed in automatic trucks. 3.73 gears were common in three speed trucks, and 4.11's were found with granny geared four-speed trucks.

This isn't gospel seeing how my 71 has 4:11 gears and it had just a normal 3 speed in it when I bought it from the original owner. But it's the only gear sets they used back then for the common truck.
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It sucks not being able to hear!

LWB trucks rule, if you don't think so measure your SWB!
After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.
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Old 01-20-2021, 09:01 PM   #8
BRL
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Re: Help reading rear ended gears

Quote:
Originally Posted by Andy4639 View Post
...3.07 gears were installed in automatic trucks...
That would explain it.

I got my rear end from a green '70 longbed with an auto column shift in the salvage yard, and the numbers on the ring gear divided up into 3:07.

I just thought it was a 3:08 for some reason all this time.

Thanks!
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Old 01-20-2021, 10:54 PM   #9
Andy4639
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Talking Re: Help reading rear ended gears

Quote:
Originally Posted by BRL View Post
That would explain it.

I got my rear end from a green '70 longbed with an auto column shift in the salvage yard, and the numbers on the ring gear divided up into 3:07.

I just thought it was a 3:08 for some reason all this time.

Thanks!


I want to know can you tell any difference now that you know!
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1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver
Seeing the USA in a 71


Upstate SC GM Truck Club
2013,14 and 2016 Hot Rod Pour Tour


http://upstategmtrucks.com/



Get out and drive the truck this summer and have some fun!
It sucks not being able to hear!

LWB trucks rule, if you don't think so measure your SWB!
After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.
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Old 01-20-2021, 11:19 PM   #10
rechinca
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Re: Help reading rear ended gears

Quote:
Originally Posted by BigBird05 View Post
If there stock gears look at the code on the RH axle tube. Mine is a 1972. Code RHA which is a 3.07
Unfortunately this axle came out of leaf spring truck and when they installed it, they appear to have ground off the stamping. It was done pretty decent as a retrofit, but unfortunately no way to tell by that. This truck had some bad mechanic work previous to me, so it’s one fun adventure after another.
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Old 01-21-2021, 02:12 AM   #11
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Re: Help reading rear ended gears

Quote:
Originally Posted by Andy4639 View Post
...

I want to know can you tell any difference now that you know!
Of course I can, my "seat-of-the-pants" gauge is telling me it's more torky overall by .01% or something.

...what'd they do, add or subtract a tooth someplace?
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