gear option?

[292farmer]

i went past a speed trap and it flashed my speed and surprisingly matched my speedo, but that means my truck doesnt have 4.56 gears(i thought the speedo was off to age..so figured 4.56 was my gears) when i redid the math i got gears around 5.13 was that a gear option in a dana 60 axle behind a 292 and sm465? my dad believes that was possible, just wanted this boards input thanks! thought u guys might like some pics of the truck being put to work for the landlord right after i found the speed trap. the trailer wasnt heavy what u dont see is the bed of bricks, cinder stones and paving blocks.

[CE20934]

The 5.14 was available with the Eaton, so I don't see why it wouldn't be available with the Dana.

[Jacfourteen]

Yeah the dana's came with the 5.13's too. Man I thought my 4.56's were low, I couldn't imagine any lower. That thing must scream down the Highway!

[1969 GMC]

I have never heard of a 67-72 with a dana 60 and oem 5.13 gears, I thought the reason they even used the D60 was the 4.11 as highest ratio in the eaton. But stranger things have happened, I guess. If you ever take it apart to regear, you can probably recoup some cash selling the gears if they aren't roached.

[292farmer]

thanks for the replies i have yet to try hwy as 45mph is screaming, (got it to 50mph in neutral down hill lol) i dont plan on getting rid of the gears i plan on keeping this truck stock, and i dont need to go fast, if i need to go fast i take the wifes car or the baja bug.

and i apologize for not getting back to u all sooner as i was busy working and building a tool rack for my truck.

[292farmer]

i am planning on draining the fluid out of the axle tomm and putting new in and i plan on pulling the diff cover to solve the ratio once and for all, as i figured maybe weight/friction of the truck and the road and the speed trap and speedometer both being slightly off may make 4.56 seem like 5.13..does dana stamp the gear ratios on their rings? does any one know how much fluid i should buy? thanks!

[capev86]

you need an overdrive with like a .5 ratio. keep the 5.13 and get a 6 speed manual with a .7 5th and .52 6th. in top gear you'd be cruising like a 3.73 geared truck with a 700-r4. i would have gone this route on my 72 burb w/ 4.57 rear but i have a 3 on the column (not on the floor) and want to keep it that way. i'll soon be doing the 4.10 3rd member swap and hope to add the borg warner od to the saginaw some day. the 4.57 is just too darn low even around town with a 307 under the hood. i'm wanting another gear by 35mph. a 4.10 is only a 10% improvement over the 4.57 so it won't be a noticeable change from a stop, but the faster the road speed, the greater the savings in rpms.

[Jacfourteen]

I'm planning on doing a t-56 swap eventually that way I have the best of both worlds good low end and top speed.

You might get lucky my rear still had the tag on the cover that said "D60 4.56" and another tag that said "use limited slip diff oil only". It's probably a good idea to change the fluid anyway. Some have the ratio stamped on the ring gear and some have the # of teeth of the gears (example 45-11 means 4.10). just get the numbers and you will be able to figure it out, or someone on here can for you.

Edit: I looked around and if it's a 5.13 the ring should have 41 teeth and the pinion should have 8 teeth.

[292farmer]

okay thanks! hopefully they have a diff cover gasket in stock so i can do this tomm. thanks for the teeth count!

[Jacfourteen]

Originally Posted by 292farmer

okay thanks! hopefully they have a diff cover gasket in stock so i can do this tomm. thanks for the teeth count!

If they don't have the gasket just clean it with brake or carb cleaner and use some black or blue permatex RTV silicone, bolt it down, then let it set up according to the directions before adding oil and it will be fine. Oh, and don't clean the excess untill it dries, then you just cut it off with a razor knife.

[292farmer]

i was afraid the gasket would tear, so figured i'd be safe, might do that anyways if they dont have it in stock.

[292farmer]

so pulled diff cover off and saw these numbers on the ring gear
12-6-71 dana 30360 j1d33x 4110
i didnt have a jack(mia) so wasnt able to rotate the gears to see if their were any other numbers,
im guessing 1st num date of manufacture? after dana part number and then id number whats last number? their are no dashs in any these numbers. thanks! if don't answer back soon its because, my wife is doing her online courses and has taken the computer.
thanks again.

[Jacfourteen]

I could be wrong but the last numbers seem to denote 41 ring teeth, 10 pinion teeth, AKA 4.10 ratio. How did you do your math? did you guestimate rpm or do you have a tach? Oh and you could have just pulled the truck forward or back to see the rest of the ring, that little of rotation with no lube won't hurt anything.

[292farmer]

the speedo was cop verified and the tach is brand new and i pulled it apart and checked wires to make sure it was hooked up right. i had speedo verified while running at 2000rpm and my speedo said 35. cops said 36, so pretty close i figure 1-2off either way. the thing with it being 4.10 is that means im supposed to be doing 44-45mph at 2000rpms 4.56 says 40-41mph 5.13 says 35-36mph.
i did think that the 4110 might be the ratio. but it cant be as that means ive been driving ten over the limit and w/ open headers. my math is as follows (rpms)(60)/(gear ratio)(tire rev. per mile)
tires are 235/85r16 looked it up says 650rev. per mile so... 2000x60/5.13x650
im in 4th gear which has a 1:1 so that means the rear end gear stay the same right? if it was 1.5 it would be 1.5x5.13 instead right?
i didnt roll it around as i was on an incline and it was raining and moving the truck would put me into mud...i did shine a LED up in their looked like their were 8 gears on pinion, maybe 9 looked like the pinion came in just below the rings centerline, so im guessing i looked at right part lol. sorry this was so long...

[indiandog]

check this web sitehttp://vexer.com/automotive-tools/speed-rpm-calculator it says 5.13

[69GMCLonghorn]

Yeah, with those tires and a 4.10 rear end, you'd be taching around 2800 RPM... AT 70 MPH!!!