gear ratios?

[stizkidz]

I found 2 complete K20's in the local yard. I was told by the yard owner that I can choose whichever truck I want and they will cut out the axles for me and it will only be $350 for both. I really want to get the axles with the lowest ratio. Is there any way to get the ratios without pulling the cover? A code somewhere or a tag maybe?

Thanks.

 

[readymix]

There might be an RPO code tag in the glove box. Write down all the codes you see that start with "G" then post them up here.

 

[dremu]

Depending on year, there may be an options tag in the glove box, or on a inner front fender. Older ones will spell out the code -- GU8 -- along with the meaning -- 4.10 GEAR RATIO (as an example, could be wrong) ; newer ones will just list the code. BTW, they're "Regular Production Options", or "RPO's". Search on that and you'll find lots of online lists.


-- A

 

[dyeager535]

Just hope you don't get a set with mis-matched gears, people do this for various reasons, I'd never consider spending $350 without pulling the cover and inspecting them for wear (and ratio) anyways.

 

[R72K5]

and youll run into GQ1 standard ratio on the labels sometimes and then youre screwed and will have to pull diff covers

and rpo codes will only be accurate if axles are original anyways

you can never know if ratios or axles been swapped

good luck

 

[Silver84k5]

Spin the hub on one side of the axle so it makes a full revolution.. count how many times the Yoke makes a full revolution. then Multiply by two (to account for the spider gears turning the other side the opposite way)


Although you should pop the cover and see what it looks like in there as was previously stated.

 

[stizkidz]

Ok, update!
Went back to the yard today and I collected as many specs from the now 5 vehicles that I have to choose from.
Here is the first one that I will most likely get the axles from:
1- 1985 K20 3spd diesel, 130k miles, RPO sticker said 4.10 gears. It definitely has a Dana 44 up front and a 14bff in the rear. Both are 8 lug. The RPO stocker also mentioned that it had "heavy duty springs" and the truck, as it sat, had no bed on it.
2- About a 1980 Dodge Ram 2500 and it had both the front and rear in it. It had 8 lugs and the rear looked like a 14bff to me.
3- This truck had only a rear and it was a K30, probably 1980 era. It looked like a 14bff on steroids (it was even bigger). It had 8 lugs.
4/5- The last two were much older, probably between 74-80. Milegage unknown on both and both had caked on grease like crazy on both axles. One had a V8 and the other had an inline 6 and I have no idea about either gear ratio, as I could not find the RPO stickers. The rears in both were 14bff and the front appeared to be dana 44's (but from all the grease it was hard to tell). Both trucks had all axles with 8 lugs.

Basically, for $350, should I get the 1985 set of axles? Or do any of these other trucks sound like a better choice?

 

[fatbob]

I'm suprised an 85 would have a dana 44 and not a 10 bolt. And the 14bff is a gm axle so it would have to have been swapped into the the dodge. Anyway the 4.10 gears in the 85 sound good and if you intend on going to crossover steering later on, take another look at those old greasy dana44's. If they have flattop knuckles, see if you can get just the knuckles for cheap. Spare axle shafts would be nice too.

 

[stizkidz]

There is a chance that I made a mistake in ID'ing the front axle on the 85. It very well may be a 10 bolt and not a D44. My question is, even if it is a 10 bolt, should I buy it anyway since it already has the matching 4.10 ratio and 8 lug spindles? Is there a foolproof way of telling a D44 apart from a 10 bolt?

 

[k5floyd]

i think the 10 bolts will have "ears" on the bottom of the pumpkin. i know atleast all the rears do and my front 10 bolt has them.

 

[divorced]

You can tell a D44 because the cover is flat on the left and right, the 10 bolt cover is round.

 

[nomadman]

There is a chance that I made a mistake in ID'ing the front axle on the 85. It very well may be a 10 bolt and not a D44. My question is, even if it is a 10 bolt, should I buy it anyway since it already has the matching 4.10 ratio and 8 lug spindles? Is there a foolproof way of telling a D44 apart from a 10 bolt?

'divorced' is right about the D44 ID. Look for vertical flats on both sides of the cover. As far as the 10 bolt, correct me if I'm wrong, but you can't do a X over conversion to a 10 bolt. With a D44, even if the pass side knuckle isn't a flat top, it could always be swapped out later. I'm looking into the possibility of swapping my 10 bolt out for a D44 right now. Mine is a DD and gas $$ is bad enough so I don't want anything bigger/stronger than that (like a D60) and with the Eastcoast terrain, probably not necessary.

 

[metalbonde]

i pop in 2 questions here if ok..

in a 1977 C20 there would be a 14bff right?

the guy said it was 8-lug , whatabout gear ratio for this axle ? it but no rpo-codes , truck cab burnt down)

pleas say that 2:73 wasn't avaible , i already have that junk

 

[fatbob]

"nomadman " Flattop knuckles from a dana44 will fit a 10 bolt also.

"stizkidz " Go for it! 10bolts and dana44 are about equal strenght wise and spare axle shafts might be easier to find for the 10bolt.

 

[nomadman]

"nomadman " Flattop knuckles from a dana44 will fit a 10 bolt also.

"stizkidz " Go for it! 10bolts and dana44 are about equal strenght wise and spare axle shafts might be easier to find for the 10bolt.

That's GREAT info!! I know of a D44 w/ both sides having flattop knuckles for FREE! So are the spindles and rotors interchangable too? I already have 2 xtra 10 bolts for spare axles, although 1 is a 30 spline, running 28 right now.

 

[nomadman]

Fatbob, will 28 and 30 spline side gears interchange so i can run the bigger axles? The later model 10b w/ the 30 splines is 3:42's and I'm running 4:10's.