Gear Ratio ???

[C-10 simplex]

Originally Posted by gregg72340

Not to even remotly try to hijack this thread but where do the early 350 diesels play into this? Would the basic small block application apply here? I just picked up a free 12 bolt from a diesel but havent had the time to check the ratio yet and would definitly like to get rid of my 2.73's

1) i did not read carefully---you are referring to the oldsmoboggie diesel, not the 6.2?
You got, get this----2.76 standard code HC2, 3.08 would be code HE3, and if 3.40 then code HE4, not sure if posi also comes with HE4 These are very strange ratios.

i'm not sure if these are dependent on GVWR's and the early diesel trucks had a crapload of them.

Would it be out of the question to take the cover off and physically count the teeth? The oil could probably use a changing anyways.

Originally Posted by LONGHAIR

I doubt that you will get much "fun" out of a 2.50 first gear with a heavy pick-up truck? You really need a lower rear end gear to make it more drivable, but that creates highway RPM issues.
These "performance car" transmisions just don't have a wide enough gear spread for trucks as an "all around" daily driver. The generally taller tires of a truck make it worse.

2) To me just banging thru 3 gears is fun. But yes, if you wanted better acceleration then maybe 4.11 would be better but then mpg might suffer.

3) i can't make any further "recommendations" for rear end ratios (esp when coupled with 4sp) because i'm not really qualified to----i'm trying to figure out my own situation as well.

i do, however, feel that riding a 10sp bike can be very educational----general consensus is that a taller ratio would take less "energy" to turn, but this is often not the case.

[LONGHAIR]

Originally Posted by C-10 simplex

12) To me just banging thru 3 gears is fun. But yes, if you wanted better acceleration then maybe 4.11 would be better but then mpg might suffer.

I'm not saying that it isn't...when you are somewhere that you can drive somewhat aggressively. But try to drive it "gently" around a city cop or when trying to haul something?

Take a drive down the main street of a big city where you might have to stop at the traffic light on every block.....

[gregg72340]

Originally Posted by C-10 simplex

1) i did not read carefully---you are referring to the oldsmoboggie diesel, not the 6.2?
You got, get this----2.76 standard code HC2, 3.08 would be code HE3, and if 3.40 then code HE4, not sure if posi also comes with HE4 These are very strange ratios.

i'm not sure if these are dependent on GVWR's and the early diesel trucks had a crapload of them.

Would it be out of the question to take the cover off and physically count the teeth? The oil could probably use a changing anyways.




2) To me just banging thru 3 gears is fun. But yes, if you wanted better acceleration then maybe 4.11 would be better but then mpg might suffer.

3) i can't make any further "recommendations" for rear end ratios (esp when coupled with 4sp) because i'm not really qualified to----i'm trying to figure out my own situation as well.

i do, however, feel that riding a 10sp bike can be very educational----general consensus is that a taller ratio would take less "energy" to turn, but this is often not the case.

Yup its an Oldsmoboggle diesel mess, but hey it was free so its worth at least a look, Im gonna have to take the cover off it and see what it is in the spring, just was curious if there was some set gear for it, I just got it 3 weeks ago and its buried in 18 inches of snow right now so its more a curiosity than anything right now, but hey hopefully its at least better than the 2.67 in the truck now .....

[gregg72340]

Originally Posted by gregg72340

Yup its an Oldsmoboggle diesel mess, but hey it was free so its worth at least a look, Im gonna have to take the cover off it and see what it is in the spring, just was curious if there was some set gear for it, I just got it 3 weeks ago and its buried in 18 inches of snow right now so its more a curiosity than anything right now, but hey hopefully its at least better than the 2.67 in the truck now .....

Ok this doesnt sound right to me pulled it apart this weekend and counted all the teeth four times and it came out the same to 3.15...........am I missing something here? Has GM stamped on the ring gear so its original???????

What do I have?

[C-10 simplex]

Sorry it took so long to respond. i really don't know much about rear axles but i wish to learn.

So how many teeth are on the ring and how many are on the pinion?

Also, i'm thinking? (hoping) that the number may be stamped somewhere on the ring?

[gregg72340]

Originally Posted by C-10 simplex

Sorry it took so long to respond. i really don't know much about rear axles but i wish to learn.

So how many teeth are on the ring and how many are on the pinion?

Also, i'm thinking? (hoping) that the number may be stamped somewhere on the ring?

Its 41 and 13.............There is GM stamped on the ring gear and an 8 and 1 but that is it nothing else, im just stumped on this one

[chopped81step]

A 41 ring gear & 13 pinion = a 3.15