Hello everyone, I am from Iquique Chile and I have a 1981 Blazer k5 that I am repairing. I would like to know if any of you can give me information about the ratio of the pinion and the mountain gear, with which I originally bought it, this truck only It has had this owner and unfortunately I pumped the crown and my mechanic could not save it, and I lost the ratio, can someone give me that information? , it will be 3.77, ? 4.11? or different? Thank you very much in advance
CK5
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Ned information pinion and ring
- Thread starter bojank5
- Start date
Welcome @bojank5 certainly glad to have members from around the world.
If you divide the teeth on the crown( we call it a ring) gear by the number of teeth on the pinion
This will give the ratio of the axle gears
Example 41/10=4.1 ratio.
If you asking about what ratios to change to for climbing the exceptionally steep mountains we can help you figure that out.
Need to know what size tire you want to run, transmission model, and engine.
If you divide the teeth on the crown( we call it a ring) gear by the number of teeth on the pinion
This will give the ratio of the axle gears
Example 41/10=4.1 ratio.
If you asking about what ratios to change to for climbing the exceptionally steep mountains we can help you figure that out.
Need to know what size tire you want to run, transmission model, and engine.
hello !!! Thanks for answering, the truth is not for climbing, it's more for highways and deserts, not dunes, rather roads in poor condition, the wheels are 33x12.5 r15 and I have a 5.7 V8 engine, in second gear, with my old sprocket I could reach 100 km/h and only used third gear on the highway almost as a fourth gear
Assuming this is a 4x4 (because most Blazers are) and you only lost 1 differential, you can just determine the ratio of the other differential. You can rotate the driveshaft and count wheel revolutions or look at the numbers stamped on the edge of the ring gear. 62MPH in 2nd gear sounds like some pretty tall gears, so maybe now is the time to go to something like a 4.10 or 4.56 ratio, for much improved acceleration and holding of O/D once it drops in. It just means you'll buy 2 sets of gears instead of 1.
This is also where people here normally chime in with the advice not to put gears in the 10-bolt rear, but upgrade to something stronger.
Seriously, the search function here is your friend.
This is also where people here normally chime in with the advice not to put gears in the 10-bolt rear, but upgrade to something stronger.
Seriously, the search function here is your friend.
Do you have a 4 speed? that was an option for 81 k5. Doing some math with guessing th350 second gear of 1.52 at 2400 rpm with 32.5 diameter tires, the closest gear (sprocket) ratio is 2.56 to 1. I am making a lot guesses, but the ratio was an option for 81 k5 with 4 speed automatic.
Which axle are repairing the front or rear ?
How many speeds is the trans ?
Which axle are repairing the front or rear ?
How many speeds is the trans ?
I was looking at the brochure for 81. I miss read the option table. Yeah I didn't think the 700R4 was available in 81. Nor god forbid the 2004R.
Wow - it does look like this truck has a pretty tall gear ratio.
Agreed on 1982 as the intro year for the 700R4 but as said anything could have been swapped out over the years.
Back in the late eighties a good buddy of mine first truck was an early 81 ( build date 10 of 80 ) model year K/10 with a 305/TH350 combo and the almighty 2.56’s - his first mod was a 4” lift and 35’s and it could not pull steam off of a hot biscuit. The size of the pinion head on those 2.56’s was impressive!
By the end of the following year my buddy went a little overboard and had solved the lack of power issue by installing a good ole set of CUCV D60/14B axles along with a fresh 454 - lack of power issue was solved…
Agreed on 1982 as the intro year for the 700R4 but as said anything could have been swapped out over the years.
Back in the late eighties a good buddy of mine first truck was an early 81 ( build date 10 of 80 ) model year K/10 with a 305/TH350 combo and the almighty 2.56’s - his first mod was a 4” lift and 35’s and it could not pull steam off of a hot biscuit. The size of the pinion head on those 2.56’s was impressive!
By the end of the following year my buddy went a little overboard and had solved the lack of power issue by installing a good ole set of CUCV D60/14B axles along with a fresh 454 - lack of power issue was solved…
Welcome.
Fotos de tu Blazer?
Fotos de tu Blazer?
I didn't even know you could get 2.56 gears in the trucks. That's got to be super slow on stock tires and terrible on 33's. If it really is an overdrive transmission, the ratio could go up by 2 whole points for a 78% increase in torque. Yee-hah!
Here in Iquique the roads are long and the roads are accessible desert and not rocky, here more speed is needed and less torque I still haven't checked my truck's pinion and crown (since I changed it a long time ago and I don't remember and it's in the paint shop) my wheels are 33 x 12.5 R 15 and I do not intend to change them it is a mechanical truck with L -1-2-3-R and 4H and 4L gears and I think I need the 4.11 ratio for both transmissions
4.11’s work good with 33” tires. Sounds like you have a 465 manual transmission, which will do fine with that gearing and tire size.
At 65mph the engine should be at 2700rpm with 4.11 gears and 33” tires. It’s a little on the high side but will keep the engine well in its torque curve.
At 65mph the engine should be at 2700rpm with 4.11 gears and 33” tires. It’s a little on the high side but will keep the engine well in its torque curve.
4.1 would be perfect, 100kmh all day long in 3rd, or high gear.
Great looking K5. Looking forward to mas Foto.
Great looking K5. Looking forward to mas Foto.
