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*C-10 simplex* · 12-30-2010, 05:39 PM

Ok, all awake now--i work 3rd shift/night shift unfortunately hence the need to sleep during the day.

Also, i'm sorry---i rushed thru my notes and didn't list properly all the info:

In addition to the eng/trans combo you also need to know your GVWR rating which is printed on the certification label which should be on the drivers door jam.

So, 2nd try, In 81:

If you have a 6 cyl and your GVWR is 4900 lbs., AND you're 2WD your std axle ratio GQ1 is 2.73 regardless of which trans you got----3sp, 4sp, or auto.

If you have a 6 cyl and your GVWR is 5200 lbs. AND you're 2WD, your std axle ratio GQ1 is still 2.73 regardless of which trans you got---3sp, 4 sp, or auto.

Everything same as above and your GVWR is 5600 lbs. you still got 2.73

Now if the GVWR is 6100 lbs. (6100 lbs. in a 6 cyl truck wow

) AND you got a 6 AND a 3spd then then std axle ratio GQ1 is 3.08 not 2.73

NOTE: i think it is because if this very reason is why GQ1 was never assigned a set number?

If the GVWR is 6100 lbs. and you got a 6cyl and you got a 4spd or auto, then the std axle ratio GQ1 is 2.73.

Now for 1/2 ton trucks with small block, not big block 8 cyls and 2WD:

If you have GVWR of 4900 AND a 3sp or 4sp, then GQ1=2.73
If you have GVWR of 4900 AND an automatic, then GQ1=2.56

If you have GVWR of 5200 AND a 3sp or 4sp, then GQ1=2.73
If you have GVWR of 5200 AND an automatic, then GQ1=2.56

5600lbs and 2bbl engine (check your vin#) and 3spd, then GQ1=3.08
5600lbs and 2bbl engine and automagic trans, then GQ1=2.73

5600 lbs and 4bbl engine and 3spd, then GQ1=3.08
5600 lbs and 4bbl engine and 4spd, then GQ1=2.73
5600 lbs and 4bbl engine and automagic, then GQ1=2.56

6100 lbs and 2bbl engine and 3sp, then GQ1=3.08
6100 lbs and 2bbl engine and automagic, then GQ1=2.73

6100 lbs and 4bbl engine and 3sp then GQ1=3.08
6100 lbs and 4bbl engine and 4sp then GQ1=2.73
6100 lbs and 4bbl engine and automagic, then GQ1=2.56

Whew!
Again, sorry---i rushed thru my notes and didn't see all the minute details.

Possible conclusions:
1) GQ1 was never assigned a set number because std axle ratio depends on alot of factors?

2) i think if one really wants to know what ratio they got is to bring the vin# to the dealer, they can type it in and tell you exactly which gear came with the truck and then to absolutely verify take the diff cover off and physically count the teeth on the ring and pinion; The oil probably could use a changing anyways.

12-30-2010, 05:39 PM	#19
C-10 simplex Account Suspended Join Date: Dec 2008 Location: indisclosed Posts: 1,515	Re: Gear Ratio ??? Ok, all awake now--i work 3rd shift/night shift unfortunately hence the need to sleep during the day. Also, i'm sorry---i rushed thru my notes and didn't list properly all the info: In addition to the eng/trans combo you also need to know your GVWR rating which is printed on the certification label which should be on the drivers door jam. So, 2nd try, In 81: If you have a 6 cyl and your GVWR is 4900 lbs., AND you're 2WD your std axle ratio GQ1 is 2.73 regardless of which trans you got----3sp, 4sp, or auto. If you have a 6 cyl and your GVWR is 5200 lbs. AND you're 2WD, your std axle ratio GQ1 is still 2.73 regardless of which trans you got---3sp, 4 sp, or auto. Everything same as above and your GVWR is 5600 lbs. you still got 2.73 Now if the GVWR is 6100 lbs. (6100 lbs. in a 6 cyl truck wow) AND you got a 6 AND a 3spd then then std axle ratio GQ1 is 3.08 not 2.73 NOTE: i think it is because if this very reason is why GQ1 was never assigned a set number? If the GVWR is 6100 lbs. and you got a 6cyl and you got a 4spd or auto, then the std axle ratio GQ1 is 2.73. Now for 1/2 ton trucks with small block, *not big block* 8 cyls and 2WD: If you have GVWR of 4900 AND a 3sp or 4sp, then GQ1=2.73 If you have GVWR of 4900 AND an automatic, then GQ1=2.56 If you have GVWR of 5200 AND a 3sp or 4sp, then GQ1=2.73 If you have GVWR of 5200 AND an automatic, then GQ1=2.56 5600lbs and 2bbl engine (check your vin#) and 3spd, then GQ1=3.08 5600lbs and 2bbl engine and automagic trans, then GQ1=2.73 5600 lbs and 4bbl engine and 3spd, then GQ1=3.08 5600 lbs and 4bbl engine and 4spd, then GQ1=2.73 5600 lbs and 4bbl engine and automagic, then GQ1=2.56 6100 lbs and 2bbl engine and 3sp, then GQ1=3.08 6100 lbs and 2bbl engine and automagic, then GQ1=2.73 6100 lbs and 4bbl engine and 3sp then GQ1=3.08 6100 lbs and 4bbl engine and 4sp then GQ1=2.73 6100 lbs and 4bbl engine and automagic, then GQ1=2.56 Whew! Again, sorry---i rushed thru my notes and didn't see all the minute details. Possible conclusions: 1) GQ1 was never assigned a set number because std axle ratio depends on alot of factors? 2) i think if one really wants to know what ratio they got is to bring the vin# to the dealer, they can type it in and tell you exactly which gear came with the truck and then to absolutely verify take the diff cover off and physically count the teeth on the ring and pinion; The oil probably could use a changing anyways. Last edited by C-10 simplex; 12-30-2010 at 05:55 PM.