how to find the gear ratio

Silverstanger · July 1, 2003

OK, when my rear end's pinion gear teeth broke off the pinion gear.. it punctured the pumpkin. I jb-welded it and drove home missing 2 teeth in a row, and using 4 wheel drive to help the truck.

On the flat part of the pinion gear (The side of the pinion gear facing the back cover that you take off to get to everything / or the flat top of the tree.. ) -- I happened to notice the markings 41-11 or 11-41 (it was upside down so I don't remember).

That tells me I have 3.73s (41/11=3.727272727272)

Now I was looking on summitracing website for 8.5" ring gear.. since I have a 10-bolt rear end. I only see 3.70 for 8.5 10-bolt and 3.73s for 12-bolt.

The RPO code in my glove box also says GT4 I believe (not 100% cuz some of them I had trouble reading) which stands for 3.73s -- I have a txt file with all of the rpos and what they stand for.

** Can anyone please shed some light on this **

** What is the OEM replacement / aftermarket gearset name brand?? Ford is to Ford Motorsport as Chevy is to XXXXXX ???? **

Professor · July 1, 2003

It is possible you are seeing a 37-10 combination.

Precision Gear Builds it. I put PG in my truck about 100,000 miles ago and haven't heard a peep out of it yet.

http://www.precisiongear.com/gm85.htm

ridnlow · July 1, 2003

didnt read the whole post!!

Silverstanger · July 2, 2003

i don't think you guys understand..

it says 41-11 on the pinion head.

that is 3.73s. not 37-10=3.70

I was on summitracing looking at the 3.70s.. is that what you meant by seeing the 3.70.. hmm ok.. let me know

so where do i get the 41-11 gears (3.73s) to fit this thing. 10-bolt 8.5" ring gear??

varmint2506 · July 2, 2003

so where do i get the 41-11 gears (3.73s) to fit this thing. 10-bolt 8.5" ring gear??

Check out Richmond Gear.

Richmond Gear

hb1 · July 2, 2003

Quite likely you will have to replace the whole pumpkin. I'd go to a local 4x4, or off-road shop, and have them do it. Here in the Denver area would cost about $800 to $1300 (change one or both gearsets). If you need to change 'em, why not go to 4:10s. Better all the wasy around.