This is a 10-bolt rear end. How many teeth should the ring gear have? How many turns of the pinion to 1 turn of the ring?

Thanks

 

OK, this is going to seem really complicated, but... if you have 3.73 gears, the pinion will turn 3.73 times for each rotation of the wheels.

The most certain way to tell what gears you have is to pop the cover off and look. Factory gears have the teeth count stapmped in the edge of the ring gear. 3.73 will be 11 & 41. Doesn't matter what kind of rear it is, numbers are numbers. Since gears can only have whole numbers of teeth, the ratios are always 2 whole numbers; usually at least one of them is a prime number. 3.42 is 12 and 41, 3.08 is 12 and 37, 4.10 is 10 and 41, 2.73 is 15 and 41, etc.

------------------
"So many Mustangs, so little time..."
ICON Motorsports

 

if the gear is factory, it should be RPO GT4

------------------
84 Z28 L69. 5 speed with 3.73 posi (broken)Ported heads, intake, 10:1 comp. 230/230 .480 lift cam @.050" w/108 LSA

Triumph Spitfire SCCA roadracer. 1.1 liter 4cyl w/ 14:1 comp.
Outcorners anything!

 

if you have a 700 r 4 trans you can get onto the highway, bring it up to 75 MPH and keep it in D rather than OD, your tach should read out 3,730 RPMs.

 

Well RB83L69 was correct in saying that if they were GM gears, the ratio would be stamped on the ring gear. It turns out that the rear is actually a 3.42 ratio. This rear was behind a TH-350 and the rpms were around 3250 at 65 which I though was real high, and to find out they are only 3.42, I would hate to see what driving with 3.73s must be like.

 

3:73's aren't that bad... sure i have some strange vibration at 80 MPH since i installed the rear but the get up and go.. especially now that its cooler out is AMAZING! When i don't have my lead shoes on i can still get the same MPG that the 2:73's had ok, ok, so that doesn't happen very often.. but it does happen!

------------------

• 89 Formula 305 WS6
  All the usual suspension mods
  Custom Flowmaster Exhaust
  Tranny Cooler
  Dual gauge pod
  Most "Free" Mods
  3:73, Zexel Torsion Posi
  
  15.559 @ 88 MPH
  (Not good enough)

 

Never noticed that before, the prime number thing...



[This message has been edited by a73camaro (edited November 20, 2001).]

 

Yeah, they use prime numbers as much as possible, because that way every pinion tooth contacts every ring tooth, and no combination of mating teeth repeats itself more often than any other combination. Helps spread the wear as eveny as possible, keeps it as quiet as possible, etc.

------------------
"So many Mustangs, so little time..."
ICON Motorsports

 

does anyone know how many teeth the gears for the 9 bolt 2.77 have. Is the 9 bolt 3.08 the same as the 10 bolt. What I was wondering is: I have 2.77s in the rear that is in my car. I have another in my garage with 3.08s. Would it be possible to use the ring gear from one and the pinion gear from the other to get lower ratio gears than are normally offered for a series 2 carrier on a 9 bolt.

Ben

 

I was always under the impression that the driveshaft method works. I.e, how many times the drive shaft spins vs a single tire spin.

-- Joe

------------------
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
1989 Formula 350 4-bolt mains, Forged .030 TRW pistons, SLP 51010 Roller Cam, Comp-cams roller lifters,
Summit 1.5 roller rockers, World Products Sportsman II 2.02/1.60 heads, Edelbrock TPI Intake,
Cloyes Double Roller, timing chain, Mellings oil pump: 13.5 @ 100.23 MPH

Since close of track : Ported SLP runners, Ported Plenum, AFPR, Autometer 100lbs gauge, A/F ratio gauge.

http://www.joesperformance.com

 

And how's the tire situation with them, bald yet?


3200 is right on for 3:42's and a tb 350.
SSC

 

The only way to be sure is to jack up your car ...make the wheel spin and look in the side of the ring if its a 3.73s it should look like this " 41 11 " if you divide 41/11 you have 3.73 that means 3.73 driveshaft turns per one on the tire

 

it means 41 theet on the ring and 11 on the pinion
thats it