Right now I have a 2.73 gear ratio. I think thats a 2 series. If I go to a 4:10 gear ratio, will I have to use a 4 series?

 

3 series

 

No, there are companies (I know Richmond is one) who make low ratios (ie: 3.73, 4.10) for your 2-series carrier . I had 3.73's on my factory 2.73 carrier. You don't need to change your carrier to go to 4.10's. I think they even make as low as 4.56's for the 2-series carrier?

... and before you hear a bunch of "nay-saying" about 4.10's with your A4, don't listen to them!!! I ran my A4 w/4.10's for a couple years and liked them ... gas mileage didn't "improve", but only on long highway trips could I really see a big difference, but my average "combined" city/hwy didn't change much at all. And the 4.10's pull much harder off the line .

 

I agree with the previous post.The general consensus is 3.73:1 is the highest numerical ratio that should be used with an A4 and that is something that I don't agree with.3.73s w/A4 will prevent from having to shift into 4th in the 1/4 mile,so what.When I'm doing a 'high-speed' run and I'm in 4th,the car's still pulling.An overdrive ratio in the trans will not keep the car from continuing to accelerate.I want as much acceleration as possible and gears accomplish that.Back in the 60's and 70's,GM optioned 4.10's,4.30's,and 4.56's as orderable in car gears.Back in the original 'musclecar era',acceleration was the name of the game.I'm currently running 3.23's and my extra rearends are getting 4.56's and 2.73's.4.56's in one rearend for fun and racing and 2.73's in another rearend for traveling.

 

You use a lot of smilies capn pete

The main difference between the 2 and 3 series is the flange position. The 2 series flange is further away from the pinion gear (more towards one side than 3 series). The 3 series gears are thinner, and can break easier (even though the whole ten bolt is weak). Companies do make 3 series gears for 2 series carriers like pete said, but as far as I know they do not make a 2 series gear to go on a 3 series carrier. Another option is to buy a spacer, however you should get longer threaded bolts in that case.

Long story short, just buy any gear you want that is made for a 2 series.

 

They can't make 2-series GEARS for a 3-series CARRIER, because they wouldn't fit together (the ring gear would interfere with the pinion ... they'd never mesh right).

 

I meant making a thinner 2.73 ring gear, so it would fit a 3 series carrier, but yet whats the point of buying worse, right?

 

Most people go with a 3.73 in an A4 because the stock 4l60 can't adequetly handle WOT 3-4 shifts. You'll eventually break something. The 3.73 gear keeps it from making the 3-4 shift in the quarter. If you've got the M6 (which we don't know cause you haven't told us, it might be handy to add a signature about your car), then 4.10 all the way!

Too bad quick change rears are so expensive, huh?! That would be fun.

 

^ ^ You can run upto ~112 mph at least in 3rd gear even with 4.10's in an A4 . Want to go faster? Bump the rev limiter, or run taller tires ... you can still achieve ~130 mph with 4.10's .

And the original thread starter said he currently has 2.73's, so we can only assume he's also got the A4 .

Yeah, a quick change WOULD be nice! That would be great for a street/strip/track car! Depending where you're running, always have just the right gears in there .

 

"Bump the rev limiter" -> and the shiftpoint

 

Shiftpoint for 3-4 can be taken care of by leaving the shifter in 3rd/D .

 

He'll still have to change 1-2 and 2-3.. the shift will need to happen at the right time(the computer does shift points by speed), if he goes to 4.10's the shift points get screwed up. It'll need to shift way way sooner or else the engine will rev' way up before shifting

3.73/4.10's will be a blast either way. I myself am going to go for 3.73.. if I can pass aircare here :/