Gear Ratios

[fuelman99]

I have 3.92 limited slip gear ratio in my 05 hemi. Is this a good set for the 1/4 mile or should I look into 4.10s or 4.56s?

 

[03MopaRamman]

Thats an OK set-up to start with but if you decide to move up go 4.56 as goin 3.92 to 4.10 is a waste of dough IMO!

 

[AF_Hemi]

Your money is better used getting traction right now. In the future if you do a gear change go 4.56

 

[Off_Road_Teacher]

Thats an OK set-up to start with but if you decide to move up go 4.56 as goin 3.92 to 4.10 is a waste of dough IMO!

Ask RT-VA, he did the 3.92 to 4.10 swap an he will be the first to tell you that he wishes he had gone 4.56.

 

[truckin151]

Still trying to figure out your wheel spin issues since you shouldn't really have that much of an issue as it stands now. But if you swap out the gears go with the 4.56's

 

[onebadbee]

from what i noticed going from 3.92s to 4.56s is a trade off

3.92s help in the top end and 4.56s help down low in the end the et dont change much in a 1/4 mile cause of the offset

now in the 1/8 its a huge difference

 

[fuelman99]

I ordered some traction bars to start off trying to eliminate the excessive spinning. The only time I need gears for the 1/4 are on the street. All of the tracks we have are 1/8 mile, so 4.56 would probably be a good idea. But my truck is an everyday driver, I know 4.56s will hurt my gas mileage, but how bad?

 

[truckin151]

They don't hurt it at all. Mine went up in the city and as long as im not goin over 75 it went up on the highway by about a mpg too,

 

[AF_Hemi]

4.56 will help your mileage.

 

[lilfroger]

4 Wheel Parts has a hand dandy nifty gear ration chart on their site that shows you the change to RPM's based on tire size & gear ratio. Makes easy to see exactly how gears affect it.

Lift Kits, Tires & Wheels by 4 Wheel Parts

 

[Redtruck-VA]

IMO, 4:56 is the only way to go with our trucks. Especially if you have 33" or bigger tires. I have 30.5" tires and as stated wish I had gone with 4:56 instead of 4:10.

 

[fuelman99]

What brand and where can I buy some?

 

[AF_Hemi]

Motive are pretty popular. Moesperformance.com

 

[Redtruck-VA]

As for differentials, I went with Detroit TruTrac and really don't think there is much difference in quality between Auburn and Detroit. However when installing the 4:56 gear with a DTT there is no pin to contend with so I feel the DTT is a better way to go when using the 4:56 gear. I didn't realize this until all of the recent threads on pin grinding came up. So it does seem DTT has an advantage over the other differentials.

 

[onebadbee]

no clutchs pack or springs in a detroit

hands down better unit

 

[AF_Hemi]

no clutchs pack or springs in a detroit

hands down better unit

thats an opinion.

they're both gonna lock up virually instantly every time. they're both never gonna wear out (i say never loosely -- obviously they will wear out, the auburn a little faster because of the clutch packs, but it takes FOREVER -- longer than you'll be driving the truck thats for sure). the advantage over the DTT? the install like RT_VA said, but then 90% of us dont do our own gear installs anyway, so thats irrelevant. the advantage for the Auburn? Its $100 cheaper.

Auburn won for me and i havent EVER wished i'd gone trutrac.

 

[chefred112]

had 3.92's, changed to 4.56's (loved it even though I was running shorter tires...30"), changed to 4.10s and regretted it..now back on 4.56's and lovin it ever since..