Different diff ratios

[natvet]

OK dumb question but I have to ask. ...Be easy ya'll..... Would cause problems to have 3.7 ratio in rear diff and 4.11 in the front diff. I am guessing it is no big deal but now i will know.

Thanks alot

 

[Mr. Toad]

Do NOT drive your truck in 4wd with different ratios unless you wish to grenade your transfer case.

(It's OK to drive it this way in 2wd)

 

[robj]

X-2

 

[jtoro]

Different gear ratios will not work together unless you find a way of placing a differential between front and rear. Wheels in front axle would go at a different speed than the rear ones, which would spell trouble. Same goes with different size tires in front and rear.

 

[zuluzeugma]

I've seen some rednecks do it if they are close enough. Its a bad idea, but as long as it will only see really loose dirt, its a temporary solution. I saw a 1/2 chevy like that once; faster rear gears than fronts. It tried to get in front of itself if that makes sense; it fishtailed down the road with any acceleration at all.

You could really redneck it and make it up with different size tires. 3.73 with 31" is pretty close to 4.11 and 33" haha...

 

[KOOTENAY KRUZER]

I've seen some rednecks do it if they are close enough. Its a bad idea, but as long as it will only see really loose dirt, its a temporary solution. I saw a 1/2 chevy like that once; faster rear gears than fronts. It tried to get in front of itself if that makes sense; it fishtailed down the road with any acceleration at all.

You could really redneck it and make it up with different size tires. 3.73 with 31" is pretty close to 4.11 and 33" haha...

Some farm tractors and construction equipment do exactly that - different tire sizes front and rear compensated by differnt ratios front and rear.

IIRC some older models of H**P had slightly different front and rear ratios. You do not want to see pavement or even good firm dirt with you transfer case engaged in 4wd, though.

 

[JOSHCRUZER]

I know around here the mud trucks put a different front end gear ration to allow the front tires to spin faster. These truck are mud racing only and pretty much just go straight.

 

[natvet]

Diff ratio

Thanks for the answer guys. Anyone want to trade front and rear thirds I have 4.11s looking ofr some 3.7s

 

[Vicm]

I keep hearing 3.73 for LC gear ratio is there such a thing??
The only ratio I have in all my differentials is 3.7

I will trade you PM me;;; because I want to run a 4.1 rear from a toy truck and I need a 4.11 diff for the front.

 

[zuluzeugma]

I'm bored at work today so I threw this really quick spread sheet together to show what I was talking about. I know its redneck, but you can get really close with different size tires. I know the graphics suck (I really need to get a silver star). If you care enough, PM me your email address and I'll send you the actual spreadsheet I made. I know there are a million gear calculator in the net already but I've never seen one that would plot it all side by side. This plot shows the most common 12 gear ratio/tire size. The actual spread sheet has a 13th column for your choice if you want to play with 5.29 and 40" tires, but at that point, you're probably not worried about on road speed.

 

[JackRabbitSlim]

been there done that in my pick up. stay off pavement

 

[1v6pony]

Does anyone know if Vicm is right with the photo he has posted, There are other numbers on the ring gear also... I also am trying to ditermine my ratio and ring gear size on my axel

the number on mine are 9X37 @ 72 4 26 S 854 1

I bought this used and want to install a locker in them, They are supposed to be early to mid 1970's axles

The locker I want to insall say's it is for a 1969-1989 8.875"rg and 30spline count. The spline count is correct but what a bout the ring gear size?????

Thanks everyone
Brad

 

[Mr. Toad]

Your ratio is 4.11, which corresponds to mid-70s cruiser diff.

The LC solid axle ring gear was 8.875"

 

[1v6pony]

Great.. Did you get that from the numbers that I posted, could you explaine so I know how to do it in the future...

Thanks
Mr Toad

 

[Mr. Toad]

I got the ratio from the numbers (ratio=37/9). The other popular factory ratio (for FJ 60s, I believe) is stamped on the ring gear in the picture: "10X37", or 37/10=3.7 ratio. The other #s on the ring are greek to me, but I'm sure they're there for a reason.

I know the size of the Toyota ring gear because of some old research I did. I think it's probably in some of the tech links here too, but I'm too lazy to look it up right now.

 

[1v6pony]

Thanks for clearing that up for me now I will look like I know what I am talking a bought in reguard to ratio ID.....

 

[natvet]

Zulu
[If you care enough, PM me your email address and I'll send you the actual spreadsheet I made. I know there are a million gear calculator in the net already but I've never seen one that would plot it all side by side. This plot shows the most common 12 gear ratio/tire size. The actual spread sheet has a 13th column for your choice if you want to play with 5.29 and 40" tires, but at that point, you're probably not worried about on road speed.[/quote]

Dude that is awesome I would love the spreed sheet. Email is natvet@austin.rr.com. Thanks alot.

 

[bsevans]

Your ratio is 4.11, which corresponds to mid-70s cruiser diff.

The LC solid axle ring gear was 8.875"

Mid '70s 40s are 4.10 not 4.11.

 

[malcb]

Mid '70s 40s are 4.10 not 4.11.

That would be 41 and 10 teeth?

Axle code might be something like K292 for an open diff while K082 is 4.11 open, both wih 9.5" ring gear (according to the TCL FAQ)

Thats a point, I thought, and the FAQ says LC are ring gear are 9.5"

 

[Mr. Toad]

Mid '70s 40s are 4.10 not 4.11.

Negative.