gearing questions?

Dents · Dec 29, 2007

I had a thought to go with 410 's in the diffs and 4 to 1 in the tcase , But is it better to go as low as possilbe in the diffs and leave the tcase where it is? diffs are 60 front and 14 bolt rear, tcase is a dana 20. the vehicle is a 73 cj5 any input helps thanks:beer:

zukkev · Dec 29, 2007

What size tire? Do you street this rig?:corn:

Cascade_Crawler · Dec 29, 2007

auto or stick?

TreeClimber · Dec 29, 2007

Being a 73 CJ with a D20 tcase, one can assume you've also got a stick shift tranny. Your D20 came with 2.02 low range gears IIRC, and really needs to be a little lower, but really doesn't need 4.0s. On my 79 CJ, I ran a V8 with a T18 gear box, and a D20. I didn't like the gears and eventually put in the Bronco D20 gears which were 2.46s. Worked much better. When I blew that up, I swapped to a Scout D300 with 2.62 gears and that was ideal. I ran 4.27s in the diffs, and 35 inch tires.

cisco · Dec 29, 2007

Tire size is important. If you run a large tire with stock ring and pinion, the drive train can be overloaded from the t-case output flanges to the pinion gears.

Binder · Dec 29, 2007

There are 4:1's available for the D 20?

t1h5ta3 · Dec 29, 2007

5.38's....
any thing else and your fooling your self

Pat · Dec 30, 2007

If its for wheeling then my opinion is you should go low. If you are going to the effort of regearing go nice and low, like 5.38. I regeared from 4.10 to 4.88 and it works good on the street but for wheeling I wish I had done 5.38. Also I believe you can get a 2.72:1 kit for the D20.

Binder · Dec 30, 2007

Pat said:
Also I believe you can get a 2.72:1 kit for the D20.

3.15:1 last I checked unless something new has come out.

Pat · Dec 30, 2007

I stand corrected. It is 3.15:1, also it's about $800. Thats what I get for guessing out my ass.

omc-m38a1 · Dec 30, 2007

cisco said:
Tire size is important. If you run a large tire with stock ring and pinion, the drive train can be overloaded from the t-case output flanges to the pinion gears.

I have 33x12.5x15 with 4.27 gears. A Dana 18 transfer case with 2.46 gears and running a SM465. There is a D30 in the front and D44 rear.
My 17 year old daughter found the week point in the transfer case. It was the low range gear. Got the motor up to 3 grand and popped the clutch.

http://groups.msn.com/ScottMilliner/transfercasecarnage.msnw?albumlist=2

Dents · Dec 30, 2007

tire size is 37 crawlers tranny is t18 and it has bronco gears in the tase already, the tires 60 and 14 bolt are going under it in febuary but im not sure which way to go low in the diffs and leave the tcase or low in the tcase cause the diffs are matching 4.10 :beer:

cisco · Dec 30, 2007

With 37's I'd do the ring and pinion first, other wise you could have increased problems with the U-joints breaking, or other parts in the drivelines.

Dents · Dec 30, 2007

So you would leave the t-case and change out the ring and pinion?How low would you go ?:beer:

cisco · Dec 31, 2007

Dents said:
So you would leave the t-case and change out the ring and pinion?How low would you go ?:beer:

I'm more familiar with toyota junk so not sure on the optimal gearing for a 60. Sounds like a couple people have suggested 5.38's depending on if its a dedicated trail rig, or a little higher if it may see some highway use. 5.29 is a good ratio for 37's in a toy axle. More people will chime in with a similar drive train but it also might help if you described how you are going to use the rig.

Dents · Dec 31, 2007

It is strickly a trail rig,I trailer it where ever i go wheelin.Rieter is my place of choice.:beer:

Damnyankee · Dec 31, 2007

What engine you running?
If your running an engine without may poney's and low torque, go something like 5:38.

If your running a healthy V8 with lots of power, 4:88. the reason i say this is pinion strenghth vs HP. your not gonna need the ultra low gears if you have tons of torque. and a 4:88 pinion is stronger than a 5:38 pinion.
But with a wimpy motor your not gonna be able to motor down the road or crawl rocks without the LOW gears (such as 5:38)

Just my 3.5 cents