Lower Low Range

[COH143]

The weak point in my 93 YJ right now is the 2.72 stock low range in my NP231 T-case. I am looking to get down to a 4.0 low range so I don't have to use as much wheel spin to get up obstacles as I do now. Don't get me wrong: wheel spin can be fun and I am not against using the gas where needed (and where not needed sometimes).

So I am looking at three options: Atlas II transfer case ($$$); Tera low 231 kit on my existing NP231 transfer case ($$); or swap in a used transfer case that already has a 4.0 low range ($).

So, what does every one recommend and why? Lets hear it. And thank you in advance for your opinions as they all help.

[Frank]

I hear the Tera Low kit is pretty straight forward on the install. I think its 3.15x1 unless they have a 4x1 now. A RockTrac out of a Rubi would be sweet , but you have to find a donor or someone that has an upgraded drivetrain . What do you have for axle ratio as that can help also. Everyone seams to be in the 4.56/4.88 range with a 4x1 and 33s or 35s. We are gonna miss the gityup part ! FjR68

[ZAEDOCK]

I think the AX15 is more of a weaker link than the NP231. I think having a granny gear (L) with normal 1st (2nd gear) offers more options on trails.

An NP435 would make a nice swap. IIRC, using CJ parts, the only custom components would be a pilot bearing and t-case adapter.

If you're looking for simplistic, finding an already 4:1 231 would be the way to go, with the next option being a kit. The Atlas would be awesome, but $ ching.

[Kurt]

Foy myself I opted for the NVG241OR out of Rubi's to put in my 92 YJ & 97 TJ.
To build up my existing NP231's with the TeraLow and a wide chain would have cost more than used NVG241OR's.
I preferred the NVG241OR due to it's strength over the 231. Also I've read that some have had issues with the TeraLow.
From what I've read the TeraLow's if accidentally over-rev'd may destroy themselves.

If your not in a hurry I'd recommend you keep your eyes open for a Rubi case. They pop up for sale now and then.

[ChrisD]

Or just buy Doug's jeep

[COH143]

Current set up is 4.56-gears, 35-inch tires, and mostly stock NP231. the Tera Low kit is 4.0 and comes with the over rev warning so that is a concern.

[DOUG]

Or just buy Doug's jeep

Kellys Jeep, mine is not for sale.

If you have the $$ go for a 3 speed Atlas or Monster Box. Both will give you multiple options.

[ChrisD]

I thought it was a 4:1 low range???

[DOUG]

I thought it was a 4:1 low range???

Atlas can be had with mutliple gear choices. Made a mistake...not a 3 spd, it's a 4 spd case.

[Frank]

I have the lomax Gear set 4x1 in my 300 . It was a 100.00 less than TeraLow and its built with billet gears , not a ring gear pressed on to a hub and welded together like the TeraLow. Which turns out to be the weak spot. Looks like a Rubi T-case is the better plan. FjR68

[ZAEDOCK]

I think I'm going with a 203/205 doubler. Depends on the engine I run....

[IronTortoise]

I have the Tera low 4:1 conversion in my YJ. I am satisfied with its performance. I do have to be concerned with over-reving and am careful not to exceed 2500 RPM in low range. With the 5 speed manual transmision I do not find that to be a major problem. Install was done by my friend Bob Tochio at Pauls Transmision in Hingham. I see you are in the next town over in Cohasset.

[ZAEDOCK]

I am careful to not exceed 5000 RPM. Sometimes.

[nostaw]

I would spend some time looking for the Rubi case... They aren't all over the place, but they're not impossible to find.

JW

[Kurt]

According to www.car-part.com this place has one listed for $1,000
http://www.lindersinc.com/index.htm