NP 231 Tera 4:1 failures?

[willness33]

I'm considering my options for some deeper gearing at this point in my TJ. I can't go any lower with the axles without swapping at least a D44 in the front. This leaves me with some thinking about t case options. An Atlas or Stak is what I want, but I just moved into a new house and the money tree hasn't budded yet. I have a D300 that I could build/flip, but have heard of more problems than not with that. Lastly, I'm considering the Tera Low 4:1 kit for the 231. I personally know of one failure where the planetaries grenaded, but there are a whole shit ton of these things out in the wheeling world. Has anyone else seen any failures or does anyone have one to sing it's praises?

 

[catfishblues]

Forgive me for seeing the irony in your post, but you're running stock axles and you're worried about grenading a D-300?!? I think the axles are likely going to go before the case does. I don't really have an answer to your question, but I do have something else for you to consider. If you drop a geared case in front of those axles, the axles are suddenly going to be seeing significantly more torque than they were before. You'll probably start seeing breakage where you weren't before. You may want to consider the D44 upgrade first.

 

[willness33]

Forgive me for seeing the irony in your post, but you're running stock axles and you're worried about grenading a D-300?!?

Nowhere did I say grenade the 300. I'm talking more of issues regarding the shift linkages and leaking. Flipped 300s leak about 50% of the time from what I've seen and the linkages can sometimes be problematic. Also, yes I would break a stock output shaft on the 300 with my current setup so the 32 spline upgrade cost would have to be figured in. As would the flip kit, 4:1 gears AND the 21 spline input. Granted, the torque would be more significant on the axles with a lower t-case, but when you have 2.5 liters of goodness to begin with, there aint much torque to multiply. The D30 on my jeep is my known weak point. I can swap axleshafts on the trail a whole lot easier than repair a blown planetary on the t-case.

Also, while I may be running a geared, but otherwise stock front axle, the rear is an 8.8.

To make this thread easier to follow, I'll ask a simple question. Who has a NP 231 Tera 4:1 gear set? Are you happy with it or has it given you problems?

 

[89wrangler]

I am on my second 4:1. When they say do not run at high RPM, they mean it. I toasted the planatary's in the first one. This was after 2 1/2 years of a lot of high reving, and running 4/5th hear in low range on the trails a little too much. Called them, explained that I might of been on the high side of rev limiter a few times but thought it should not have let go the way it did. They agreed ( or got tired of me whinning) and replace unit for $250, which I thought was really generous seeing it was out of warranty. I think it is a great upgrade for the 231 especially if you are running a HD SYE. I am running a mildly built 360V8 with 14B/D60 and 42's. I now run high range on the muddy days or places where I need a lot of RPMs. I would recommend it Sam's Off Road a lot of times have blems for sale with full warrenty for around $700 great price

 

[willness33]

I am on my second 4:1. When they say do not run at high RPM, they mean it. I toasted the planatary's in the first one. This was after 2 1/2 years of a lot of high reving, and running 4/5th hear in low range on the trails a little too much. Called them, explained that I might of been on the high side of rev limiter a few times but thought it should not have let go the way it did. They agreed ( or got tired of me whinning) and replace unit for $250, which I thought was really generous seeing it was out of warranty. I think it is a great upgrade for the 231 especially if you are running a HD SYE. I am running a mildly built 360V8 with 14B/D60 and 42's. I now run high range on the muddy days or places where I need a lot of RPMs. I would recommend it Sam's Off Road a lot of times have blems for sale with full warrenty for around $700 great price

Great info. Thanks!