TerraLow viable opiton?

What about noise?
I've read that the Tera Lows are noisy....

 

Just out of curiosity, what do you have for an automatic? Is there something that will mate up with a V-6 on one end and a D-18 on the other? If this is a possibility, I am thinking of trying to go this route. Or better yet, maybe I should just yank the whole drivetrain out of my Jeep and put something in there complete from fan to rear drive shaft. Then I could sell the current drivetrain complete.

 

This really depends on what type of wheeling your going to do..............47:1 is really not much of a crawl ratio.........just saying. The T-18 or any variant with a 6:00 or more low gear with and OD behind the D-18 makes a pretty capable off road vehicle. Again depends on how you want to use it.

 

The 3.15 terra low has it's plusses and minuses.
The 3.15 reduction ratio provides virtually perfect synchronization for use with most all jeep transmissions.
The 3.15 gears will fit the big hole case with virtually no case modifications.
The 3.15 will require use of a special (expensive) bowl gear on your Warn overdrive unit.
The 3.15 gears will notably increase TC noise.

I think 75/1 crawl ratio is about ideal for most common jeep needs.
Figure 75 to 1 crawl ratio as being the beginning threshold for a true rock crawler.
Anything less than 75/1 crawl is should be considered as a trail jeep.
Example: a 60/1 crawl ratio would yield a highly capable trail rig
A dedicated crawling jeep should use both transfer case reduction and a granny transmission.
Tera low gears plus granny transmission gears will provide 100 / 1 and potentially lower gearing.
A dedicated crawler will want to run 4.89 and preferably lower differential gears.

 

eti engineer - you will need an adapter to the D18 Adapting the Turbo Hydramatic 350 Transmission to the Jeep & IH Dana Models 18 & 20 Transfer Cases

 

I am running the Tera Low 3.15 gearset in D20 case, but I also did the AA tapered bearing conversion for the intermediate shaft. IMHO it's quieter than the old D18 setup I had with the roller bearing intermediate shaft. I had to grind a small flat on the 4wd shifter rod so it wouldn't contact the low range gear other than that no modification to the case was necessary.

AA Tapered Bearing Conversion | EarlyCJ5.com

 

Posimoto, you running a D-18 or a D-20 ?
signature says D-18
I would expect a Tera low D-20 to run quitter without the taper intermediate

 

James, Yes to go from 37-47:1 would really not have that much "bang for the buck" in money being spent..............
If it was me I would again wait until you can get a Low Granny Gear 4-speed in there. ............... like this: 6.32x2.46x4.88 gets you 75:1 in low gear. And still gets you back to where you are now in 2nd gear...........split low gear with the OD and it's 56:1...........back in high gear on the freeway in OD your cruising with a typical factory stick gear at 3:66 final ratio..................best of both worlds.

 

You won't need a bull gear you'll need a bowl gear since you have an overdrive.
On a cj5 you can't have length like you can with more wheelbase (doublers). This will require you to do all you can at every place you can.
Just the 3.15 by it's self gets you 22% reduction. Going from a t14's 3.1 to 6.32 gets 51%.
Looking at bang for the buck and $300 some odd for bowl gear I think you'll find the tranny swap might look better.
Looking at crawl ratio at the goal both wins. Also apply bang for the buck to O'brien's and see what you think.
What I've heard the 4:1 O'brien's only need grinding inside the case. The lower sets need case cutting and welding.

 

I have the Tera Low D18 gears in a D20 case. If I understand correctly, all large hole cases are essentially D20 cases whether they are setup with D18 or D20 gears. D18 gears in a D20 case are sometimes referred to as a Super 18.

 

There is more to the equation that just the crawl ratio. Case in point: 2012 JKU Rubicon with a 76:1 CR and it still absolutely sucks in the rocks. Why? The 3.6L has no usable torque below about 1500 rpms and really doesn't come to life until about 2500. Net result is that I end up slipping the clutch a lot more more in that rig than in the 3B with half that CR on the same trails. The 3B engine will actually idle over just about anything at 500 to 600 rpm without hitting the accelerator or the clutch. Like previously posted, I don't think the Terelows are any more noise than the standard D18 needle bearings. I like my Teralow's but I would have the intermediate gear immediately machined for AA's tapered bearing kit.

Personally, I can not see why the TeraLow's are even offered without that conversion. If one is going to spend $900 for a gear set, another $100 for tapered bearings doesn't seem out of line.