Advance Adapters D18 Low Gear Set.

Has anyone had experience with this setup? I don't see it on their website.

 

Who says they have one? I thought the only vendor was TeraFlex. TeraFlex - Low18 Gear Set Kit - Manual

 

Paper catalog PN 418315 and 418315OD
Probably re selling TeraFlex.
That being said, anyone have any experience with either Advance Adapters or TeraFlex?
A friend tried out the AA and it was so noisy he had to remove it.
I would be interested if I heard some positive reviews.

 

You wanting a Trail Jeep ? or more of a Rock Crawler ?
Can you give us detail about your present drive train ?
Engine ?
Transmission ?
For a Dana 18 ? or other
Differential ratio.
Overdrive or not ?
Might also tell us what model your axles are....

 

Fire road jeep with occasional low gear requirement.
Stock jeep with the exception of 11" front drums and OD.
Strong F134
T90c the one with low ratio first gear
Both 4:27
Saturn overdrive.
A friend here in Napa tried out the low gear kit and sent it back.
I would just like a lower low without changing to a truck four speed.
Too big a project at my age!
Thanks

 

Swap to 5:38 and forget it. You can probably sell your 4:27's and come out ahead on the deal.

 

I was thinking 4.88's but I agree with this statement...should be able to find a matched set of axles and swap the whole thing. Fairly easy job.

 

I'm pretty sure Posi runs a TeraLow kit. Maybe he will chime in.

 

Yes with strong running F-134 and 25% OD you definitely want the older standard (pre 1963) final drive ratio of 5.38.
5.38 plus O.D. will give your meager powered CJ much better acceleration and climbing ability both on and off road.
I always ran my strong running Hurricane with Warn 25% O.D. and 5.38 differential ratio.
One day I swapped in a rear axle with 4.88 differential ratio.
The on road performance was notably decreased.
I switched right back to 5.38 ratio with the O.D.
The meager Hurricane simply cant handle a higher ratio than 5.38 x 25% O.D.= 4.03 Compounded Final Drive Ratio.

Remember there is a reason why Willys went to 4.27 as standard differential ratio in 11/1962.
There also is a reason why Warn O.D. was designated as "Jeep Approved Special Equipment" in 9/1964.
At that time Jeep specifically stated that the O.D. was only to be used with 5.38 or 4.88 differential ratios !

Besides all that ... finding or building a good set of 5.38 axles will probably cost you less than Tera low gears.

 

I am pretty happy with the 4;27s and the OD. Flat land and even slight grades I can keep up with traffic. I would not want lower highway gears. I would like lower off road gears. That's why I was wondering about the gear set

 

Been there , done that.
I certainly can't agree with you concerning the optimum differential ratio for Hurricane engines.
But I also have Tera low experience and can help you in that regard.
Installing Tera low gears will not adversly effect your rig.
IMHO it \will only enhance.

It's most likely (near certain) that you have whats called a small hole D18 transfer case.
The small hole case (3-5/32 index bore) is certainly not a good choice for Tera 3.15 gears.
The small hole case itself will need to be cut open and welded to accept the larger intermediate gear.
The realistic option is to switch over to a large hole (4" index bore) D18.
The large hole D18 will accept the large size 3.15 Tera low intermediate gear.
The T90 must then be adpted to fit the big hole D18.
That will require finding and installing a T86AA / T14 rear bearing adapter ring.

Also you will have to purchase and install the appropriate bowl gear into your O.D. unit.
You can buy that gear from Herm for around $400 alone.
It's going to run about $1500 for everything you will need.
Good thing is that complete drivetrain remains in standard location.

 

The one thing I didn't specify is my tires are 235 75 R15 BFG mud/snows that are about 29" tall, so kind of small diameter.
I can probably find a large hole case. What is involved in mounting the T86AA / T14 rear bearing adapter ring? Do I have to pull the transmission?
I have a service station hoist in my shop so that helps a lot on stuff like this.
I was thinking about a truck transmission from Herm but that seems to require a lot of modifications I don't want to undertake.
What about the noise issue? A good friend bought one of the first gear sets from advance adapters and ended up sending it back due to the noise.
Thanks for your help!

 

I am happy with my high range and 25% OD.
I would like a lower low range without changing to a truck 4 speed.
I am too old for such a project.

 

The rear transmission adapter looks like this. They are pretty easy to find.
Yes on transmission removal. This goes between the transmission and transfer case.
Hmm, could it be done with transmission in the Jeep and transfer case removed ????
I guess very carefully not to disturb the mainshaft and it's needle rollers.

 

I still say it's much much easier, cheaper and better to go with 5.38 axles.
You'll have much increased power band for the Hurricane engine when driving on roads.
Low range will be near 25% lower/slower.
That's virtually the same reduction as going to a Tera flex 3.15 transfer case.

You 5.38 axles can keep the T90 C (3.339 low) and you'll have a 44.2 /1 crawl ratio.
That's a decent low range for a trail rig and the on road performance is notably improved

If you keep 4.27 and add 3.15 transfer gears you get a 44.9/1 crawl ratio.
Virtually identical off road performance.

In this instance the Hurricane greatly influences the optimum gearing because of its meager power band.
If you had an engine that could effectively handle long uphill climbs above 55 MPH it might be a different story.
Your tire size is near standard for a jeep with the Ross steering and a 134 engine.

 

It seems like I remember with the OD engaged I was going 62/65 at 2000 +- rpm
60mph no OD was 2500+- which is kind of buzzy for me.

 

I run the Hurricane up to 3000 RPM or 66 MPH sustained speed with 5.38 gears and 25% O.D.
But prefer to run it about 2700 RPM or 60 MPH sustained.
The reason for running it that hard is because of its meager power.
You must run the RPM up higher than ideal crankshaft velocity in order to achieve sufficient horsepower to operate at hiway speeds.