T-18a or any rebuild kit and Terra Flex?

[Hedgehog]

I'm specifically looking for a rebuild kit for a T-18a, but to make this actually not about me, this could be about any American make transmission. Is there a company that produces a superior kit to the others. I prefer American made if it is at all possible.

Here he goes making this about himself.... I haven't got the thing home, but have paid for it and took a much closer look at it. There is some surface rust, but most of what looked like big ugly rust is more rust sludge om the gears. A light rub with a cloth on a screw driver cleans most of it right off he gears. Rob at Willys Works has another T-18a. This one (mine) is far tighter feeling, yes that is a difficult thing to explain, like porn and art, I know it when I see (feel) it. Frankly, I'm getting excited about this.

When considering a Dana 20 transfer case a lot of people are interested in getting a low gear set. When searching for a Dana 20 gear set it becomes clear that being specific about which one is important. Some Dana 20 gear sets are way less expensive than others. $1,016 seems to be a starting point, for those looking for low gear sets, does anybody have a source that is less costly? There might even be another company (give up on Lowmax, that is a "No Go situation) that produces a gear set. All of them look like the Tera Low or TeraFlex offering. Saving a few bucks on this can make a big difference in the project.

Remember, this isn't necessarily for me, it could help a lot of other board members with their build.

 

[HackFabrication]

Get in touch with Parts Mike. He's the T18 guru. Although Mike sold the business a while back, he'll still know what's the best out there. Or Novak. Either would be top of the list for parts/info on the T18.

Dana 20... I put the TeraLow kit in mine. That's about the only commercial kit available for the 20. There used to be another company making gears, but I believe they have long since gone away. There is also the Bronco Dana 20 conversion, but Bronco gears are getting harder and harder to find.

In hindsight, I should have gone with a Dana 300 conversion (or STaK/Atlas). Many more options for them. I would recommend doing the same.

 

[hole]

I went with Novak for the rebuild kit and Lomax for the D300 T-case. I would second Hack with the 300 swap. I've seen D300's on CL for $100-200 and $650 for the Lomax set would have some extra $$ left over to help with the swap.

 

[Hedgehog]

Had a 300 in an '80 CJ5. It performed remarkably well. The T-18 has a Dana 20 attached to it. What would need to be done to switch to a 300? You are right about the additional options available for the 300 and I hear that the Lomax gears are better than the Tera Flex gears.

Even with all the positives of the 300 the adaptor costs $526.02 (Advance Adaptors). So, there is no real advantage.

 

[Torxhead]

You could just bolt in the oem Dana 20 with the T18 tranny and take it from there to see just how much slower you want to go. Also consider the increased torque transfer with that V8 makes it real easy to break stuff.

 

[Hedgehog]

True on the torque. Unquestionably the T18a's compound or granny gear would be a very slow proposition, even slower in low range. That kind of slow is not what I'm hunting. Remember I'm using 3.31 gearing for highway use. Yes, stabbing the t-case into low will add more crawl, but the 3.31's are still tall for sensible off road use. Adding low transfer case gearing allows for the wheel speed, necessary in some mud, sand and ice situations along with first gear torque, leaving compound for necessary situations like...... did I tell you I hate opening gates when alone? We have a lot of gates here in Arizona. I really don't mind opening/closing gates, its the rhythm of doing it alone.... stop, get out, walk to gate, open gate, walk back and get in, drive through gate, stop, get out, walk back, close gate, walk back to CJ, Go. With my '80 CJ & the T-18. Stop, stick it in low range, drop it in compound get out as the CJ creeps along, walk to gate open it, wait for CJ to go through, close gate, jump in stick it in 3rd and GO. Great fun, sort of a game and no worries about live stock getting out.

 

[Lumpy Grits]

My only concern in a '5' is the possible drive-shaft mods need'd to go to the '300'. The 5's rear DS is short enough as is.
LG

 

[Hedgehog]

Is the 300 much wider than the 20? Both have an adaptor, one is factory the other not. Drive shafts will be a problem for me, that is a subject for another thread later on.

 

[Lumpy Grits]

Don't recall what the difference is.
Call Novak, they would know.
https://www.novak-adapt.com/

LG

 

[CJim7]

I dont know the dimensions of a T-15, but I do know that a T18 and it's adapter is almost exactly the same length as a T5.

 

[Hedgehog]

Without question the T-18a/Dana 20 is longer than my current T-15/Dana 20 set up.

BTW - the Novak rebuilding kit for the T-18 is expensive, ~$240. Similar money for the Transfer case.

 

[Lumpy Grits]

Novak is a bit pricey-The quality of the parts are outstanding. None of the Omix China .
LG

 

[Hedgehog]

I wonder who they use? I noticed at the Advanced Adaptor website that their Borgesen steering shaft is $266, about $100 more than I paid for mine, their Dana 20 Low gear set is $150 less expensive than what you can find it elsewhere.

Hack, if you are still following this - You wish you'd gone with the D-300 over the low gears for the Dana 20. Did you have a bad experience? other than more options for the 300 is there a reason?

 

[Lumpy Grits]

They have a bunch of OEM Spicer, Dana and BW stuff.
Their bearings are either NTM or Timkin.
It's been about 4 yrs since I bought anything from'em. Never had any issue.
LG

 

[mtnwhlr]

My only concern in a '5' is the possible drive-shaft mods need'd to go to the '300'. The 5's rear DS is short enough as is.
LG

My 83 CJ5 came stock with a T176 -300 combo.

 

[hole]

If it were me Hedge, I'd be asking guys who just put the Terra-low gears in their 20's how big of a difference it made? There doesnt seem like alot of reduction, 2.4? to 3.15, for +/-$1200. Your new trans alone will make a huge difference.
As your 5 stands your crawl ratio is 24-1
with just the T18 it goes to 49-1
and with T18 and Terra low 62-1
and for s... & giggles with a T18-300 and 4-1 its 79-1
Certainly 62 is better than 49, but is it worth $1200+ ? For not too much more you can have 79-1
When I did my swap I had 29-1 stock and finished with 56-1 . 1st in low range is almost never used now unless there are big rocks to conquer or if I want to **** off my buddies with autos while following me down a steep hill never using the brakes.

 

[Lumpy Grits]

My 83 CJ5 came stock with a T176 -300 combo.

THX-I had forgotten that.
Wonder what the OAL of that combo is compared to the T18/300 setup?
LG

 

[Lumpy Grits]

Hole-I know this is not the same deal. I went from 2.6 to 4:1 in my 300, and it was worth every penny.
LG

 

[hole]

LG, I completely agree, but we gained 1.4 reduction vs just .5 If it was me, I'd start with just the trans swap and see if it suited my needs before spending possibly alot more.

 

[CJim7]

If it were me Hedge, I'd be asking guys who just put the Terra-low gears in their 20's how big of a difference it made? There doesnt seem like alot of reduction, 2.4? to 3.15, for +/-$1200. Your new trans alone will make a huge difference.
As your 5 stands your crawl ratio is 24-1
with just the T18 it goes to 49-1
and with T18 and Terra low 62-1
and for s... & giggles with a T18-300 and 4-1 its 79-1
Certainly 62 is better than 49, but is it worth $1200+ ? For not too much more you can have 79-1
When I did my swap I had 29-1 stock and finished with 56-1 . 1st in low range is almost never used now unless there are big rocks to conquer or if I want to **** off my buddies with autos while following me down a steep hill never using the brakes.

I agree. When I went from the T5 to the T18 it was a massive difference. But I was running 4.10's and 33's at the time so 1st gear felt really low. Even with the 36's and same gearing, the T18 feels good and low.