T98 VS Terra low 3.15

after 7 years of trail riding with a totally stock cj3b I broke down and put in a roll cage and 34 950 15 tsl swampers. I like the added ground clearance but I am too fast in low now.
My question is, do I put in a t98, or get a terra low? I understand the ratio difference But how low do I need to go? I have a t98 with the right input shaft and the bearing retainer but no front adapter, I have the rear adapter, but the output shaft although the right length, has 10 splines not six . no one seems to know what the trans came out of with the 10 spline out put. I have a correct t18 output shaft but they are slightly different and i dont think it will fit.

I just dont know if it will be worth all the work to swap in the t98(drive shafts , pto shaft ) plus the loss of ground clearance. That t98 is big compared to my t90. Sorry so long but I want some opinions.

I promise to take some pictures in august on our trail ride and post them .
Thanks ,
jon

 

I use my jeep primarily on trails, rocks and mud, I know the t98 is bullet proof but how much can you damage with an f head?

 

short version. Keep the T90 and go with the Tera-low. The T98 is too big and tall. You will loose ground clearnce and spend as much in modifications as the Tera-Low, both of which you already stated. Long version: I went through this same escalating string of modifications. Tires,safety equipement,gears,suspension and now completing a 225 conversion. While I am happy with the changes, my advise is, keep all changes simple and you will be happier in the long run. My personal choice was to sell my complete T98a. See articule on CJ3B website about T98a transmissions. I decided in favor of the O'Brian Rockeater 4.86 Mdl. 18. Expensive, yes but my 3A is a whole different rig because of it, and no modifications. Second or third gear are the norm but 1st is great in the techical rock stuff. By the way, Willys tech had factory T98A adaptors listed for sale. Good Luck

 

I want to keep it simple, thats the thing. how much was the obrien kit? where did you get it.

 

The O'Brien is high quality craftsmanship but more money and worth it. I have a T-18, Dana 20 with your 2.46:1 low range and 4.56 gears. I only use 1st and 2nd gears on the trail.

 

I just got off the phone with mister o brien. Very interesting. I guess it is going to come down to $. I would like to get his gear set and leave my t 90 in my jeep , smaller lighter etc.,But, I already have the t98 At this point I only need the front adapter plate, and to make some driveshafts. I know I could sell the t98 to help fund the gears but he is talking $2400 for the 4.86 to one gears.

I am starting to think I should just go back to my 700 16 ndt tires, If I put the t98 in I will loose most of the ground clearance I gained with the 34 950's

I dont want my jeep to turn into a JP magazine project ,42's rockwells ,etc!!!

 

For that amount of money, you can buy a T18-D300 adapter, change the D300 to 4:1, install a centered rear axle and your T98 (assuming the T98 will work with the T18 transfer case adapter).
6.40*4.0*5.38=138:1 crawl ratio.

Either that, or compromise with a Tera kit and a somewhat shorter tire.

 

I know! But see here we go, Why dont I throw a ramjet in there too! how about yj spring over? Rock ram steering, High pinion 60's
etc. You know If I had a job I wouldn't have all this time to think about this stuff!

 

Jon, you dont mention which diff gears you have. I've driven a CJ with 4.88's for a long time and when I get in my brothers CJ with 3.73's I keep trying to shift one more gear below 1st. Especially with the 33's on it. A lot of what you are experiencing could be just that you arent used to the slightly higher gearing with the taller tires. Perhaps you cold drop down to a 33 or 32" tall tire too. Although I've gone from 29's to 33's and it didnt seem like that big of a difference to me.

 

I have 5.38 axle gears. cant go much lower there.

 

Jon, this contact ( Dmeach@aol.com ) was given on the WillysTech site for T98a adaptors. He might have your missing part. I found the T98a 's value to be more to a restorationist than to me. I sold it for $900., it was complete. Maybe you could get a good price for yours and pay for the TeraLow 3.15.