switching to 4.7 gears in crawl box?

[owyheerat]

Newby here and I did search, but wasn't able to find the answer.

I have a slightly modded 99 runner base model, 4cyl 5speed, 5.29 gears with ARB lockers front and rear, Inchworm gear built dual case with 2.28 gears (I wanted a Marlin Crawler crawl box but they were out of stock for over 6 months). Also, have upgraded front CV axles to Lotus heavy duty axles.

My question is can I swap the gears in the crawl box? I would like to have 4.7 gears. If so what specific part(s) do I need to order?

Thanks and sorry if this is a dumb question. This is my first trail rig. I've built it myself, but I still have a ton to learn.

[redneckcustoms13]

Well generally when people built a set up like you are wanting they put the 4.7 in the tcase and leave the crawl box 2.28. The 4.7 in the front will increase torque into the tcase. If you have 21 spline input on your rear case it is significantly weaker than the 23 spline.

If I were in your shoes I would call MC and see what they recommend. I'd think it would be a 23 spline 4.7 kit for rear case with a 23 spline coupler for the crawl box.

[owyheerat]

Ok, good info. I had not considered the added stress (torque) it would put on the stock t-case.

I will call them. I was hoping to get a little education through the forum before I did so, just so I could ask the right questions.

Thanks for the reply and the info.

[Dingman.]

If you converted to passenger drop and running gear driven toy cases I would put the 4.7 in the rear case.

[redneckcustoms13]

I doubt it is converted to pass drop since it's still ifs.

[Dingman.]

I doubt it is converted to pass drop since it's still ifs.

I missed that part.   I feel like in those situations some people choose to run 4.7 in the crawl box in front of the chain driven case without issues.

[owyheerat]

Correct, I'm still running IFS and stock chain drive T-case. Also, I have the 2.7l 4cyl engine which is no power plant. So I don't know if that makes a difference in whether or not it's advisable to run 4.7 gears in front of stock T-case.

Thanks guys.

[redneckcustoms13]

I was under the impression you had went gear drive in a lefty case. I have no clue what to do now. I'd give the guys at MC a call and see what their opinions are.

[owyheerat]

So I finally had a chance to call Marlin (they were very helpful).

I can install their 4.7 XD or competition gear set in my reduction (crawl) box. Yippee!
Worst case scenario if my existing input shaft coupler is the wrong spline count (21 spline), I can purchase the 4 cyl T-case adapter, and it will come with the correct 23 spline coupler.

So, now I just need to get to work....well after the parts arrive.

Thanks to all for your help!