Jeep D300 to 700R

[ace138]

I have a 1988 k5 with a 305/700r/np208. What all (parts) would I need to swap in a Jeep D300 behind a 700r?

How many splines is the output shaft on the 700R and how long is it? I really want to get rid of the NP208.

 

[Thunder]

700r4 have 27 spline output.
I dont think a D300 will bolt up to a 700r4 without a 700r4 to d300 adapter kit. They usually come with the needed x fer case input shaft.
Why do you want to swap to a 300? I dont think they are that much stronger than a 208. Yes i know they are a strong unit in a light Jeep But a 5200 LB truck with a V8 is a diferent animal. I think the output shaft in the D300 would be a weak point.
You would be far better off with a NP 205 if you want a strong Xfer case.
A NP 241 will bolt right up to your 700r4. It is a little better than the 208.

 

[wayne]

Yes you can put a D300 behind a 700r4. You can even buy a kit to clock it flat. I am not sure of what will be needed to make the speedo work correctly but I'm pretty sure it could be done. The D300 is plenty strong if you upgrade the outputs. I'm not sure how well the stock outputs will hold up though. The bad thing is the price. If you clock it and buy heavy duty outputs plus 4to1's you wind up with a good bit into it and for a few hundred more you can get a Atlas or Stak.

http://www.jbconversions.com/pages/products/adapters/1001.html

http://www.jbconversions.com/pages/products/lomax/index.html

 

[1-tonmudder]

The 300's are 23 spline input and will need a 27 spline input to work with you trans,and I would highly recommend a 32 spline output as well.You can reuse your 700/208 adapter for the 300.

 

[ace138]

I don't won't to run a doubler or a NP205 (I'm trying to keep the weight down). It sounds like I just need to save up for an A A Tcase. How much do they run? When I buy the Atlas II Tcase, I should ask for one with a 27 spline input?

 

[Thunder]

If you are trying to keep weight down why not just run a NP 241?
Are you putting out huge ammounts of horse power out of your mighty 305?
Are you running 1 ton with 44s"
Do you do hardcore rock crawling?
Do you have thousannds of dollars to spend?
Why do you feel you need an atlas case?

 

[ace138]

If you are trying to keep weight down why not just run a NP 241? - nah, too weak, please I want an all gear Tcase (no chain)
Are you putting out huge ammounts of horse power out of your mighty 305? - Funny
Are you running 1 ton with 44s" 1tons with 38 for now, maybe 42's later
Do you do hardcore rock crawling? Are you kidding, my heavy a$$ Blazer can't even handle the bunny trails without breaking something.
Do you have thousannds of dollars to spend? No, do you? Can u lend me a few Gs.
Why do you feel you need an atlas case? Well, I need something strong, something I can clock up into the frame rails, something with a good low range and light.

 

[Brady]

Look into the Lomax 205 with the 3to1 gear set.Nice and strong can be clocked.$1000 bucks for kit form.Bigger/stronger gears than the atlas.If your breaking parts now the D300 will not last.

 

[Thunder]

Well if you dont have thousands of dollars to spend forget the atlas. They are around $2K
If you think a 205 is too heavy than an Atlas will be too. They are only about 10-15 lbs lighter than a 205.
241 with a slip yoke eliminator are a plenty strong case. There are many people here running clocked 241s with 1 ton running gear and big tires. They do some pretty hardcore stuff with them.
241 has a stronger case than 208 and a 2.75 to one reduction. It is about the lightest, strongest, best geared t case you can easily/cheaply bolt up to a 700r4.

Even if you spend the $$$ to beef up the internals on a D300. I still dont think it will last long on your truck with big tires and 1 ton stuff. They have weak cases and have been known to shatter under too much load.