d20 vs. d300

I have not played w/my Jeep in over 10yrs, but have been thinking about it more and more lately. Back when I built her (15yrs ago) she was a respectable trail rig...

built 360
6.32 T-18
twin stick Scout D20
3.73 D30 - D44 lock rites and font discs
33" mud terrains
Better steering box and pump (forget the brand)
Tom Woods HD drive shaft (rear CV)
Warn 9000lbs winch
Fancy dancy tire/jerry can carrier
Blah
Blah
Blah

When I built her, the X-case 4 to 1 kits were non-existent. Then they came out with the kits for the D300 only. When the D300 kits came out I found myself a 1980 "texas" D300 style bolt pattern Scout T-case that should bolt to the back of my T-18. I also still have in the Jeep, the twin stick D20, that they now have the 4to1 kits for. If you could either which way would you go?

 

If I had both tcases. I would use the Dana 300. Stronger Tcase and more upgrades for it.

 

They have 4 to 1 kits for the 300 but where are you finding a 4-1 kit for a 20 that doesn't require very extensive reworking of the case? Lowest I'm aware of with some grinding is 3.15-1 for the 20.
Regardless, as said, I'd use the 300 as the cases are stronger.

 

To be honest, I have not done much research. I have both cases, and just was curious which was better, and if you where spend the money on....

 

If you put the D18 gears into the D20 case with a certain early 70's Bronco D20 rear slider you get the D18 low range for about $150 and minimal grinding, that's what I paid a few years ago for the rear slider. With my 538's and an NP435 I think my crawl ratio is about 90:1. I believe low range on the D18 is 2.46:1

 

D18 gears in dana 20 is a good upgrade however if he already has the 300 its low range is 262
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If that is a Scout 20 is it the 80s model lower gear ration model? If I remember right it's a D300 with the "Texas" bolt pattern like a D20.

 

Both are good. But the best course of action is to pick one and send the other to me.

 

94:1 vs 74:1...you pick. The 4:1 gears for the scout have had some issues in the past. The 3:15s for the 20 are fine as well......anything over 70:1 is just silly anyway. I think i'll be about 90:1 with my 435/Dana 20 combo 3:15s....so I'll manage to make it work...so I assume you can too

 

I'll have to learn more about this method to change the 4L ratio of the D20! I run 32" tires with 3.73 gears. I like the gears for driving on the road but the 4L just isn't low enough. TerraLow is more than I want to pay.

 

No 4:1 for the 20...just 3:15s or Dana 18 swap....
And without hijackin'....you're not low enough because of the T15

 

A lower 1st and another gear between 1 and 3 would be nice (I think they call that a 4-speed). But my Jeep isn't a hardcore rock crawler so the T15 is OK, I'd just like to lower the ratio of my 4L a bit. The D18 gear change might be worth considering if I ever pull the transfer case for some other maintenance. It's running fine so until I have good cause I'll leave it as-is.

 

I ran a T15/D20 w/3.15/3.73/33s. 35:1 crawl seemed good but I thought more would be better. So I got a 78 J truck T18A, did a Partsmike short shaft kit. That got me to 74:1. I spent the next three years running around in second all the time anyway on the rocks. Even aired down it didn't want to hook up and I just spun out. Not enough momentum I guess. And I had 33x13.5 swampers on bead locks with single digit air pressure for a while. I had a way short/angled rear drive shaft too. If I did it again I would probably leave the T15 and if I needed more I would go higher in the axles like 4:11 or 4:56.