Beefed up Dana 300

[Nightcrawler4x4]

For years I’ve watched different threads on D300 being used stock up to blinged out with crawl boxes. My buddy and I ready to start the process of put one in our Toyota. The thing we’re worried about is breaking the case with 4:1 in the case and adding a Eco box. I bought 2 D300s years ago for a couple hundred bucks with plans of doing a swap one day, one case is cracked has good gears other good case something broken in side. So are half the cases breaking or are they holding up with good cross members or plating them?

 

[skippy]

Any kind of gear reduction in front of a 300 will destroy one in pretty short order. The only way a 300 will survive long term is with JB conversion gears, a stak case and 32 spline outputs. Now you are atlas money... I run a stak 300 in my moonbuggy but the portals downstream take the stress off the 300.

 

[Gravy]

Any kind of gear reduction in front of a 300 will destroy one in pretty short order. The only way a 300 will survive long term is with JB conversion gears, a stak case and 32 spline outputs. Now you are atlas money... I run a stak 300 in my moonbuggy but the portals downstream take the stress off the 300.

I respectfully disagree.

I've ran a box4rocks 231 doubler in front of my d300 for years (11 years). Heavy steel beadlocks 40" tsls. Manual trans. 5.38 gears... Basically all the things that ruin a tcase - I've even sheared a 35 spline 4340 FF rear axle shaft and didn't hurt the tcase.
The only problems I've had were ruining the 231 planetary case dry when I hit it on a rock.

The 300 internal are miles stronger than a toyota tcase and those last fairly reliably with doublers and toyota motors.

A 32 spline output isn't as expensive as an Atlas (I have an Atlas in my other Jeep) and will definitely give you peace of mind because generally a toy ujoint will fail before a 32 spline output. I will add I use 1310 ddriveline ujoints as my fuseable link. I'd rather pop a ujoint than anything upstream or in an axle.

 

[Nightcrawler4x4]

The case is fully built with JB 4:1, Hd front and rear outputs it even has 27 spline input. More worried about the case but I’ll build a good crossmember to tie into.

 

[Greg]

I had a Dana 300 transfer case that I was going to build up in my current project and was also concerned about the case strength. My thought was to have the case cryogenically treated and see if that could help strengthen it up a bit more.

Beyond that my next step was to buy a completely new fabricated case from Behemoth. It sounds like the guys from Trail Hero are also going to be building a replacement case for the Dana 300, from what I've heard.

 

[Nightcrawler4x4]

Who are the Trail Hero guys?

 

[Nightcrawler4x4]

I googled Trail hero I knew what that was but I did see the wooden case on the FB. Maybe it’ll be cheaper than the Behemoth. Weren’t the replace a case under $1000.

 

[skippy]

I googled Trail hero I knew what that was but I did see the wooden case on the FB. Maybe it’ll be cheaper than the Behemoth. Weren’t the replace a case under $1000.

I can say with almost certainty it will cost.more than the behemoth but the behemoth shifters are a joke so the case is pretty much worthless.

 

[Nightcrawler4x4]

I’ve been following Midnight Metalworks Rock Box D300 replacement case since April and it’s looking like it’ll be out soon. Unfortunately my buddy did the preorder on the Behemoth Colossus and it came in a couple weeks ago, I shouldn’t say that cause I haven’t seen it yet. After watching the little video on the Behemoth website I’m not sold on the shifting rails looks kinda hokey. I’ll get some pictures of it and see what you guys think. Luckily the D300 we bought came with cable shifters so that will work with the Colossus if we go that route.
The Rock Box looks like the old Stak Replace A Case with shifting like a D300.

 

[Nightcrawler4x4]

Still haven’t had time to do the swap yet and want to go wheeling next weekend but the rear case broke last time out. It’s a top shift and I have two front shift spares.
Can the front shift be moded to work as a top shift?

 

[I Lean]

Still haven’t had time to do the swap yet and want to go wheeling next weekend but the rear case broke last time out. It’s a top shift and I have two front shift spares.
Can the front shift be moded to work as a top shift?

Yes, you can swap shift rails and stuff to make it top shift.

 

[Nightcrawler4x4]

Cool thanx we’ll get into it on Saturday. Apparently your not supposed to rock crawl in reverse while pulling a Jeep.

 

[Nightcrawler4x4]

Short bolt and torque in reverse I guess don’t jive.

 

[Nightcrawler4x4]

Figured out we’re the pin went but have an extra ball. One fell out of both the new and old case while they were being taken apart.

 

[Nightcrawler4x4]

My buddy got it all back together Wednesday and installed yesterday.
I guess one good thing that came out of this is we found out the tranny and tcase are 23 spline.

 

[neagtea]

I have a heavy duty I mput and rear output, I broke the stock output so it was upgraded, The tera gears have not failed yet.
I have a Novak pan on it which I feel probably strengthens the case, right now case is on bench waiting for a front output shaft upgrade, It is now a two piece lol. I blame most of the carnage on sticky tires and stupidiy