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Dana 300 doubler

Blt2rok

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Joined
Feb 28, 2021
Member Number
3588
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17
Who here has doubled a toy case to a Dana 300?
How do you like it? Has it held up to front digs? Has the front axle held up?

I've had a couple trucks with Toyota doublers and never had a problem. This new one I've got I'm thinking about putting a 300 in it. I'll end up having to run my 4.7 gears in front of it not sure how much difference that makes in reliability, and I'll have a Dana 44 instead of my usual toy axle but it's gonna get rcv's and the jantz jana k4 setup in it.
 
Who here has doubled a toy case to a Dana 300?
How do you like it? Has it held up to front digs? Has the front axle held up?

I've had a couple trucks with Toyota doublers and never had a problem. This new one I've got I'm thinking about putting a 300 in it. I'll end up having to run my 4.7 gears in front of it not sure how much difference that makes in reliability, and I'll have a Dana 44 instead of my usual toy axle but it's gonna get rcv's and the jantz jana k4 setup in it.

I think it was white shadow on the old forum who seemed to have tons of issues with his toy to D300/atlas adapter.

I don't think I would put a 4.7 crawl. Box in front of the D300, just asking for trouble. Just do the 4:1 gears in the D300.

If it's a waggy or chevy D44, the rcv's are smaller than Toyota 30 spline Birfs FYI. The jants kit is waste of money, you'll break everything else before the R&P.



What's your goal? Just front dig? Shorter drive train? Stronger tcase?
 
Yeah just front digs mostly and I've never done it before. I already have the 4.7 toy case so that why it would be in front. It becomes cost prohibitive if I put 4:1 gears in the 300 just to play around spinning the front tires with a pretty good chance of killing the front axle. Thanks for the advice.
 
You can always use a rear disconnect on a toy case and save some coin that way.
 
4.7 into a d300 is a great way to break a d300.

Idk why people throw so much $ into d300s.
Ive replaced more 4:1 gears in d300/d20s than anything else.
 
Interesting, I've personally destroyed my fair share of 4.7 gears. The best so far has been the marlin set. I'm currently putting together a 241/d300 combo mated to a ax15 with 3RZ power. Was hoping this setup would last longer/ tougher. Guess time will tell...
20220516_190311.jpg
 
Interesting, I've personally destroyed my fair share of 4.7 gears. The best so far has been the marlin set. I'm currently putting together a 241/d300 combo mated to a ax15 with 3RZ power. Was hoping this setup would last longer/ tougher. Guess time will tell...
20220516_190311.jpg
what are the rations of this, is it dual 2.76 or something like that?
 
2.72 for the front 241 half and 4.0 low max gears in the d300. It still gives me the super low that I'm used too when all compounded. Just got tired of rebuilding toyota cases. This set up is shorter then running my old r151 to toyota doubler.
 
4.7 into a d300 is a great way to break a d300.

Idk why people throw so much $ into d300s.
Ive replaced more 4:1 gears in d300/d20s than anything else.
Are the gear seats that break usually Teralow? Teralow gears seem to always break
 
i ran my trail gear 4.7 case and the 2.28 case in front for 5 years i think, and i never had even so much as a leak from that thing. the last two years i was on tons with 7.17 so that took alot of stress off the cases but the first few just 4.10s and let the beat down begin
 
4.7 into a d300 is a great way to break a d300.

Idk why people throw so much $ into d300s.
Ive replaced more 4:1 gears in d300/d20s than anything else.

If you add up all the upgrades, it's literally cheaper to go atlas right off the bat.

Lots of things are that way though, but we end up doing it one part at a time, because most can come up with $200-500 here and there, yet $4k at once is kinda tough to swallow.

D300 is a good case for lighter rigs with lower power.

Yeah just front digs mostly and I've never done it before. I already have the 4.7 toy case so that why it would be in front. It becomes cost prohibitive if I put 4:1 gears in the 300 just to play around spinning the front tires with a pretty good chance of killing the front axle. Thanks for the advice.

It's not a bad option if the adapters have gotten better.

I would not run 4.7 in front of the D300 though. Sell the gears and get low max 4:1s. I actually think 4:1 would be a better gear anyway.

Or just pick up a disconnect for a Toyota case.
 
I'm collecting parts to build one now. My friend has one and trashed the bearing in the to adapter after a few years. He did a 3rz, w56, toyota 2.28, to a D300 with 4-1's outputs. Rarely used it to digs though, he always complainedit wss hard to shift. It was in a buggy with tons and red labels for several years.

I wouldn't but the crawl gears in the front case. I puts a lot of stress on the rear case.
 
The other option is just a selectable rear. Open rear, locked front can maneuver well and is quicker than shifting the front in and out. I remember a big name werock driver saying they used it more than front dig.
 
The other option is just a selectable rear. Open rear, locked front can maneuver well and is quicker than shifting the front in and out. I remember a big name werock driver saying they used it more than front dig.
That with a cutting brake is probably perfect.
 
That with a cutting brake is probably perfect.

I ran it in my 1 ton 4runner for about a year and really liked it. Wanted cutting brakes, but never got around to it. I'd just leave the rear unlocked until I needed it, you could use rocks or trees to pivot off of.
 
I ran it in my 1 ton 4runner for about a year and really liked it. Wanted cutting brakes, but never got around to it. I'd just leave the rear unlocked until I needed it, you could use rocks or trees to pivot off of.
I've never thought of this. I like it though.
 
The other option is just a selectable rear. Open rear, locked front can maneuver well and is quicker than shifting the front in and out. I remember a big name werock driver saying they used it more than front dig.
I have a detroit in back and use my cutting brakes with it. You can bump the brake and it'll just put enough drag on it to feel but not lock the detroit. Of course if you just mash the handle it's pointless.
 
I've never thought of this. I like it though.

It's not perfect, but neither is front dig, sometimes it will just drag the back end around. Each has its pros and cons, hence the we rocks guys having both.

For me the selectable rear is more useful since I can also unlock the rear for street driving or snow side hills.
 
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