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greggbrat

Any machinists out here that want a challenge?

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I would like to put a 4:1 gear to replace the low range gear in my 5sp D/R. Are there any machinists out here that might be up for the challenge of making one?

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I doubt that 4:1 would fit inside the casing, but it's worth a look inside to see. You might still achieve it tho by making first gear a creeper, and modifying the low range as well...

 

GD

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Theres also the fact that the reduction happens before the transmission gears, so a bigger low range reduction would put serious stress on the transmission gears. Probably more than they can handle in the case of 4:1 reduction.

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The divorced transfer case requires a very large lift kit and lots of fab work. The time and expense is much more than I have. It might be time to sell the brat and get something better for off roading.

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If you want cheap - get a Sammi. They can be built up with all sorts of straight bolt-ons and are pretty tough little buggers. Heck - I would get one myself except that I really want IRS/IFS and I can't afford a hummer. Besides that - Hummer's don't have the travel I want anyway.

 

GD

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Too big, Too heavy, and not that great off-road. Although they do look cool. Hard to find parts for, and I doubt you could get one as cheap as a Sammi. A friend of mine got one for $300. Cost him another $250 to get the fuel injection computer rebuilt....

 

GD

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Hey ya'll, just thought I'd bring up that I have two transaxles split apart with me scratching my head trying to figure this one out at the other end. modefying the final drive and all. the ring gear is the easy part. modefying the pinion gear to fit a FT 4wd is the hard part. I was thinking about looking into aftermarket datsun 510 stuff to find the shorter gears actually.

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Finally a "can do" kind of guy. What did you have in mind? Are you looking at upgrading the ring/pinion alone? Or perhaps the low range? If you are planning on changing the ring/pinion then do you also have ideas for the rear?

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Yes - I agree, but the Z car diff's have a bigger aftermarket than ours. If you could make it fit, then you could probably get a 5.xx ring and pinion for it....

 

GD

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That presents another problem in that the highway gearing would probably be too low. The high range on my brat is fine......cruising the interstate at 75mph in 5th gear hits about 2800 rpm. With 5.xxx gears the car might be limited to about 55mph. Hence the better bet is to change the low range gear or regear the entire tranny with first gear being a granny gear with a ratio of about 6:1.

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My buddy has a few scouts. My favourite is his '64 scout 80. Gutless, but is like a mountain goat on the rocks. VERY simple, short, with good overhangs, and nostalgic safari kind of feel. The scout 800s have v8s, and alot more go.

His 78 scout II is very heavy (like 5000lbs) and IH v8s suck, they are big and heavy but gutless, and his rear overhang is worse than a subaru wagon. They also come with sucky gearing in the axles (3.07-3.73:1). They do come with strong axles though.

 

Scout 80/800s rock, so do Samurais, early toyota pickups (friggin indestructable!), or full size heeps (jeeps) /cherokees. I cant think of anything else that isnt ridiculously expensive ie Jeep cj/yj/tj :-p

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And the advantage of changing the low range gear is that it only requires a single change........assuming it can be made to fit in the limited space inside the transaxle.

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I think the guy from australia who rallies his rx has 4.11s in his car, can't remember his name. It might have been a factory rally deal though.

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Might have to cut out the side of the tranny, and tig weld a cover back over the now exposed gears..... anything is possible, but the cost might be pretty high. Unless we could find someone that would do a bunch of them and get a bulk order going. If we just bought the parts and assembled them ourselves it might not be terribly expensive, but getting enough people on board for what is sure to be no less than $500 - $1k for each set is unlikely. Too bad too..... I would really like to see that happen.

 

Oh - and lets not forget the HUGE pile of broken stubs and axles that would result from this..... carnage on a scale that has not been seen before on this board anyway. Rectifiing that situation is possible to... chromoly stubs, and cryo-treated axle cups.... maybe with reinforcing welded to them as well....

 

GD

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I would be happy to spend $500 for a 4:1 low range gear......I could manage the rest of the work myself. Hence why this post is titled "Any machinists up for a challenge". I believe the tranny gears could handle the extra torque as long as you treat it gently. Anyone who has experience with rock crawling already knows that slow and steady keeps things from breaking.

 

With a 4:1 low gear ratio I could probably keep up with most of the Jeeps out on the trail. My brat has great clearance, great traction and reasonable articulation. It just needs more power to crawl slowly.....ie lower gears.

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naw see, I just wanna get back the original subaru engine RPM to speed ratio, now that I am gonna have these monster tires on it. Also for those who run even larger, like 33s, compared to my 28's I wanna drop the final down to around 4.4 to 1, which will make my ride feel like it had the original 22 inch tires on it. I dont want to shred axles, Just make the car acceleration practical on the street not having to use low gear. Also save the clutch too. I was just gona stick with the 1.47 to 1 low gear out of the EA82 p/t 4wd tranny, and the full time aspect of the RX tranny. I believe the RX tranny also has shorter gears than the normal 5 speed too.

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I did some research about the gearing of the various trannys and came up with the following. Unfortunately I dont think you will get enough from any of these trannys to push 31" tires.

Year ............................1st ........2nd ......3rd ......4th .........5th .......Rev .....4wd low

 

1982 D/R.....................3.636.....1.950....1.193....0.769.................3.583....1.462

 

1982 Brat D/R..............3.636.....1.950....1.266....0.885.................3.583....1.462

 

1983-1988 4dr/RX ......3.545.....2.111....1.448....1.088....0.871....3.416....1.196

 

1983-1988 Wagon........3.545....1.947 ....1.366....0.972....0.780....3.416....1.592

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That's not quite right - 83/84 didn't have a 5 speed D/R..... and there is no difference between an 82 Brat 4 speed and any other 82 4 speed. The change in the 4 speed's came in 83, and was across all models.....

 

GD

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Everyone wants to argue with the numbers I pulled out of the various owners manuals printed by Fuji Heavy Industries. Call Japan and argue with them.

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I'm not argueing - I'm telling you that NO EA81 ever came with a 5 speed 4WD of any kind. 83/84 were EA81 years. Period. There's nothing to argue about - I guarantee it.

 

I have an 82 4 speed in my wagon right now - and an 82 Brat sitting out there. Plus an 85 Brat as well. I KNOW the gearing of EA81's. I don't know the gearing of the EA82's as well so I can't comment on that.

 

GD

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