BEST WAY TO GEAR DOWN

Joined
May 1, 2003
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I have an 81 fj40 (split t-case) and am looking for input on the best way to lower my gear ratio.  I'd still like to cruise down the highway but also have plenty of gear on the trail.  (33's w/ 4" lift, stock 2f) I've been looking into the t-case low range replacement gears ($1400 for gears only) There has to be a better option, but like every problem I have, I get different answers from different people and I need more input.  Should I buck up and shell out the cash, go for the non-us tranny, or just jump ship and go chevy.  Any experiance would be helpful, people talk, I need to hear from people who have.  
thanks!
 
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Mar 27, 2003
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Swap out your 3.7 diffs for earlier 4.1 diffs nets you a cheap 10%.

Talk to Marlin about dual t-cases or lower transfer gears. With money, everything is possible. Just decide what you want before you open your wallet and pick up a wrench. Keep in mind that you may decide 33s are too small . . .
 
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Wouldn't a SM420 go on an 81 as long as a 3 spd transfer, and 3spd bellhousing was used? I believe so, and that means a 7.05:1 first gear. &nbsp:Doesn't get much better than that. But since you are used to a nice shifting 4 spd, a rough non-synchro first geared-Sm420 might not be desirable. Read some of the tech writeups and see what you think. Sm465 might be smoother, but I'm not sure cause I haven't done research on a SM465 since I'm going for an SM420.
 

megolfer

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Youy could also go woth the new Advance Adaptors orion T-case. It is 4:1 and if you preorder now you get it for $1300 and its not a aluminum case its steel or something a lot stronger. I am doing a sm465 trnnny swap as we speak. Its pretty easy and it will be a lot better shifting than a sm420. Its got a 6.51 or something close to that first gear.
 

woody

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For a bolt-in swap, the Orion t-case from AA seems really nice, and well priced....problem is, I believe the 81 will have the split t-case and the Orion is designed for the older pre-split cruisers.

The other issue is strength and driveability....IMO, the Marlin doubler might be your best route....$1500 or so and you get selectivity in gearing, either single low or double low. Only other issue is you'll need d-shaft changes, your rear shaft may end up fairly short, and you'll need a custom mount for additional driveline support.
 

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