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Discussion Starter · #1 ·
I heard that an auto t case has lower gears for low drive ???
So can I put them into my mua5 t case ?????
It would be a significant reduction !!! Yes /No ???
 

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It is not a big difference to warrant the work. For the price of the 3:1 Revolution gears I would get them if I was going to be ripping the case open.
 

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DISCLAMER: I'm good but not perfect, on mph conversions I've rounded up to the tenth of an mph. If there's an error its to the right of the decimal point.
An insert of my previous musings on gears...
(Crawl ratio = Motor Rotations : One Tire Rotation)

Single Case
1{eng}*3.767{man. 1st}*1{man. t-case high}*4.56{diffs}=17.177:1
1{eng}*3.767{man. 1st}*2.28{man. t-case low}*4.56{diffs}=39.164:1
1{eng}*3.767{man. 1st}*2.66{auto t-case low}*4.56{diffs}=45.692:1

Single Case W/Revo Gears
1{eng}*3.767{man. 1st}*3.07{man. t-case Revo}*4.56{diffs}=52.734:1

Dual Cases
1{eng}*3.767{man. 1st}*1{man. t-case high}*1{auto t-case high}*4.56{diffs}=17.177:1
1{eng}*3.767{man. 1st}*2.28{man. t-case low}*1{auto t-case high}*4.56{diffs}=39.164:1
1{eng}*3.767{man. 1st}*1{man. t-case high}*2.66{auto t-case low}*4.56{diffs}=45.692:1
1{eng}*3.767{man. 1st}*2.28{man. t-case low}*2.66{auto t-case low}*4.56{diffs}=104.178

Dual Cases W/Revo Gears
1{eng}*3.767{man. 1st}*3.07{man. t-case Revo}*1{auto t-case high}*4.56{diffs}=52.734:1
1{eng}*3.767{man. 1st}*2.28{man. t-case low}*3.07{auto t-case Revo}*4.56{diffs}=120.235:1
1{eng}*3.767{man. 1st}*3.07{man. t-case Revo}*2.66{auto t-case low}*4.56{diffs}=140.275:1
1{eng}*3.767{man. 1st}*3.07{man. t-case Revo}*3.07{auto t-case Revo}*4.56{diffs}=161.896:1

Now I know all those numbers look cool, or have glazed your eyes over like a doughnut depending on how your clock ticks, but lets put it into a different perspective. MPH!

Here are a list of speeds based on the following facts: 1. tire size=235/75/15 (28.80" diameter 29s) & 2. idle=650rpms.
17.177:1 = 3.3mph (1st gear + t-case high)
52.734:1 = 1.1mph (1st gear + t-case Revo)
104.178 = 0.5mph (1st gear + dual t-cases low)
161.896:1 = 0.3mph (1st gear + dual t-cases Revo)

Here are a list of speeds based on the following facts: 1. tire size=235/85/16 (31.73" diameter 32s) & 2. idle=650rpms.
17.177:1 = 3.5mph (1st gear + t-case high)
52.734:1 = 1.6mph (1st gear + t-case Revo)
104.178 = 0.6mph (1st gear + dual stock t-cases low)
161.896:1 = 0.4mph (1st gear + dual t-cases Revo)

My musings on momentum

While being in a lower range does make 1st gear much slower, the other four forward gears are still available to you for those...shall we say... less then technical sections of trail. Here are the ratios of those other four forward gears: 2nd 2.248, 3rd 1.404, 4th 1.000, 5th 0.809. Plug any one you like into the above equations in place of 1st 3.767 & go. For example, if you get the Revo gears for your stock t-case & you want to get a real momentum burst, 3rd gear + t-case Revo = damn near the same ratio as 1st gear + t-case high... problem solved without ever coming out of low & no extra wear on the clutch vs trying it in high range.

~psguardian

P.S. If you wanna get REALLY Froggy, swap out the diff 4.56:1 gears with 4.77s(rare) or 5.13s(unicorn)
 

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Discussion Starter · #7 ·
So the base line of a manual is 2.28
Base line low for an auto is. 2.66
And tera's is 3.07 in low range.....Crawl ratio....
I do have an automatic T case sitting here. I think I shall open it up and see if it's possible to swap ???
 

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bradzuzu said:
So the base line of a manual is 2.28
Base line low for an auto is. 2.66
And tera's is 3.07 in low range.....Crawl ratio....
I do have an automatic T case sitting here. I think I shall open it up and see if it's possible to swap ???
Yes
Yes
& Yes

If you do end up doing the swap & find out that it doesn't grenade your t-case be thorough with the pics & instructions.

~psguardian
 

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Discussion Starter · #9 ·
Lol I will !!!! Being as though mines a 2000 , are the ratio's the same between first and second gen ??? It would be worthless if my ratio was that low already...
I think .38 would make a difference...
Changing out an auto would only be .41......
It's not a bad in between and it's free lol :)
 

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I think the ratios stayed the same, but the internals did change a wee little bit. Goto indy4x website to see the split for manual & auto rigs. there is a year range for both. within the range I THINK that it might be possible.

~psguardian
 

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Discussion Starter · #11 ·
Thanks !!! 99 auto t case and my 2000 mua5 t case should be about a match if possible...
 

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Discussion Starter · #14 ·

I'm sorry I had trouble with my post resetting !!! (sigh!!!)
I will proceed as the pictures flow .... First off I removed the case bolts followed by the servo shifter assembly. It was attached via the shift rail, so I dug deeper and removed the little cover..
I used needle nose to remove the drive gear, in turn allowing the link shaft to drop and slip apart.
My thoughts on this would be to put the t case 4wd before doing the project. I think it would save pulling the gear!!! I knocked out the two roll pins that would free up the shift forks, followed by pulling the output flange nut and flange assembly. In a vehicle the snap ring would be very difficult to remove/install on the front output shaft. So flange is my choice ( eventually it has to be pulled anyway) !!! With a brass hamer I popped the shaft back/ rearward about a 1/4" , that allowed for removal of the center shaft. With the roll pin removed from the mainshaft shift fork it simply slides off hub and all. Then both main and intermediate shafts remove. From there a couple more pops on the front output shaft and it's free from the bearing and it slides off shift fork and all. Not pictured was a spring attached to that shift fork that I had to remove.
 

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Discussion Starter · #15 ·

Empty housing !!! Most likely I will have to use the back half of the case or pull the output shaft and swap but really no reason to it feels fine. I'm sure the gear cluster is a different tooth count to.
 

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Discussion Starter · #16 ·


I guess I Missed this picture of the open case... It shows the output shaft gear cluster I was referring to. other question is the speedo gear. My tires are 33's , I'm running 4:10 's
And my speedo drive in my amigo now was setup for 4:30's. So don't I need to keep that ratio donut will keep my speedo as close to accurate as possible ??
Hopefully tomorrow I'll have time to do the swap.
 

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Discussion Starter · #17 ·

This shaft won't be as simple to deal with in the mua5,since it's one piece.


After removing the snap ring, I mounted up the puller.


With the end support bearing removed it's time to pull the nut. It has a dimple lock safety set up.
I usually just unscrew it and it pops out !!!


So far so good !!!


For practice and fit I put the shaft back into the housing to confirm the pullers would work in the vehicle application to.


Hope I will have room enough under the vehicle.




It pulled off fairly easy. This is a make or break point !! I carefully fit the clamp puller between the hub and gear slowly tightening it ... Do it wrong and you can chip or snap off teeth.


This is more of an FYI .... On sincro hubs in the trans there are usualy three locking spring loaded (dogs) that lock into the sincro hub. You can see the notches in the hub itself , can only go on one way , well three ways...


After the hub is pulled the idler gear slides right off...


This is the bearing and bushing set up on the main shaft and the front D line output shaft.
If the bearing goes out (low oil/no oil) it takes put the bearing. In the trooper that I had's case it wobbled and always popped out of 4wheel drive. And the drive line would drag/spin and try to lock in the automatic hubs cruising 60mph down the freeway !!!
 

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Did you get the little BB off of the shaft (goes under that bushing IIRC)? Don't forget that...
 
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