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Discussion Starter #1
i was wondering if you can just pop off the plate and pull out the ring and pinion and drop in a new one without carrier and seals.....cuz my diff isnt leaking but i cant stand those highway 3.08 gears anymore.... im pretty sure its a ford stock locker cuz both tires spin pretty good in rain or on dirt, but i cant get even a chirp or bark on cement so its kindof hard to look at burnout marks. :D but anyway is it possible, and if so is it worth keeping the old ford posy or should i by a good one from jegs or sumthing.
 

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No, you are gonna have to pull the whole pumpkin.
 

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Discussion Starter #5
well i know im gonna have to drop it out, i just want to know if i have to replace anything but the ring and pinion.... but im sure im gonna have to replace other stuff anyway.... im pretty sure one of my clutches is burned up.... it did some funny stuff a couple of days ago and now its like driving a one wheel wonder.... still cant spin them off the line but if im turning to the right it will burn like hell, but the left nothin....
 

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The computer will only be able to effectively compensate shift points for two steps up in gear without a tune. So a 3.55 is as tall as you'll want to go if a tune is not in the near future.

-Miller
 

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Discussion Starter #7
really?

well hell i didnt know that.... i think im gonna gut my tranny anyway cuz its at 124000 miles and never been rebuilt..... and its starting to shift weird and get a little laggy. overdrive still working fine though. :tongue: already tried fluid/filter change, but that didnt make a difference. but untill then i guess i will go with 3.55... thanks allot... i might have made a little mistake there. :D
 

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The computer will only be able to effectively compensate shift points for two steps up in gear without a tune. So a 3.55 is as tall as you'll want to go if a tune is not in the near future.

-Miller
bringing this back up. sue me :tongue:

will the 89-93 mn12s require a tune with more than two steps up in gearing, as well?
 

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bringing this back up. sue me :tongue:

will the 89-93 mn12s require a tune with more than two steps up in gearing, as well?
I am not an expert in this area but I do not believe so since the transmission is not electronically controlled.

-Miller
 

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The computer will only be able to effectively compensate shift points for two steps up in gear without a tune. So a 3.55 is as tall as you'll want to go if a tune is not in the near future.

-Miller
Yeah when I went with 3.55s on stock tune my speed limiter kicked in at 94 instead of 102 or whatever it was....been a long time since I hit stock mn12 speed limiter.
After I got chipped, i went with 3.73tl..awesome. And man 3.08 to 3.55 makes a big difference in acceleration. 3.55 to 3.73 wasn't as big of a jump.
-Rob
 

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Cant wait to replace my 3.08 its sooooo slow off the line but i love it once it gets going
 

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i have 2.73's haha, whats the highest i can go up for numbers one my gears? 3.08?
 

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Unless you switched the gears yourself, you need to switch the numbers around, change 2.73 to 3.27, which is what they all came with in 1997 as far as I know.

Al
 

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wtf?

who dug this up
 

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Just to clarify, a j-mod can take care of the gear change issues if you aren't planning on a tune. The issue is because the computer has it pre-programmed how long it takes to fill the accumulator and also how quickly the revs can climb. When you switch gears, you make the car accelerate faster, but it still takes the same amount of time for the accumulator to fill, so you could end up hitting the rev limiter. However if you make the accumulator fill faster by doing the j-mod and enlarging that hole, that will compensate for the car accelerating faster, and bring the shift points back down below the rev limiter. You can also see this because when you do a j-mod on a stock car, the shift points will actually drop a bit.

For the AOD cars, the shift points on that are controlled by the governor, which is on the output shaft of the trans. Changing rear end gears does not change the gear ratios inside the trans, so shift rpms should not be affected.
 

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Yeah when I went with 3.55s on stock tune my speed limiter kicked in at 94 instead of 102 or whatever it was....been a long time since I hit stock mn12 speed limiter.
After I got chipped, i went with 3.73tl..awesome. And man 3.08 to 3.55 makes a big difference in acceleration. 3.55 to 3.73 wasn't as big of a jump.
-Rob
Looking to put 3.55's on my '95 T-bird as well. Is there a lot of wear on the tranny when this is done? The tranny is stock, no mods to it.
 

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Looking to put 3.55's on my '95 T-bird as well. Is there a lot of wear on the tranny when this is done? The tranny is stock, no mods to it.
You will be running at higher RPM's so there will be more wear on the entire drivetrain. However... putting lower gears has the same effect as if you removed weight from the car so there is less wear on the drivetrain. I don't know if the two cancel each other out or if one aspect is more than the other. I guess it would depend on your driving habits.
 

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In my experience, putting gears in the back always resulted in less stress on the tranny. I've have a lot more problems with transmissions ranging from a broken case to burned up pumps & clutches with only 2.73 or 3.08 gears. I've never cooked a tranny with better gears in the rear. Of course, I've owned a lot more stock-geared cars than low-geared, so that may have skewed my results. Also, adding a shift-kit (or j-mod on these) makes life a lot easier on transmissions and if my vehicle had gears, it usually had a shift kit too!
 
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