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Discussion Starter #1
So right now I've got the stock 3.27 gears. Well, basically everything on the car is stock.

I have been toying with the idea of having 3.73 gears put in, however I'm concerned that it will cause a domino effect on the mods I'm going to have to do.

Straight up, I know swapping in 3.73 gears will mean that I'll need a new speedo gear for the tranny. And I don't need to do the force lube mod on the tailshaft. BUT....

How does going to 3.73 gears with everything else stock affect the gear shifting?

It's not clear to me from the reading I've done here whether or not I'll need to get a custom tune. I don't really want more power, I just want a little better off-the-line acceleration. Gears will give me that.

My tranny shifts perfectly and I don't want to mess anything up by putting in gears. I'm actually leaning toward not installing the JMOD. But now I'm thinking if I put the 3.73 gears in, I'll have to do the JMod, then I'll have to buy a tune, then might have to buy a converter, then I'll want to install an aluminum Mark VIII driveshaft, etc. So this will get costly in a hurry. I just want to keep things simple.
 

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It won't have any effect on the feel of the shifts, but you may tag the rev limiter on WOT shifts. The reason is that the computer knows how long it takes the trans to shift, and how quickly the car accelerates in stock form, so it knows how long in advance to command the shift. If you make the car accelerate quicker, now you could hit the rev limiter before the accumulator in the trans has filled with fluid and caused it to shift. To solve this, you can either give the computer new instructions on when to shift (with a tune) or make it so that the trans doesn't take as long to shift (with the Jmod). Basically you will likely need to do one or the other, but no need for both just to compensate for the gears. The MarkVIII driveshaft is nice, but not absolutely necessary unless you regularly cruise at triple digit speeds. The converter will definitely help, and you would likely need a tune for that, but you would still see a benefit from the 3.73s even without touching anything else. If it were my car, I would do the 3.73s and a Jmod now, then save up to do the converter and tune later. If at any point in the interim you get a hold of a MarkVIII driveshaft, that is easy enoug to swap out, or do it at the same time as the converter since you would have to drop the trans for that anyway.
 

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Unless that 96 Tranny has been ran thru & the sorry Hard Parts it came with have all been upgraded (including JMOD'ing the VB) it's going to go from 'shifting perfectly" to pure scrap iron any day now - So IMO I'd stand by for that day then bite the bullet on your whole enchilada - Squaring away my 96 Tranny & new TC was about $2K - You may just want to keep an eye out for a low mileage newer 4r70w.
 

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Discussion Starter #4
My tranny only has 80K miles on it, driven by an old man since new. Does that make a difference? Based on what I've read so far I should probably do the jmod first, make sure it's OK, then do the gears.
 

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My tranny only has 80K miles on it, driven by an old man since new. Does that make a difference? Based on what I've read so far I should probably do the jmod first, make sure it's OK, then do the gears.
That sounds like a good plan. If you aren't having any transmission issues now, I wouldn't worry about it. With stock power levels and a Jmod, your 96 trans could easily have another 80K in it.
 

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Discussion Starter #6
Oh, plus the original owner had the tranny fluid changed (& filter) twice in the 80K.
 

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I went from 3:27 to 3:73 in my stock 95 bird. I also did the 93 Mark VIII driveshaft and the forced lube. I was worried about hitting the rev limiter on WOT but it doesn't. It will shift at WOT around 4800 rpm. Under normal acceleration it does shift sooner than with the 3:27's. But, I'm going to be doing all the stuff you said you didn't want to right away, Jmod, torque converter, tune... Oh, and my trans only had 85,000 on it when I swapped gears. So far, I've put 8000 hard miles on it and it's been doing great!

Mike
 

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My tranny only has 80K miles on it, driven by an old man since new. Does that make a difference? Based on what I've read so far I should probably do the jmod first, make sure it's OK, then do the gears.
You'd want to make sure you have the upgraded 1-2 Accumulator & optimize it's Spring Colors - & definitely delete 2-3 Accumulator Springs while you have VB down for JMOD - A few other tweeks & MAYBE it''ll last 120-150K miles.
 

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I wouldn't go throwing a maximum on the life of anything on any car. There is an average time where a trans will need to be replaced, but every engine and every trans in every car is treated differently. There are just far too many factors and variables to put a number on it.
 

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Im about to do jmod,gears,3800 converter, 93 viii ds on my 97 tranny that has 125,000miles on it, i only had it for a year with no shifting issues or noises of any kind, fluid isnt discolored either. Would it be stupid put all of that on that old of a tranny? I really dont have the money to rebuild one.
 

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Im about to do jmod,gears,3800 converter, 93 viii ds on my 97 tranny that has 125,000miles on it, i only had it for a year with no shifting issues or noises of any kind, fluid isnt discolored either. Would it be stupid put all of that on that old of a tranny? I really dont have the money to rebuild one.
IMO yes it would be stupid not to rebuild Tranny while doing all those other Mods.
 

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Whats the average cost of a tranny rebuild?? If i didnt rebuild it and the tranny shell out what what happen? or would it effect the tq, jmod ect.
 

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Whats the average cost of a tranny rebuild?? If i didnt rebuild it and the tranny shell out what what happen? or would it effect the tq, jmod ect.
As you already have a TC I say about $1500 to do it yourself including a new Cooler, Fluid, upgraded Hard Parts, all new Electrics... the WORKS - I would'nt jeopardize a good TC with a Tranny that could blow any day... NO MATTER do all that ripout & install work TWICE~!
 
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