hey i recently had the wise ass idea to run dual tranies in my truck just for craps and giggles the second basicaly being an over/underdrive unit ie regear it so second is 1:1 3rd some ratio oof overdrive 4th being even more overdrive and not forgeting 1st as an underdrive. i just need to know what the limitations are pretaining to regearing a tranie. why you ask i just want something different and i think it would be badass!

young bucks bring fresh ideas!!!!!

"young bucks bring fresh ideas sometimes they work sometimes they dont but all the same it was an idea it wasnt the first it wont be the last either!"

Y-Guy Young Buck:    A couple of things, if you're going

             inside the transmission to actually swap gears

            lots of $$ will be required.

            The early 4 wheel drive trucks had "divorced" transfer

            cases(short driveshaft from trans to the transfer case)

            That might be a way to do what you're looking for

             but you would have to find a way to put "yokes"

             on the units you would be using, plus driveshaft

            angles, plus total length of all might create problems..

                   Keep the idea's coming.

                                      Bill

                  Pray for our troops,especially today!

Bill

Pelham,Al

All that 2 3 speeds will get you is underdrive. To simplify things, let's assume that the gear ratios for both transmissions are 3:1 in 1st, 2:1 in 2nd, and 1:1 in 3rd. With the 2nd trans in 3rd, your ratios are 3:1, 2:1, and 1:1. With the 2nd trans in 2nd, your ratios are 6:1, 4:1, and 2:1. With the 2nd trans in 1st, your ratios are 9:1, 6:1, and 3:1. In this scenario, you actually only have 6 ratios as 6:1, 3:1, and 2:1 are possible with a couple combinations of the hypothetical transmissions.

If you were to use this setup with a tall rear ratio, like 3.00:1 or taller, you can achieve the same thing as overdrive, as compared to what you had.

My personal opinion is that it would be neat but for the price/time involved to get it to work as desired, simplify the idea and install a 6 speed.


Lawrenceville, GA

How about this for giggles.  First if you use two 3-speeds lined up in a row, you would never get to over drive.  But if you turned the second one around backwards and made a coupler for the two tail shafts to mate up and shorten and machine the second tranny input shaft to accept a drive shaft yoke, you could have a six speed with the sixth gear being over drive.

By only shifting the second tranny from 2nd to 3rd, you would have five gears to get to 1:1 and the sixth gear would be over drive.  When you shift the second tranny to 3rd, you would have direct.  When you shift to 2nd in the second tranny you would have an over drive effect.  (1st direct, 1st over, 2nd direct, 2nd over..........etc.

Nothing new here, it would be like having a 2-speed rearend............just using different pieces. 

Charlie Burns Laton, Ca (South of Fresno)



BurnsRacing981@gmail.com

Turning the second around would work. Using my hypothetical ratios, it will provide 7 unique ratios of 1:1, 2:1, 3:1, 1:2, 3:2, 1:3, 2:3. If you figure in 3:3 and 2:2, it's technically 9 speeds.

It will make for an interesting shift pattern and you'll have to be flying to make use of the 1:2 and 1:3 ratios.


Lawrenceville, GA

Charlie, how about fitting a gearbox to each side of the diff, cut the axle tubes, adapt trans input shaft to act as axle from diff center, then adapt trans output shaft to reconnect to wheel end of axle. Then you could sit in the back changing gears  and have 3  independent speeds fpr each axle, good for off road?? just kidding!

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

OR, you could put one wheel in reverse and the other in forward and drive in circles!! Like GM does most of the time!!!

Frank/Rebop

Bristol, In ( by Elkhart) 

Frank; OR put both in reverse and drive backwards  like GM does all of the time!

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

ok im being serious here like above mentioned what are the limitations to regearing a transmision? the second 4spd being regeared so first is underdrive second is 1:1 3rd od 4th another od that was what i was saying i thought i made that clear above! further mor if i was intending on having something someone else has already done id just throw a t56 in it!

p.s. even i know that two stock 4speeds coupled together is just basicaly gonna turn my truck into a 1/2 ton tractor!!!!

"young bucks bring fresh ideas sometimes they work sometimes they dont but all the same it was an idea it wasnt the first it wont be the last either!"

Interesting concept but where would you get the gears for "re-gearing the second four speed"? Not to mention how you would connect the two?? I think someone already mentioned a two speed rear axle. Or maybe looking into a Gear Vendors Under/Overdrive? I have one on my C-4 and with gear splitting gives me six speeds altho I don't usually use it like that. I use it as 1st to 1st OD for close ratio take off shift (just mash the button for second) and 3rd O/D for highway.

BOB