swap last 2 gears in transmission?

termite289 · May 19, 2009

yes you heard me right, i want to take the transmission out, take it apart, put 5th gear where 4th gear is, and 4th gear where 5th gear is, then put it all back together.
i have been pondering this for about 3 weeks now, and thought id see if anyone had any suggestions as to where to get this done. or perhaps how much it would cost.

bluejaybee · May 19, 2009

Ugh...me tinks u beena setting fer too long!

None of my business but I'll ask anyways.

What you hope to accomplish by doing it?

Dakota · May 19, 2009

Now you have my curiosity up, why would you want to do this?

Maybe to fill up time between loads?

termite289 · May 19, 2009

when i first started driving, i knew a couple of crank head drivers. two of them had this minor surgery done to their trucks. the end result was not only a screwed up shift pattern, something else. the trucks had a whole new gear ratio when they got to the top end. a 13 speed tyranny, is nothing more than a 5 speed with accessories. each time you flip a button, you are still using the same 5 gears, only a different part of the accessory or back box in driver speak.
when they swapped the last 2 gears, their trucks would run much faster than a factory transmission, at the same rmp. because it changed the ratio on the last 2 gears, and put 5th, 12 and 13 against the dash, my thinking was that if i had 4th10th and 11th down where it was not supposed to be, then my truck could still run canada, as the computer shouldn't have to be told that the gears are different. so my 90 mph truck would turn into a 120+ mph truck, and could set the speed limiter for canada at 65, and everyone is happy.

termite289 · May 19, 2009

of course anyone who decides to attempt this should also take note, that the loss of pulling power because you have much higher gears is quite notable. not a good idea to try if you spend a lot of time on mountains.
currently im running about 1550 rpm at 70 mph. I am estimating that this would drop it to around 1200 rpm at 70 mph so you can see that this is at the very bottom of the power range. i almost never get loads out west, and live where the speed limit is 70. it is just a thought that has been swimming around in my mind for a few weeks. and i was wondering if there were any old timers left who knew about it, and where i could get it done.

bluejaybee · May 20, 2009

I assign this task to piper1. He can tell you what will work or won't.

It just looks to me that if you are right, the negatives would out weigh the good. I'd want to see it on paper or in person before I tried it. I fully understand what you are trying to do, I just don't have the knowledge to figure it out.

Refer Hauler · May 22, 2009

I have driven a truck or two with this setup in the days before the electronicaly controlled engine. It was not an uncommon setup especially with oil field trucks and bull racks out west.You could run well over a 100 mph but your right arm got a work out shifting in the mountains. Finding someone who knows exactly what to do, and if it would work with the computer managed engines of today would be my concern. Post this question on the OOIDA or a custom truck web site (largecarmag.com)you might just get an answer.

termite289 · May 23, 2009

may try that, but i think the need is kinda moot at this point.

greg334 · May 23, 2009

Well I heard of this in the 70's, don't remember the details but could not see how it is done without knowing exactly what transmission is being used.

But with that said - back in the day when things were cheap, especially labor, a lot of things were done - gears swapped, fourdoors made into convertibles and so on. It would have been easy back then to do this and it failed to replace the trans and other damaged parts of the truck without a high cost.

SO..... if you are so incline to take a chance, have the money, go for it. just removing the trans will be fun, then you have to figure out what gears are what and what happens if it messes the trans up, then what? Glad you have the money.

roadrocket · May 25, 2009

I think you should first look at swapping the rear end gear with a lower ratio first. This is cheaper and if you don't like it it's easy to go back to stock.
Fooling with the trans gearing just doesn't sound possible or if possible then a lot on money.

termite289 · May 26, 2009

y'all missed the whole point.
if i moved the gears in the trans, i could set the truck by the computer to run 65mph in high gear, so that it would be legal in canada. the cpp officials who are going to be checking it with their hand held computers are not going to be riding in the truck, they will be checking it at a dead stop. if the computer says it will run 65, then they have no choice but to believe the computer. so i don't get a ticket, and when i get down south, i can still run fast enough to keep my other customers satisfied.
the computer doesn't have to know i moved the gears, and i'm not going to volunteer the info if and when i do get checked.

guido4475 · May 26, 2009

I have an easier and cheaper solution:Just dont run Canada.

greg334 · May 26, 2009

Termite, My good insect.... the computer, ECM that it is called doesn't measure speed by RPMs it measures it by the sensor in the transmission - at the output shaft of the transmission. It is better to wait for an electronic solution before throwing money away...

termite289 · May 28, 2009

you can set the ecm to what ever you want, if you wish to set it to shift progressively, then you will not be able to get above 1200 rpm in 1st - 5th gear, then it gradually increases until you get to the last gear. you can set the ecm to run by speed, or rpm. and you can set the rpm in each gear differently. if you don't tell the ecm that you moved the gears, and tell it to un no faster than 65 in 13 gear, then when the shifter is in 13position, that's what you will get. however if you move the gears, when the shifter is in 13th position you will be in 11th gear, with 2 more to go.
and yea canada is probably out

P51bombay · May 28, 2009

I'm curious, if you can swap gear positions - can you take a 10spd overdrive and replace 10th with a direct (non OD) drive gear? I'm about 200rpm low and the only other option is to re gear the rear end which in some ways would be not so good as it would put the truck in 9th going down the road at 30mph which seems a bit ridiculous.

greg334 · May 28, 2009

termite289 said:
you can set the ecm to what ever you want, if you wish to set it to shift progressively, then you will not be able to get above 1200 rpm in 1st - 5th gear, then it gradually increases until you get to the last gear. you can set the ecm to run by speed, or rpm. and you can set the rpm in each gear differently. if you don't tell the ecm that you moved the gears, and tell it to un no faster than 65 in 13 gear, then when the shifter is in 13position, that's what you will get. however if you move the gears, when the shifter is in 13th position you will be in 11th gear, with 2 more to go.
and yea canada is probably out

Makes no sense... sorry dude.

Are you talking about an auto/ultra shift transmission?

termite289 · May 29, 2009

was talking about an Eaton/fuller 9 or 13 speed manual shift transmission. don't think it would work with an auto shift. and i have no clue about the 10 speed either.

greg334 · May 29, 2009

OK, Progressive shifting is not programmed with manuals, it is programed with computer controlled transmissions like auto/ultra shifts.

The swapping of the gears will not produce the results you want because the ECM picks up the speed signal at the end of the trans where the driveshaft is. The programming that is done to limit the rpms has to do with the governor of the engine, preventing damage to the engine itself while the speed limiter within the ecm is taken exclusivly from that sensor in the trans, it is what Ontario wants to see changed to 105 km. The ECM will see only the speed of the truck unless the speed limited is greater than the rpm cutoff point then it will use the rpm cutoff point to limit the speed of the engine - make sense?

Swapping gears may also effect the life of the trans, without going into detail of the manufacturing of gears, there is a reason for those gears being there.

I put the gear changing stuff in the category of cowboy trucker's BS.

So here is a secret, if you want to really want to mess with something to 'cheat' the system, change the correction value within the ECM to tell the ECM you have a different rear end, then you can set the ecm speed limiter to 62, and drive 70. BUT BE warned that doing so will screw up your speedomter and odometer, total mileage that is recorded in the ECM and if you have a MPG indicator on your truck, then is will screw that up too.