Transmission Gearing vs Differential Gearing. How do each effect performance?
Sorry if this has already been posted somewhere else in the forums (I couldn't find it). I'm wondering what effect the different gearing in the transmission has as compared to the differential gearing. Come to think of it I don't think I've ever actually learned what the exact effect differential gearing has in the first place... (can I scream newbie any louder?)
Also, as I'm going to be doing a transmission change soon anyway, would it be a better idea to swap out my beat up old axels and possibly change the differential gearing at the same time rather than at a later date? It seems to make sense to me but then I've never done any drivetrain work before so I don't know how much of a pain it is.
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1998 3.8 Completely stock. Soon to come: T56 Tranny!
Sorry if this has already been posted somewhere else in the forums (I couldn't find it). I'm wondering what effect the different gearing in the transmission has as compared to the differential gearing. Come to think of it I don't think I've ever actually learned what the exact effect differential gearing has in the first place... (can I scream newbie any louder?)
Also, as I'm going to be doing a transmission change soon anyway, would it be a better idea to swap out my beat up old axels and possibly change the differential gearing at the same time rather than at a later date? It seems to make sense to me but then I've never done any drivetrain work before so I don't know how much of a pain it is.
what makes you think your axles are beat?
the tranny works like the front gearing on a multispeed bicycle. The rear differential gear works like the rear gear on your bike.
the front gears translate the torque from your legs into rotational motion using a crank. In a car the up/down push is created by timed explosions on the crank of the car.
so the effect of changing the rear gear is just like changing the rear gear on your bike. a numerically higher gear makes it easier to pedal at low speeds, while a lower gear makes it easier to maintain high speeds but harder to pedal at lower speeds.
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Woe to him who builds his palace by unrighteousness,his upper rooms by injustice,making his countrymen work for nothing...Does it make you a king to have more and more cedar?Did not your father have food and drink?He did what was right and just,so all went well with him. He defended the cause of the poor and needy,and so all went well...But your eyes and your heart are set only on dishonest gain,on shedding innocent blood and on oppression and extortion. Jer 22:13, 15-17
Swapping a six speed is just like adding another gear to the crank of your bicycle -it extends the range where you can comfortably pedal.
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Woe to him who builds his palace by unrighteousness,his upper rooms by injustice,making his countrymen work for nothing...Does it make you a king to have more and more cedar?Did not your father have food and drink?He did what was right and just,so all went well with him. He defended the cause of the poor and needy,and so all went well...But your eyes and your heart are set only on dishonest gain,on shedding innocent blood and on oppression and extortion. Jer 22:13, 15-17
Nothing specific actually. I'm not sure how quickly axles wear out. My car has 140k+ on it so it's more of an assumption, really. By the way, thanks for all the information. Nice to know I can ask any question and get an answer that I can easily understand.
If I'm not mistaken in translating the rest of your response then, a lower gearing would be slower off the line but probably give better gas mileage while cruising and a higher gearing would give better off the line performance while taking a hit to MPG during cruising?
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1998 3.8 Completely stock. Soon to come: T56 Tranny!
Nothing specific actually. I'm not sure how quickly axles wear out. My car has 140k+ on it so it's more of an assumption, really. By the way, thanks for all the information. Nice to know I can ask any question and get an answer that I can easily understand.
If I'm not mistaken in translating the rest of your response then, a lower gearing would be slower off the line but probably give better gas mileage while cruising and a higher gearing would give better off the line performance while taking a hit to MPG during cruising?
Axles never wear out -they'll snap but that from more power than you're likely to make for a while -or they'll bend in a wreck.
as for the rest -you are correct. you can increase city mpg with higher gearing, but most of your mpg losses are from idling.
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Woe to him who builds his palace by unrighteousness,his upper rooms by injustice,making his countrymen work for nothing...Does it make you a king to have more and more cedar?Did not your father have food and drink?He did what was right and just,so all went well with him. He defended the cause of the poor and needy,and so all went well...But your eyes and your heart are set only on dishonest gain,on shedding innocent blood and on oppression and extortion. Jer 22:13, 15-17
Technically the axles don't wear out...but check the area where the axle bearings ride for pitting or grooves. If you've got that, the axles are junk.
yup. axles dont wear out, but bearings do, and they pit up the axles. as for the rest of your gearing. you have it backwards. a lower gear (numerically higher) will have quicker off the line acceleration, but a lower top speed, because of the engines useable rev range. a higher gear (numerically lower) will be more sluggish off the line but have a higher top speed and easier on the engine. your car could be equipped with either 2.73:1, or 3.27:1, or i think 3.08:1. can you pick the lowest gear which will yeild quicker acceleration from my explaination? the numbers mean how many teeth the ring gear has (for example) 2.73 gears will have 2.73 times as many teeth as the pinion gear. also the driveshaft turns 2.73 times for each revolution of the axle.
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Sr. Master Ford nerd.
saludos caballeros del ovalo azul
Technically the axles don't wear out...but check the area where the axle bearings ride for pitting or grooves. If you've got that, the axles are junk.
I've been thinking about the question about axles. I suspect he's coming from a FWD vehicle where the CV joints on the axles fail often.
That doesn't happen with a Live Axle -The U-joints can fail, but the axle rarely does.
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Woe to him who builds his palace by unrighteousness,his upper rooms by injustice,making his countrymen work for nothing...Does it make you a king to have more and more cedar?Did not your father have food and drink?He did what was right and just,so all went well with him. He defended the cause of the poor and needy,and so all went well...But your eyes and your heart are set only on dishonest gain,on shedding innocent blood and on oppression and extortion. Jer 22:13, 15-17
Thanks for all the great advice everyone. I appreciate it.
Oh, I forgot, you're probably going to need a reverse solenoid for the t-56. Look up Hyland Motorsports or D&D motorsports and you can just get the whole kit (if you haven't already).
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Woe to him who builds his palace by unrighteousness,his upper rooms by injustice,making his countrymen work for nothing...Does it make you a king to have more and more cedar?Did not your father have food and drink?He did what was right and just,so all went well with him. He defended the cause of the poor and needy,and so all went well...But your eyes and your heart are set only on dishonest gain,on shedding innocent blood and on oppression and extortion. Jer 22:13, 15-17
Transmission Gearing vs Differential Gearing. How do each effect performance? 
