Gearing from 3:45's to 3:08's

ngzcaz · Oct 2, 2007

Anyone have any knowledge what the difference in gearing would be ? A
V6 enough to handle this tall a gearing ? Little if any hauling done by this truck.
What kind of speeedometer change is available, if any, in the cable going from the tranny to the dash ? Reason for the change is the addition of a L/S carrier in the rear end.
Anyone make this change ?

:3gears:

Hahnsb2 · Oct 2, 2007

I would NEVER do that with a v6 ESPECIALY with an A4LD even if it only sees the roads unloaded with small tires you're just begging to fry your tranny. Id be willing to bet your gas milage would suffer and overall it would be a dog. If anything Id go up to 3.73s...

Ranger44 · Oct 2, 2007

I think you might have gearing backwards.... a taller or lower gear is numerically higher. So if you want your engine to have more leverage over your tires, i'd put in some 3.73's or 4.10's... you'll actually end up getting better gas mileage and some get up.....

MAKG · Oct 2, 2007

If you're going through the expense of installing an LS carrier into your rear end correctly, just put your original gears on it. No messing with speedometer cables, no screwed up gearing (it really is backwards...). No new risks on the transmission. And so on.

If you're NOT going through that process, stop now before you break your truck. If the truck even moves, it will break almost immediately. Gearsets must remain together, especially with different gear ratios.

ngzcaz · Oct 2, 2007

I should have mentioned that this is the stock 5 speed manual trans which in 1st gear is plently low, however the succeeding gears get tall in a hurry. I dont want to lug the truck but I do a lot of interstate 80 driving in a year and thought it might work.
The L/S carrier is basically what I'm most concerned about. It was a real dog in the limited amount of snow it saw last year. Cant handle that again this year.
I was curious if anyone had actually made the change and with what results.

:bye:

Hahnsb2 · Oct 2, 2007

Ranger44 said:
I think you might have gearing backwards.... a taller or lower gear is numerically higher. So if you want your engine to have more leverage over your tires, i'd put in some 3.73's or 4.10's... you'll actually end up getting better gas mileage and some get up.....

No, you have your gears backwards. "Tall gears"= high gears (numericaly lower).

Trust me you don't want 3.08s, I wouldnt go any taller than what you have now. I made the assumption that you had an A4LD since thats what's in you profile info, you're also gonna be sliping your clutch more than you want. Running your engine on the highway at 3000+RPM wont hurt it.

ngzcaz · Oct 3, 2007

3200 rps is about the number on my monthy 800 miles trips. I knew the automatics were around 3:08's and mine 3: 45's are about the highest ( yes I know the difference between the numbers, the 60's taught me to run 4:11's or 4:56's at the strip ) that Ford made for a manual trans. I probably wpould find myself shifting a bit more than I'd like so I'll probably stick with the 3:45's.
Shame no one posted they made this change, I'd have liked to know first hand what impressions they had.. Thanks for the replies.

:icon_cheers:

Hahnsb2 · Oct 3, 2007

Well, I just did some calculations. I put 31" tires on my rig, which effectivly made my gear ratio a bit higher (numericaly lower) than 3.08 (with 3.45 gears). I couldnt hold 5th at ANY speed with my 2.9 unless traveling downhill and ended up having to use 4th gear which brought my RPMs back up to where 5th used to be before changing tire sizes, Im now running 4.10s. Im just saying if you go to 3.08s you probably wont be able to hold 5th and have to use 4th anyways which makes changing gears a waste.

Ranger44 · Oct 3, 2007

"No, you have your gears backwards. "Tall gears"= high gears (numericaly lower)."

I corrected taller by saying lower. I agreed with you by saying that he would be happier with a much lower gear...both with gas mileage and get up. Lower gears will help with the smaller engine.

AllanD · Oct 13, 2007

Actually you are more likely to shift LESS with numerically larger gears, because with 3.73's you wouldn't have to DOWNSHIFT as often for every little pimple of a hill.

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Gearing from 3:45's to 3:08's

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