Tranny Help
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Tranny Help
i have an 85 F150 4x4 it has the stock 3 speed tranny i need it to drive to MD and thought maybe a 4 speed would be better for interstate it has the 300 in6 any help would be appriciated...I Tried to research myself but not the best computer wiz
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From: Casa Grande
Is it a 3 speed auto, like the C6, or a manual 3 speed? If it's the manual 3sp I'd skip over the SROD 4sp and do a M5OD 5 speed, they should be about the same price at the junkyard. With that said, the SROD 4sp overdrive would be a straight swap, but you might have to do a hydraulic clutch if you don't have one. The M5OD would also be an easy swap but it requires you pull the bell housing as it has an integrated bell housing. You might also need a drive shaft depending on the transmission length. As for the auto trans, an AOD should bolt up with not to much problem. Any overdrive transmission should help with fuel mileage, plus keeping your speed around 60mph or so will to.
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From: Virginia
I show two three speeds being offered in 85, a manual and a c6 auto.
Changing to a regular manual 4 speed from a 3 speed will gain you nothing, they both have a final ratio of 1 to 1 in their highest gear. There was a overdrive 4 speed, but it's not known to hold up very well, but could be an option if you happen to find a good one.
If you have a c6 auto, changing to a 4 speed without overdrive might gain you 1 to 2 mpg at the most. Both of these trannies still have a 1 to 1 final ratio, all you would be getting rid of is some torque converter slip.
If you want the most for your efforts, swap to a AOD or a 5 speed tranny. I gained 3 mpg when I went from a c6 auto to a zf 5 speed in my truck.
Changing to a regular manual 4 speed from a 3 speed will gain you nothing, they both have a final ratio of 1 to 1 in their highest gear. There was a overdrive 4 speed, but it's not known to hold up very well, but could be an option if you happen to find a good one.
If you have a c6 auto, changing to a 4 speed without overdrive might gain you 1 to 2 mpg at the most. Both of these trannies still have a 1 to 1 final ratio, all you would be getting rid of is some torque converter slip.
If you want the most for your efforts, swap to a AOD or a 5 speed tranny. I gained 3 mpg when I went from a c6 auto to a zf 5 speed in my truck.
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From: Casa Grande
If you have an auto you might want to go with the AOD. It's a 4 speed overdrive transmission and should be a bolt in. Probably need a different shifter of some kind.
The M5OD or ZF5 will bolt up to your 300 as long as you get one from a small block Ford. They are both 5 speed manuals but the ZF is a better trans with a granny 1st gear. But you will need a pedal assembly for a hydraulic clutch, clutch master and slave cylinders, flywheel, clutch and maybe a cross member and drive shaft. And it would be a lot of work.
Plus, which ever transmission you get, you have to find a transmission for a 4x4 and maybe driveshafts to match.
You might want to give thought to just how much it's going to save you in fuel as compared to what it will cost. Figure out what it would cost at the MPG's you currently get, then figure out what it would cost if you got 2-3 mpg better. Being a 3 speed 4X4 I think you would have a C6 and that's a stronger trans than the AOD.
The M5OD or ZF5 will bolt up to your 300 as long as you get one from a small block Ford. They are both 5 speed manuals but the ZF is a better trans with a granny 1st gear. But you will need a pedal assembly for a hydraulic clutch, clutch master and slave cylinders, flywheel, clutch and maybe a cross member and drive shaft. And it would be a lot of work.
Plus, which ever transmission you get, you have to find a transmission for a 4x4 and maybe driveshafts to match.
You might want to give thought to just how much it's going to save you in fuel as compared to what it will cost. Figure out what it would cost at the MPG's you currently get, then figure out what it would cost if you got 2-3 mpg better. Being a 3 speed 4X4 I think you would have a C6 and that's a stronger trans than the AOD.
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my biggest concern is if it would hurt my truck runnin 80 up the highway with just the 3 speed
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Laughing Gas
Joined: Nov 2010
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From: Johns Creek GA
I have a 300/C6 combo as well, with a 2.75 rear end. 65 mph is about as fast as I'm comfortable driving it on the highway; the 300 simply isn't a high RPM engine. I've pushed it to 70 before, but that old engine was working hard at that point.
If you want to drive 80 safely you'll almost certainly have to do the tranny swap, and maybe think about your gearing as well. Or...you could do as I do, and simply enjoy the slower ride. I drive 80+ in my Infiniti all the time, one of the things I like about my truck is that I don't have to worry about speeding tickets.
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From: Dallas, GA
Like said before....don't matter what speed you have, they're all 1:1 ratio in top gear. The only way out of that is to put either an auto or manual overdrive in it.
You also said what would be quick, easy and cheap. Converting to an OD, will be none of those...especially the manual from an auto.
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From: Northeast, OK
The answer to that is a big yes. I can't imagine you having much higher gearing than 3.50 given the 4x4, and running 80 with that ratio and a C6 is going to be spinning the six very rapidly. It won't like it in a number of ways.
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