no power in 3rd
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no power in 3rd
guys the truck has decent power in 1 and 2nd but once you hit 3rd its just nothing.
we done put a hotter coil and wires.and put a slighty bigger cam in.
but 3rd has nothing..
its a 4.9 300 6 with a 3spd tranny
we done put a hotter coil and wires.and put a slighty bigger cam in.
but 3rd has nothing..
its a 4.9 300 6 with a 3spd tranny
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Joined: Jan 2001
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From: Virginia
I am going to guess you have the 2.75 rearend. And you are hopping up the engine correct? Each time you do something to the engine, you are raising the rpm were it makes power. If I am right, your engine is barely turning when you hit 3rd, and the parts you have added are making it worse.
If I am on the right track, you need to change the rearend out. Something like a 3.50 to 1 would help it.
If I am on the right track, you need to change the rearend out. Something like a 3.50 to 1 would help it.
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I am going to guess you have the 2.75 rearend. And you are hopping up the engine correct? Each time you do something to the engine, you are raising the rpm were it makes power. If I am right, your engine is barely turning when you hit 3rd, and the parts you have added are making it worse.
If I am on the right track, you need to change the rearend out. Something like a 3.50 to 1 would help it.
If I am on the right track, you need to change the rearend out. Something like a 3.50 to 1 would help it.
we have a m5r2 tranny for it. but dont know if its going to make it worse or better.
pedant
Joined: Jan 2008
Posts: 23,576
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From: EXTREME southwest CT
Finding a rear end that allows you to use 5th as a cruising gear will keep your fuel mileage and let you accelerate through the gearbox.
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From: Virginia
You still need to remember the general rule of thumb though. If you are going to make a race horse out of this engine, you will need to rev it up. If you plan on doing anymore to this engine, you might need to go even higher in the numbers of the rearend with the overdrive tranny. But higher than 3.50 is going to be hard to find. 3.50 was a very common rearend, especially in the 4x4's.
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ah so it would have made it worst. well glad i ask first.
so putting a 3.50 rearend and the m5r2 tranny would make it better?
all im looking for is to be able to drive it without slipping the clutch like crazy. and have decent power through out the gears.
so putting a 3.50 rearend and the m5r2 tranny would make it better?
all im looking for is to be able to drive it without slipping the clutch like crazy. and have decent power through out the gears.
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pedant
Joined: Jan 2008
Posts: 23,576
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From: EXTREME southwest CT
It wouldn't "make it worse"
It wouldn't change a thing, except make it easier to row through the first four gears of the five speed.
Fifth would be worse than your current third gear.
Forth would be the same as the third you have now.
If you want more acceleration, change the rear end.
But realize your truck will be wound up on the highway.
Adding an overdrive 5th gear will help with (or eliminate) that consequence.
Also note that you will have to replace the speedometer driven gear to compensate if you choose to change the final drive ratio.
It wouldn't change a thing, except make it easier to row through the first four gears of the five speed.
Fifth would be worse than your current third gear.
Forth would be the same as the third you have now.
If you want more acceleration, change the rear end.
But realize your truck will be wound up on the highway.
Adding an overdrive 5th gear will help with (or eliminate) that consequence.
Also note that you will have to replace the speedometer driven gear to compensate if you choose to change the final drive ratio.
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Moderator
Joined: Jan 2001
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From: Virginia
Do it, you won't regret it. Do the rearend first, that's most important. You can then decide to do the tranny or not.
Lead Driver
Joined: Jul 2009
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From: Sheffield, AL
My son's 1984 F150 with 4.9L originally was equipped with 4 speed manual OD transmission and 2.47 rear gears. It did return excellent gas mileage on the highway, but was a D-O-G when it came to acceleration! It was no fun. It idled @ 8 mph, could go 40 mph in 1st and when a slight incline could be seen ahead while driving @ 60-65 mph, you had better shift down to 3rd.
The rear gears were swapped for a 3.55 unit and the truck was much easier and more fun to drive. It did lose 2-3 mpg on the highway. The OD ratio basically equaled what 3rd gear was prior to the differential change.
The speedometer [before correcting] indicated 79 mph for a true 55!!!!!
The rear gears were swapped for a 3.55 unit and the truck was much easier and more fun to drive. It did lose 2-3 mpg on the highway. The OD ratio basically equaled what 3rd gear was prior to the differential change.
The speedometer [before correcting] indicated 79 mph for a true 55!!!!!
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Senior User
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My son's 1984 F150 with 4.9L originally was equipped with 4 speed manual OD transmission and 2.47 rear gears. It did return excellent gas mileage on the highway, but was a D-O-G when it came to acceleration! It was no fun. It idled @ 8 mph, could go 40 mph in 1st and when a slight incline could be seen ahead while driving @ 60-65 mph, you had better shift down to 3rd.
The rear gears were swapped for a 3.55 unit and the truck was much easier and more fun to drive. It did lose 2-3 mpg on the highway. The OD ratio basically equaled what 3rd gear was prior to the differential change.
The speedometer [before correcting] indicated 79 mph for a true 55!!!!!
The rear gears were swapped for a 3.55 unit and the truck was much easier and more fun to drive. It did lose 2-3 mpg on the highway. The OD ratio basically equaled what 3rd gear was prior to the differential change.
The speedometer [before correcting] indicated 79 mph for a true 55!!!!!
though i have to say the work we have done to the motor has help in just idleing along.before when we came up our drive way you would have to hit it at speed before. now you can almost just idle up it.
but when you want to take off from a dead stop you have to slip the clutch like crazy to get it going
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