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1987 - 1996 F150 & Larger F-Series Trucks 1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks

diff. gear swap?

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Old Jun 10, 2010 | 10:21 AM
  #16  
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Originally Posted by andym
Not reverse cut. Reverse spiral.



I don't think you'd want 4.88 gears with a 300 and a T-18.

At 60 MPH that would put you at 2800. At 70 you are running 3300.

Those numbers are too high. Transmission DOES make a difference.
Reverse cut, reverse spiral, who cares what its called, its a high pinion axle that's what matters.


And yes I would want 4.88s with 35s. I ran 35 with 5.13s with a 351M and a C6 for a couple years and LOVED IT!!!
 
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Old Jun 10, 2010 | 10:24 AM
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Originally Posted by hav24wheel
And yes I would want 4.88s with 35s. I ran 35 with 5.13s with a 351M and a C6 for a couple years and LOVED IT!!!
What kind of gas mileage did you get?
 
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Old Jun 10, 2010 | 10:26 AM
  #18  
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Ooops imatard
 
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Old Jun 10, 2010 | 10:27 AM
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Close to the same as I have gotten with all of my V8s......... 10mpg or so. Believe it or not, it got better milage in town than on the hwy though.
 
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Old Jun 10, 2010 | 10:29 AM
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I do believe that actually.
 
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Old Jun 10, 2010 | 10:33 AM
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It was a quick sonoabitch that's for sure. Plus it was my DD at the time. But now I'm done with the hijack
 
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Old Jun 10, 2010 | 11:11 AM
  #22  
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well i went back to that junk yard that quoted me $200 and he said tat is for open diff. so he said posi.(ls or any other) $250 so i asked him how much for them to pull them and he said $500 so i just walked away. called another locall pick and pull and they said $59 for each diff. and carrier. so i went their found a 94 f150 4x4 offraod ed. read the axle code and i was happy it had h9b so has ls in both front and rear . tried getting the rear gears and couldnt get the c clip out and i cut my finger baddd. after getting finger fixed i tried again no success so i just said screw it. its 120$ each axle with $10 core each and 25/30min for them to pull the stuff so i am just having them pull it. i wont do a core exhange. i will keep my axles in case something happens. now where can i get a shim kit from cause one broke? i take it, that it is a shim it sits between the bearing and the axle housing.
 
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Old Jun 10, 2010 | 10:41 PM
  #23  
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Originally Posted by hav24wheel
I just did a quick scan on the. Thread, and didn't see anyone correct this. ALL TTB axles ARE a HIGH PINION axle. Therefore require "reverse cut" gears. .
Ok, I apologize I was wrong on this, guess I never paid enough attention to mine to even notice, too focused on what its going to look like with it gone lol.

Originally Posted by jerg_064
With 35" tires and 4.56 gears... In Overdrive at 60mph:

E4OD--1870rpms

M5OD--2101rpms

'93 specs---145hp@3400; 265lbs/ft@2000rpms

Is 2K rpms too much for highways speeds? Do y'all cruise at like 1500 with that I6?
Originally Posted by jerg_064
(RPM*Tire inches)/(Rear gear*tranny gear*336)=MPH.......Any good at algebra, you can solve for anyone of them.

With 35" tires, a 3.48 rear gear would put you at the same ratio and driving rpms in your drive gear (1:1)...

So yea, a 3.55 would keep it the same for you. About 60mph @2000rpms in Drive (NOT OD if you have it). If you have overdrive, I think it's crazy to keep that tall of gears, but if your happy it's your truck.

Your not gonna lose 3-5mpg with 4.11s, that's rediculous.
Using a gear/tire/RPM ratio calculator is going to give you rough numbers, but its not going to be completely correct. Yes it does depend on the final drive ratio of the trans, but there are going to be variations in real world testing. Another thing, you have to remember the OP is driving a 4.9L I-6, not like our V8s. I6s make the most of their power (steepest part of the HP/TQ curves, not the peaks) down low, and if you're wanting fuel economy, you don't want to be at the peak anyways.

As far as a shim kit, you should be able to get some out of any carrier bearing or R&P gear install kit.
 
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Old Jun 10, 2010 | 11:50 PM
  #24  
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If you have the actual tire height, the numbers are not rough. Gears and RPMs are what they are.

As far as the I6 pushing those tires, I've already taken Bill's word for it on the the gears and drive-ability.
 
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Old Jun 11, 2010 | 06:20 AM
  #25  
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Originally Posted by 6CylBill
It does with 35 inch tires, man. It's still a six banger and needs the torque multiplication to turn over those tall, heavy tires.



I run at 2,100 RPM at 60 mph. 31 inch tires, 4.11 gear. About 2,500 to go 65 / 70. I don't like those RPM's on the highway with the 300. The 300 does best around 1,500 on the highway.
I agree with that, I was saying that it didn't need as low of gears as the 5.0 would with those size tires. I was just trying to say that he wouldn't need really low gears.

I also agree that the 300 needs to stay below 2k on the highway.

So for your 300, if your going to keep 31s then stay with 3.55. If your going with 35s then go 4.10.
 
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Old Jun 11, 2010 | 08:09 AM
  #26  
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now how can i pull the front axle out? what i was thinking was unbolting the 2 boltls in the middle, the springs, take the steering crap off, and unbolting the 2 bars from the frame(not sure what they are called) so i dont have to fight with them on the axle. i stopped at the place to see how its coming and they said it wouldnt be anytime soon i would get them so im just going to go take them off myself so i can get them quicker. its just that if it would stop raining i would go get them.
 
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Old Jun 11, 2010 | 09:00 AM
  #27  
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You don't need the whole front axle you just need the pumpkin, so disconnect the driveshaft and then dismantle the drivers side hub and remove the axle shaft, then simply unbolt the pumpkin from the TTB arm and pull it out from under the truck. The inner portion of the passengers side drive axle is C-clipped into the diff, you could remove it or simply leave it attached if the U joint is good and install the whole assembly back into your truck in reverse order.
 
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Old Jun 11, 2010 | 01:57 PM
  #28  
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i got the rear out now. now someone was telling me that if i get used gears its like a camshaft that it forms to a certain differential and it is fitted for that diff.

well on my way to work on thursday i stopped and asked if they started pulling them yet they said no. the guy was telling me it might be a while so i had today off but it was supose to rain all day and storm so i thought i couldnt go at all today but thier was a break in the rain and i went out their and got started on taking it off. it had the swaybar on it which i wish i could have kept but i dont have the frame brackets for it then. the ground wasnt that wet., so i started takeing it apart. i could hear the thunder coming and i was like crap i wouldnt get it today. i got to just connecting the parking brake cables and the shocks. then it started to down pour so i just walked back to the building and i was soaked. got 2 helper springs also. i was thinking im that far i mise well go back and get it out. it calmed down a little with the rain but the part i was at was a little down hill so their was a little puddle under the truck and stream down the main isle. but i just kick and kicked till the top shock mounts fell off then it started to down pour again and im just soaked. but of course when i get toe bringing the axle up front it quits raining again. so i got the rear off now just the front.
 
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