idiambulance
Registered User
Im trying to figure out what differential I have. What can I look at to determine which one I have? Im trying to change the differential fluid but im not sure which one I have.
What Differential I have
- Thread starter idiambulance
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Fredrickson
Full Access Member
Check out the tag in the driver's door.. bottom row of letters
Identify Your Ford Truck Axle From The Door Sticker - Blue Oval Trucks
Here's how to Identify Your Ford Truck Axle From The Door Sticker by looking up the axle code on your sticker listed on this page.
www.blueovaltrucks.com
idiambulance
Registered User
This is teh only sticker I have left on the drivers door. If it says it here I dont know where.Check out the tag in the driver's door.. bottom row of letters
Identify Your Ford Truck Axle From The Door Sticker - Blue Oval Trucks
Here's how to Identify Your Ford Truck Axle From The Door Sticker by looking up the axle code on your sticker listed on this page.www.blueovaltrucks.com
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Fredrickson
Full Access Member
Under AXLE is says 69 So you it appears you have
A Ford 10.25 rear end, rated for 8250 lbs with 3.25 gearing
A Ford 10.25 rear end, rated for 8250 lbs with 3.25 gearing
idiambulance
Registered User
Sorry Im learning here. Im trying to figure out how much fluid and what type I need to change my differential fluid. What use would those two numbers give me in the future?
chillman88
Full Access Member
All you need to know from those numbers for your current question is it's a Ford (sterling) 10.25 rear axle.
Buy a gallon and after you've drained it fill it until it starts coming out of the fill plug. Looks like no limited slip so no need for an additive.
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Buy a gallon and after you've drained it fill it until it starts coming out of the fill plug. Looks like no limited slip so no need for an additive.
idiambulance
Registered User
Thank you so much for your help. What a learning experience working on these is.
Scotty4
Full Access Member
Grab some permatex black rtv and clean that mating surface well. Have fun!
The_Josh_Bear
Full Access Member
Fredrickson
Full Access Member
The chart on blue oval mentions the 3.55 for 1991.
The sterling 10.25 (with no years listed) says 3.25.
I was curious..so did some checking..
https://www.globaldrivetrainsupply.com/rebuilt-ford-differential/ offers the 10.25 with 3.25 gears (bottom of page)
I have 4.11 so I am a bit envious of anything taller than that
The sterling 10.25 (with no years listed) says 3.25.
I was curious..so did some checking..
https://www.globaldrivetrainsupply.com/rebuilt-ford-differential/ offers the 10.25 with 3.25 gears (bottom of page)
I have 4.11 so I am a bit envious of anything taller than that
The_Josh_Bear
Full Access Member
Can you imagine how gutless an N/A Ambulance would be with 3.25 gears?! Ha! I moved to 3.55 from 4.10 and even with a good turbo setup the switch still gets me in an empty pickup. Good on the freeway and that's it.
idiambulance
Registered User
Im curious what you mean. Im not super fast but I have decent pickup and can get to speed. I do go up steep hills pretty slow but I figured that was just par for the course. What exactly are the pros and cons of a N/A engine with a 3.25 gears set.
Big Bart
Tow&Slow
Pro’s for 4.10 is better torque and pulling power. If towing this is the set up. Top end speed is limited but towing big loads at 70-80 is generally dangerous and in some states illegal.
Pro’s for 3.xx faster at mph more like 16-18mpg (vs 11-14) and higher cruising speeds. More like 75mph at 2,800rpm than my 65mph with a c6 and 4.10. Good for daily driver that only moves loads/tows occasionally.
My 2 cents.
Pro’s for 3.xx faster at mph more like 16-18mpg (vs 11-14) and higher cruising speeds. More like 75mph at 2,800rpm than my 65mph with a c6 and 4.10. Good for daily driver that only moves loads/tows occasionally.
My 2 cents.
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idiambulance
Registered User
Good to know. I wasnt planning on towing anything and if I did it wouldnt be very heavy at all.
Fredrickson
Full Access Member
To oversimplify, it is how many times the driveshaft needs to turn to rotate the rear wheels once.
The more turns it takes per rotation.. (say 4.10 turns to rotate the wheels once), generally means the more torque, (pulling power) you will have at lower speeds, but it also means the more engine rpms it takes to move down the road at a given speed.
So at highway speeds, your engine is spinning slower to maintain say.. 65mph, than someone with 4.10 gears. where the engine spins faster by comparison to maintain the same speed.
Once your C6 hits 3rd gear, your engine is spinning 79% as much as someone with 4:10 gears.. so better fuel economy, better top speed for you.. but it's an effort to get the truck's engine rpms into the sweet spot where it makes the most power.
After you build out the box, with the added weight, (particularly if you plan on having a water tank) you may find your speed gradually slowing down, or requiring you to put your foot into it, as you go up a loooong hill.. ever see a truck lane on the interstate?
Hope that helps..
The more turns it takes per rotation.. (say 4.10 turns to rotate the wheels once), generally means the more torque, (pulling power) you will have at lower speeds, but it also means the more engine rpms it takes to move down the road at a given speed.
So at highway speeds, your engine is spinning slower to maintain say.. 65mph, than someone with 4.10 gears. where the engine spins faster by comparison to maintain the same speed.
Once your C6 hits 3rd gear, your engine is spinning 79% as much as someone with 4:10 gears.. so better fuel economy, better top speed for you.. but it's an effort to get the truck's engine rpms into the sweet spot where it makes the most power.
After you build out the box, with the added weight, (particularly if you plan on having a water tank) you may find your speed gradually slowing down, or requiring you to put your foot into it, as you go up a loooong hill.. ever see a truck lane on the interstate?
Hope that helps..
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