7.5 vs 8.8

[StimmyRanger]

So I don't know much about diffs. But my questions is:

What is the difference between a 7.5 with 4.10s and a 8.8 with 4.10s. I plan to upgrade to the 8.8 because they are stronger but will I notice any extra torque or anything.

 

[RonD]

In Rangers they are the same, neither is stronger
Both are
28 spline
1.21 inch diameter axle shaft
2.80 inch tube diameter
2,750lbs load capacity

If push came to shove I would put in the 8.8" over the 7.5" but wouldn't swap out a working 7.5"

The Explorer 8.8" was stronger
31 spline
1.32 axle shaft
3,200 load capacity
But have to cut and weld to use in a Ranger

No, no changes in power unless you change ratios and it just change WHEN the power comes not the power itself
i.e. 4.10 will give faster acceleration but lower top speed
3.45 will give higher top speed but slower acceleration

 

[dmb2613]

nope on the torque but you will have a bit larger brakes

 

[StimmyRanger]

Hmmmm I was telling a few people that I am needing to upgrade me gears to a 4.83 cause I put 33's and everyone said the 7.5 will get destroyed and I should get a 8.8 before doing so

 

[RonD]

With 33" tires you could twist the axle shafts on either, Explorer 8.8" might be worth the effort, and you could even go for rear disc brakes

 

[19Walt93]

How much power do you have and what will you use it for? I suspect you'll find 8.8 parts more plentiful and less expensive because it's a more popular rear end. Lower(higher numerical) gears than 4.10 will be easier to find for the 8.8. The 8.8 is a little heavier so if you were building a high performance cornering vehicle the unsprung weight would be a consideration.

 

[StimmyRanger]

The vehicle will be for pleasure and some home depot runs, nothing big. Only issue after putting the bigger tires is I have no power on the freeway, around town is still good. I was told by someone on here that did the math to get 4.83 or 5.13 to get that power back. There's a mobile gear guy in my area who said it would be $850 parts and labor for 4.83s on the 7.5.

 

[Uncle Gump]

Maybe I missed it...

Is this a 2 wheel drive?

 

[pjtoledo]

nope on the torque but you will have a bit larger brakes

the 7.5 axles came with either the 9" or 10" rear drum brakes.
it depended on the vehicles configuration, my 2000 4wd has a 7.5 and came with 10".
a 7.5 axle with 9" can be upgraded to 10" by swapping the backing plates.
the 7.5 has an extra 1/2" ground clearance assuming same wheels/tires.


edit:
I messed the part about 33" tires. they would push me in the direction of an 8.8.
what engine & gears do you have now?

 

[StimmyRanger]

2.5 2wd

 

[bobbywalter]

8.8 is much stronger then a 7.5.


Axle shafts are one issue...case deflection causing spider destruction is a whole different thing.

With power ... It matters. No power ... No matter


If your staying 4 whizzer. At least...488 gears. But 513 is better if you plan to keep 33 in tires.

At 513...the ring and pinion cross section will be better with a 8.8.

 

[scotts90ranger]

Didn't they stop making 5.13's for the 7.5? I haven't looked in a long time though... with a 2.5L I'd go 5.13's, that puts the engine speed in a good place, 3000rpm in 5th is around 72mph so not horrible for cruising, similar to 4.10's and 27" tires...

 

[sgtsandman]

With the 2.5 Lima, axle strength won't be an issue. Gear ratio availability is going to be better with the 8.8 over the 7.5. The engine, while reliable is a bit of a dog. I would recommend looking at the gears vs tires chart in the tech library to help decide where you want to be in the power range. From personal experience, 4.10 was a good match for the 27" tires on my 1998 with the 2.5 engine in it. I believe that put it in the best power for towing and hauling section of the chart. Right at the lower edge. Now, I live in the Appalachia Mountain chain with a lot of hills and valleys. If you live in a fairly flat area, you might be ok with a 4.88 vs a 5.13. You will have to be the judge on that since I have no idea what the terrain is like where you live and where you normally drive.

The other side of the equation is fuel economy. If your truck is set up like mine was from the factory with a tall, highway gear (3.45:1), switching to the 4.10 was a zero sum gain. I was burning more fuel than I should have trying to get up to speed and maintaining it with the factory gears that switching to the 4.10:1 gears still gave me about 21-22 mpg instead of the stated 27 or 28 it was supposed to get. If you have 3.73:1 gears in the truck, the swap might net you an mpg drop but you have already swapped tires where I stuck with the stock size. So, you might not see a difference or your mileage might get better.

 

[scotts90ranger]

Yeah, that. I'd still probably go with 5.13's though, I haven't been south of LA myself I don't think but if you drive freeway a lot 4.88's might be better but not by much for fuel economy... maybe 1mpg if I had to guess...