475,000 mile F7 rear axle

[Paisano]

I have a 92' Ford Ranger XLT with 2.9 V6. It has the 7.5 inch limited slip rear axle with 4.10 gear ratio

I've monitored a humming noise from my rear differential for a long time. It kinda' sounds like those big off-road tires. I had bearings replaced in my rear axle assembly about 10 years ago.
But the rest of the rear end is original at 475,000 miles. I figure on taking it apart with a rebuild kit and extra parts that can be returned for a refund if not needed.

I understand the pre-load and proper meshing of the gears is critical. And this concerns me.

Honestly, I can't begin to ask questions on this subject unless I get a basic understanding of the F7 rear axle assembly. I need to learn on my own first. Any online guide or a book you guys can recommend ?
I tried searching this website and online.

 

[Dirtman]

I understand wanting to learn how to do the repairs but I offer this information first.

Properly rebuilding a rear axle is not just a matter of skill (it does require alot of skill) but it also requires special tools that can be quite expensive. There are special tools to set the proper pinion depth, special gauges needed for measuring several things, a press and separator plates, setup bearings etc. Buying all this stuff is expensive before you even buy the actual replacement parts which are also expensive. You would need a master overhaul kit, ring and pinion gear set, and the LS clutch rebuild kit.

At nearly half a million miles it's realistically cheaper, and easier to simply replace the entire axle assembly. Now you do have a somewhat rare axle (7.5 limited slip 4.10). But the 8.8 ranger axle is a direct replacement and 4.10 L/S is not that uncommon in those. If you dont really need the limited slip then they are even more common. You could pick up a good used junkyard axle with a fraction of the miles of what you have for a 10th of the cost of a full rebuild of your current axle. You may still need to put new brakes on it, some new seals, and even if you replaced the bearings you would still save a ton of money.

Now I'm not saying don't rebuild your axle, just pointing out less expensive alternatives.

However I know there was a good video series on youtube on rebuilding rears, as soon as I find it I'll post it for you. Also check the tech section here on the site, there's a ton of info on axles/gears in there.

Axle Tech - The Ranger Station

DISCLAIMER: Activities and vehicle modifications appearing or described at The Ranger Station and it’s pages may be potentially dangerous. We do not endorse any such activity for others or recommend it to any particular person – we simply describe … Continued

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[Paisano]

Hey Dirt,

You gave me something to think about here. Yes, the correct use of and cost of the special tools are concerns also. Even though I'll give it serious consideration, I'm not crazy about the idea of a used axle assembly. I might want to just buy a remanufactured 8.8 inch complete rear axle assembly from the auto parts store. I do all my own repairs. But I have no experience with differentials. I have rear drum brakes, I'll start looking at junkyard and reman complete assemblies.

But what 8.8 assembly is compatible with my make/model?

Is it a direct bolt-on with no modifications?

Should I match another make/model/year 8.8 to my truck?

 

[bobbywalter]

Flange issue will be main problem..... and not a hard one.


80 to 100 for a good used rear where I live and 40 in u bolts and oil. Shopping around for a unit with fresh brakes for the win.

 

[Dirtman]

Hey Dirt,

You gave me something to think about here. Yes, the correct use of and cost of the special tools are concerns also. Even though I'll give it serious consideration, I'm not crazy about the idea of a used axle assembly. I might want to just buy a remanufactured 8.8 inch complete rear axle assembly from the auto parts store. I do all my own repairs. But I have no experience with differentials. I have rear drum brakes, I'll start looking at junkyard and reman complete assemblies.

But what 8.8 assembly is compatible with my make/model?

Is it a direct bolt-on with no modifications?

Should I match another make/model/year 8.8 to my truck?

Any 8.8 or 7.5 from a ranger will be a direct bolt in for your 92 from I believe 86 all the way up to 2009, I may be wrong but I believe earlier than 86 we're a tad narrower? 2010 and 2011 also work but have disc brakes which is a great upgrade but requires some minor modifications such as different parking brake cables and brake lines. The one exception being if you have rear ABS you need to make sure you get one that has the provision for the sensor. If you don't have rear ABS you can still use an axle with the sensor you just obviously would leave it unplugged.

Explorer axles also work but are not bolt in replacements. The spring perches are upside down which requires cutting them off and welding them on the top.

I know getting a used axle seems sketchy but your talking about going from one with a zillion miles. Just check it out before you buy it, ask how many miles were on the truck it came from, check for metal in the fluid and that it actually has fluid. Feel the play in the pinion and axle shafts. There's no reason to fear using a used axle if you do your homework on it first. Tons of guys here who off-road hard use junkyard rears. And like I said you can still throw new bearings in it and still be waaaaaaaay under what it costs to do a complete overhaul on what you have now.

 

[Paisano]

Very interesting. Thanks Dirt and Bobby. I'll stay away from Ford Explorer.

From my reading, people seem to prefer the 8.8. Why is that? I heard it was considerably heavier.

Bobby said the flange issue will be a problem. Does he mean the drive shaft won't align with the rear axle companion flange at the correct angle and height?

 

[Dirtman]

People like the 8.8 because it's a tad stronger, and they are much more likely to have the limited slip option compared to the 7.5. the 8.8 is not much heavier than the 7.5, its practically the same size. It just has slightly larger ring and pinion gears. The axle shafts are the same between the two unless you get a 31 spline 8.8 but they are rare except in explorers.

There is no issue with the flange as far as alignment or driveshaft fitment in that respect. At the most all you have to do is change the flange on the driveshaft end. Both use the same u-joints and fit the same way, it's literally just a slightly different bolt pattern on the flange. But I'm pretty sure most of the 8.8 pinion flanges have bolt holes for both style driveshaft flanges anyway. I may be wrong on that but its still no big deal to solve.

 

[85_Ranger4x4]

Axle width changed for 1993.

Ford Ranger Rear Axles (1983-2011) - The Ranger Station

Rear Axles Used: Ford 7.5-Inch Axle: 1983-2011 Ford Ranger’s without a 4.0L V6 came with the Ford 7.5-Inch Axle. 1998-2011 Ford Ranger Super Cab 4×4’s are frequently equipped with 8.8-Inch axles regardless of engine size. Click HERE for more Ford … Continued

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Ford 7.5-Inch Rear Axle History & Specs - The Ranger Station

Usage: The Ford 7.5-Inch axle came in a few different vehicles including the: Ford Aerostar (1985-1997) Ford Bronco II (1984-1990) Ford Mustang (1979-2011) Ford Ranger (1983-2011) For the purpose of this article, we’re only going to discuss the Ford Ranger … Continued

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More reading here:

Axle Tech - The Ranger Station

DISCLAIMER: Activities and vehicle modifications appearing or described at The Ranger Station and it’s pages may be potentially dangerous. We do not endorse any such activity for others or recommend it to any particular person – we simply describe … Continued

www.therangerstation.com

 

[Paisano]

Finally! I got some good educational materials from the links provided on this discussion. I bookmarked and started reading.

If I switch to another compatible Ranger model year 8.8, I will not have to reposition the leaf spring and shock absorber mounting brackets........correct?

 

[dvdswan]

Welcome to the site.

 

[Paisano]

Thanks Dave

 

[alwaysFlOoReD]

Finally! I got some good educational materials from the links provided on this discussion. I bookmarked and started reading.

If I switch to another compatible Ranger model year 8.8, I will not have to reposition the leaf spring and shock absorber mounting brackets........correct?

Correct.

 

[Dirtman]

Yup, leafs and shock mounts were always the same on the rangers regardless of which axle it had.

 

[Paisano]

Ok. Thanks. I don't know when I'll do this project. I need to continue reading on this subject.

 

[Paisano]

Hey Guys,

I'm going to put this of till later in the year. It will be cooler and it will give me time to save money to buy the part. I also have to prioritize between this and transfer case replacement. I will follow up