7.5 to 8.8 rear end questions

Hi guys, I started this thread before and when I was almost done I dropped my phone and it shut off so I lost it, I'm gonna start all over again..
I've been posting like crazy lately, last winter was miserable driving this truck having 4wd problems and all kinds of other problems, I don't want to go through it again, I'd like to get as much done on it as i can and I'm running out of time, I can see winter around the corner.

I've been having all kinds of clunks coming from underneath the truck, at first I thought u joints so I replaced the 2 rear and the front one, that didn't solve anything. After a closer inspection I found out the rear diff was making the weird noises so I put it on the repair list. After thinking about rebuilding the rear end for a while I ran across a ranger with a limited slip differential at the junk yard, so I ran my test and everything passed, so I yanked the whole thing out of it. After a couple hours, a back pain and $120 I walked out of there with a potential upgrade.

To my surprise, after I cracked it open everything looked damn good inside, no worn or broken pieces, no excessive play, everything nice and tight, no bearing noise, no burnt clutch smell, old fluid was thick, clean and clear, no metal shavings, it even has new brake shoes and hardware on it. My friend used to be a "damn" good mechanic back in his days and after checking it out gave me the go ahead and do it. Now, before I get my hopes way up there, I have some questions before I swap it out.

I currently have a 7.5" open diff with 3.73 gear ratio, the LSD I got from the junk yard is an 8.8" but It's still have the same 3.73 ratio, to my understanding it should work without any problems, am I right??? I took everything with it, u bolts, sway bar, brake lines, etc, I don't know how much of it I need to use but I kept them just in case.

I got the aftermarket felpro gasket, fluid and friction modifier already, it looks like it will bolt right up. Is there any suggestions, advice, tips from you guys before I swap it out?? I feel confident but I don't want to do all of this work for nothing. Thanks everyone for your patience.

aside from the swap, look at the hard brake lines.
above the axle where the axle rubber line meets the frame metal line is a common rust problem. be sure to check the metal part for rust, my 2000 broke off there with a slight pull.

being in northern Ohio, the first question we ask is how bad the rust is. hope you have better luck in Nebraska.


speaking of rust, how are your rear spring mounts and shackles?

I did noticed there's been a brake fluid leak right at the fitting on top of the pumpkin on the new one, I don't know what it's called but it's where the rubber brake line goes in and splits into the metal lines going to each wheel from there. I'm planning on keeping most of my original brake lines and other stuff since they're in really good shape, unless I run into problems and I absolutely have to use parts out of the junk yard one. The axle itself is in good condition, just normal rust, and my truck is amazingly almost rust free considering it's 18 years old and lived in Nebraska all its life.
Leaf springs shackles look decent but there's a little squeak that goes away if I spray lube on them, I might replace them if I can find them locally...

As far as I can tell from my research, that "Y" fitting is part of the rear brake hose. You might as well replace it with a new hose. As the hoses age, in addition to cracking and deteriorating from the outside, they sometimes swell from the inside and block flow of the brake fluid. This usually results in locked up brakes, worn pads, overheating, etc.

What year/model did the axle come from?

I believe it was a a 94-95 ranger 4wd manual transmission. A little older than mine but it looked like they took care of it, I don't know why it ended up in the junk yard. I'll go to the auto part store and see if they have one or I need to order it.

Another thing I forgot to ask. The axle shafts move in and out just a little bit, not even 1/8", should I worry about it or is it acceptable? Should I replace the c clips? Thanks..

fr7 said:

I did noticed there's been a brake fluid leak right at the fitting on top of the pumpkin on the new one, I don't know what it's called but it's where the rubber brake line goes in and splits into the metal lines going to each wheel from there. I'm planning on keeping most of my original brake lines and other stuff since they're in really good shape, unless I run into problems and I absolutely have to use parts out of the junk yard one. The axle itself is in good condition, just normal rust, and my truck is amazingly almost rust free considering it's 18 years old and lived in Nebraska all its life.
Leaf springs shackles look decent but there's a little squeak that goes away if I spray lube on them, I might replace them if I can find them locally...

Click to expand...

follow that rubber line up to the where it connects to the metal frame line, check for rust there. the bend in the metal line stresses the coating and allows corrosion. easy to inspect, kind of a bummer if it fails.

fr7 said:

Another thing I forgot to ask. The axle shafts move in and out just a little bit, not even 1/8", should I worry about it or is it acceptable? Should I replace the c clips? Thanks..

Click to expand...

Perfectly normal, it is just a little slop that is required so you can actually get the C-clips out.

I have been to a few JY's in and around Lincoln, good picking over there.

Well, thanks everyone for the advice, I'm excited to see how it works, specially in snow. Hopefully everything goes smooth, I'll keep you updated. Thanks everyone again..

fr7 said:

Well, thanks everyone for the advice, I'm excited to see how it works, specially in snow. Hopefully everything goes smooth, I'll keep you updated. Thanks everyone again..

Click to expand...

There will be some handling differences with a limited-slip rear axle that may trip you up because you are not used to them...


There will be a tendency for your truck to under-steer more on corner entry and with application of throttle that under-steer can abruptly shift to over-steer

And it is that sudden switch that can cause you great embarrassment when you strike another vehicle or stationary road side object....

So be cautious until you re-learn your vehicles quirks with the new (to you)
limited slip axle...

AD

AllanD said:

There will be some handling differences with a limited-slip rear axle that may trip you up because you are not used to them...


There will be a tendency for your truck to under-steer more on corner entry and with application of throttle that under-steer can abruptly shift to over-steer

And it is that sudden switch that can cause you great embarrassment when you strike another vehicle or stationary road side object....

So be cautious until you re-learn your vehicles quirks with the new (to you)
limited slip axle...

AD

Click to expand...

Having 4wd locked in greatly increases the directional stability of the truck, otherwise yeah... it can be a handful if it is slick.

Well guys, I'm working on it, getting it ready for surgery, hopefully I can get it done in the next day or two since I can only work on it at night after work. Thanks for the advice about the difference in handling, I'm aware of it, but I will have some time to get used to it before snow shows up, maybe test it out in the gravel roads for a while and adjust my driving to it. I've driven a e350 diesel van with the LSD before but that's it, I know my truck is super light and it won't handle as good, but hopefully everything goes good. I'll post back once it's done, thanks..