Service my 3.73 or upgrade to a 4.10?

[sheliable]

Just changed the lube on my 2wd 3.73.
The old lube was yucky, but the inside didn’t look too terrible no obvious damage or metal shavings. Teeth look good.

Anyways, I still get like a whirring noise at any/all speeds and prominent when deceleration. it’s not terrible.. but I Figure it needs a new ring/pinion bearing. I have a shop that would probably do that repair for me relatively cheap for what it is.

I can’t even tell how bad it is, I mean I can hear the whirring but it’s not anywhere close to as bad as my Tahoe which absolutely whaled on acceleration whenever I drove it. Does anyone else’s diff make some whirring noise but not enough to make you super concerned? How can I be sure it’s the diff that’s making the noise..? Anything else it could be?


Should I just nut up and find a 4.10 limited slip to upgrade my rear end instead? Only thing that worries me is the MPG hit. How severe is that gonna be ?

 

[racsan]

4.10 isnt that big of a jump over 3.73, I think my cruising rpms are 300-400 more than with a 3.73 setup. Might actually gain a little mpg because the engine isn’t working as hard. And if you want to go a little bigger on tires (maybe toss the 14’s if you have them & go to a 15”) I went from a 3.45 rear gear to a 4.10 & love it, I also went from 225/70/14’s to 225/70/15 (winter)-235/75/15 (summer) tires. So my ratio is probably around 3.50/3.60 effectively. If I put the 14’s back on the launch from a stop is incredible, and the cruising rpms are nearly 3,000. Im running a 2.3 lima and 5 speed manual transmission. Towing is greatly improved with the 4.10’s, was hardly possible with 3.45’s Ive never gone from a 3.73 to 4.10 in the same vehicle but Ive had 2 other 4 cyl rangers with 3.73’s and 4.10’s are a improvement. If your engine is a 3.0 then all the better, that motor makes its power higher in the rpm band so deeper gears are always a good thing.

 

[sheliable]

@racsan yeah thanks thats kindof what I've been thinking since reading up on these on here. To be honest, an upgrade like that to me seems intimidating. I feel like it's not worth buying online and paying hella for shipping to get a new rear end to me. and then if I pull one from a junkyard, I'm afraid I'll pull a shitty one and dig a deeper hole for myself. Then I have to find somebody to swap it, which should be doable. I don't exactly have a surplus of money to throw at this. Any advice for someone doing this the first time so I don't break the bank? Like realistically with parts/labor how much should I be looking at to spend on this? I have a lot of tools and have done some decent repair jobs but nothing like this. Tearing out the suspension and replacing the rear end would be all new unfamiliar territory for me.. probably would have a shop do it. I do know a good shop / mechanic for this kinda job though and I don't think he'd kill me on it.

I think I definitely would love to do the swap though.

 

[Dirtman]

It's usually cheaper, and certainly easier for you to do yourself, to just find a complete 4.10 rear and swap it in. Changing gears requires special tools, alot of precision, and alot of skill to do properly. Having a shop do it usually costs more than a whole good used junkyard axle.

Swapping a whole axle can be done by anyone with a breaker bar and a hammer in their driveway in an afternoon.

 

[MikeG]

Changing out a rear axle isn't complicated, but it is WORK. Need jackstands, and jacks (two jacks helps) and an air impact wrench helps a LOT. Oh and did I mention that all the rusty bolts that will likely break? Not a big deal breaking off u-bolts, aren't supposed to reuse them anyway. So, driveshaft, u-bolts, shocks, then brake lines and e-brake cable. Don't know about sensors or what year has what, as far as ABS or anything else.

Anyway it's a doable driveway proposition... with the tools and patience. Did I mention you should have an impact wrench???? Or at least cheater bars. Half inch drive sockets (good ones)..... and maybe douse everything down generously with rust penetrate oil ahead of time.

Just some thoughts.

 

[sheliable]

It's usually cheaper, and certainly easier for you to do yourself, to just find a complete 4.10 rear and swap it in. Changing gears requires special tools, alot of precision, and alot of skill to do properly. Having a shop do it usually costs more than a whole good used junkyard axle.

Swapping a whole axle can be done by anyone with a breaker bar and a hammer in their driveway in an afternoon.

That all sounds well and good but... can you point me to some resource that will give me the piece of mind that I’ll be able to accomplish that job? I start getting scared when I hear about welding on brackets etc etc. maybe that’s just if you’re swapping in a specific axle ..?
I know I want to go to a 4.10 with lim slip if possible... but 8.8 vs 7.5 ??? Never attached a driveshaft to a diff before.. idk it’s just sketchy and seems like it’d be stressful to find help if I get stuck.

 

[MikeG]

You don't need to weld anything if you get another Ranger axle. Do look and see if there are sensor wires, that would limit you to getting one with the same setup.

Otherwise, they're quite similar throughout the years. Driveshaft bolts to pinion with 4 bolts. Stupid easy compared to messing with taking u-joints apart.

Don't need an 8.8 with a 3.0 engine. I doubt you could hurt a 7.5" axle with the 3.0, not till it got loaded so heavy the truck couldn't move under its own power.

 

[racsan]

I did a junkyard swap myself, What I wanted was a 8.8 but the only 4.10’s (just 2) were both 7.5’s ,no biggie as weight capacity is the same, just bigger (10” vs 9”) brakes on a 8.8 and you can swap 10” brakes in later. I paid 200 or 250 for the used axle (hard to remember exactly, I did this swap 3 years ago) The axle had 180,000 miles. I put new seals in it, all new brake hardware and new lines/wheel cylinders. probably spent another 50/100 on that. One thing I didn’t bother with was parking brake cables, I never use the parking brake anyways and with the history ive had of cables sticking & not releaseing I just torched them off. Fresh new oil of course and new cover gasket. Ive not had a problem with it.

 

[sheliable]

What do I do with the old axle after the fact?

 

[sheliable]

Wanna

I did a junkyard swap myself, What I wanted was a 8.8 but the only 4.10’s (just 2) were both 7.5’s ,no biggie as weight capacity is the same, just bigger (10” vs 9”) brakes on a 8.8 and you can swap 10” brakes in later. I paid 200 or 250 for the used axle (hard to remember exactly, I did this swap 3 years ago) The axle had 180,000 miles. I put new seals in it, all new brake hardware and new lines/wheel cylinders. probably spent another 50/100 on that. One thing I didn’t bother with was parking brake cables, I never use the parking brake anyways and with the history ive had of cables sticking & not releaseing I just torched them off. Fresh new oil of course and new cover gasket. Ive not had a problem with it.

Wanna help me do one ?

 

[racsan]

are you in ohio? Its not a hard job, A little time consuming. I had the bed off when I swapped mine, that helped but isn’t nessasary.

 

[MikeG]

Back to the junkyard. You have a truck, after all

Or someone might want it.

 

[racsan]

On the old axle, can always post it on cl or marketplace, or use it as a start to build a trailer.

 

[RonD]

Check car-part.com

For "axle assembly rear with housing"

Yes, you can use 7.5" or 8.8" in a 3.0l Ranger, either 9" or 10" brakes are also fine

You can use a 1993 to 2009 Ranger or Mazda B-series rear axle, 2010/11 had rear disc brakes
Later years "should" have less miles, but not always

Wrecking yards can use different wording for Limited Slip, LS, L/S, Posi, trac-lok
4X4 Rangers often had L/S rear axles, not always but often part of the package

Any will just bolt in, you should use 4 new u-bolts, they are not expensive

 

[sheliable]

Check car-part.com

For "axle assembly rear with housing"

Yes, you can use 7.5" or 8.8" in a 3.0l Ranger, either 9" or 10" brakes are also fine

You can use a 1993 to 2009 Ranger or Mazda B-series rear axle, 2010/11 had rear disc brakes
Later years "should" have less miles, but not always

Wrecking yards can use different wording for Limited Slip, LS, L/S, Posi, trac-lok

Any will just bolt in, you should use 4 new u-bolts, they are not expensive

Hell yeah man that’s perfect. That’s for the tip on car-part.com