Rear Tires Lock at 60mph...

[saveatreeeatabeaver]

Hello all,

While driving to work the other day, the rear tires on my ranger locked up. I managed to keep it on the road (it was a sweeping turn), though I ended up blocking the road. I restart the truck and am able to limp along for approx 200 yards before it happens again. Based on the tracks in the sand, it appeared that only one tire was locking up this time.

Symptoms I've been having.
- Diff had a slow leak. I replaced the cover and used gasket seal, though it seems I did a half-assed job. After getting the truck home, I took the cover off and had no oil, just sludge
- The ring gear and smaller gears held by the pinion were slightly rough, but not too bad...
- While driving, after the lock-up occurred, and in my driveway, the grinding was so loud that i didn't dare take it out of second.

Truck is a 2wd, 1996 2.3 liter. 7.5 axle.

Any advice that will help me to diagnose the problem would be appreciated.

Thanks!

 

[shovelmike]

Not good news

It sounds to me like the bearings that support the carrier in the rear end and possibly axle bearings and gears all may be severely damaged.
You would probably be money ahead getting a whole axle assembly from the salvage yard.

 

[saveatreeeatabeaver]

Ratio Unknown

The previous owner damaged the door and replaced. This same owner, or road salt, removed the tag on the diff. As far as I can tell, I have no way to checking to see what gear ratio I have.

I've heard of "counting the teeth", though I'm not sure what that means.

Any other ways to figure out the gear ratio?

 

[Captain Ledd]

The previous owner damaged the door and replaced. This same owner, or road salt, removed the tag on the diff. As far as I can tell, I have no way to checking to see what gear ratio I have.

I've heard of "counting the teeth", though I'm not sure what that means.

Any other ways to figure out the gear ratio?

it'll be stamped on the edge of the ring gear. Keep twisting it around and you'll see some markings between the teeth and where it mounts to the carrier.

Some will have the actual ratio number on it, other's I've seen just list the pinion tooth count and the ring gear tooth count. Divide them it will tell you the ratio.

*edit:

You're likely going to have 3.55 or 3.73.

Counting the teeth refers to counting the teeth on the ring gear, and the number of teeth on the pinion gear. Count them and then divide them.

Larger number divided by the smaller number.

 

[fastpakr]

Since it's a 2wd you don't have anything that the axle needs to be matched to. I'd just look for a 3.73 or 4.10 axle regardless of what was in there to begin with.

 

[Ranger Sport Honduras]

what trans u have? manual or auto?
its possible that u have a 3.73 or u have a faster 3.55 or even faster ratios where available.

if u feel like u could use a bit more power on the truck,
a 3.73 will do, since i guess ur using 14" rims. that ratio will give decent power and good driving rpms, so it will give a good mileage.

if u feel like u need more acceleration and dont mind driving a couple rpms higher, look for a 4.10

 

[saveatreeeatabeaver]

Truck has a 3.45 gear ratio, determined by counting teeth. It is also a manual transmission


I was under the impression that the replacement axle had to be the same ratio as the one removed? Is this isn't the case, I'll search around for one that'll get me the slightly better mileage.

 

[Captain Ledd]

Truck has a 3.45 gear ratio, determined by counting teeth. It is also a manual transmission


I was under the impression that the replacement axle had to be the same ratio as the one removed? Is this isn't the case, I'll search around for one that'll get me the slightly better mileage.

sort of.

You'll need to replace the speedometer gear with another gear with a different number of teeth on it so it will read correctly. They're color coded, if I had more time I'd post up some more information. THIS gear change is actually really freaking easy, one 10mm bolt and it's easy to reach.

Do you do a lot of towing or have loads in the bed?
Primarily city driving or expressway driving?
Maybe the ratio of city/express?
What size tires do you have?

We can give you a detailed example of what to look for and what to expect with those questions answered in terms of gear ratios.

 

[Ranger Sport Honduras]

His is a 96, so it has the electric speedo. no need of speedo gears.

 

[Captain Ledd]

His is a 96, so it has the electric speedo. no need of speedo gears.

Mine is a 97, and I just replaced my speedo gear to adjust for larger tires.

If it's off the transmission or transfer case, you'll still run a gear. It just turns a sensor instead of a cable. If there are no wires anywhere around the transmission output or the t-case output, then it's ran off the rear axle's tone ring.

This is the part you change:

16, 17, 18, 19, 20 tooth gears. (21 tooth is red, not shown)

The one that's harder to replace but doesn't really need to be changed is the one you will see through the hole. It is also identified by color.

White = 7 tooth
Red is supposedly 8 tooth.
if it's a different color still, it's probably a 6 tooth.

Use this formula to determine which gear you'll need:

Drive gear teeth (6,7 or 8) X Axle ratio X Tire revolutions per mile

Divide that number by 1000.

An example: (using a 235/75r15 tire)

6 x 4.56 x 698 / 1000 = 19.097 teeth, so a pink 19 tooth gear.

This will work for any axle ratio you put in, if you decide to do something other than stock that is.

 

[Ranger Sport Honduras]

I see. my 99 has no wires coming from the trans except the reverse light switch.
the sensor is in the diferential.

Thats why i assumed all 95+ where like that, since they went with the electric speedo when they did the dash redesign.

 

[Captain Ledd]

I see. my 99 has no wires coming from the trans except the reverse light switch.
the sensor is in the diferential.

Thats why i assumed all 95+ where like that, since they went with the electric speedo when they did the dash redesign.

To the best of my knowledge, they went off the rear diff in 98 along with the front suspension redesign.

 

[saveatreeeatabeaver]

Thanks!

Excellent info guys, I appreciate it. With this info, I'll continue searching for an axle.

My VSS is located on the transmission, in the vicinity of the front drivers door. I do indeed have the gear, as pictured above. Had to put in a new VSS a few months ago after it decided to quit.

To answer you questions, the vast majority of what I drive is country roads at 55-60 with 5% or less of city driving, if two stop lights can be considered a city. If I understand it correctly, it'll be better for my mileage and not hurt performance if i attempt to buy a axle that is a smaller number. I have not problem downshifting for hills.

Last question. Anyone have any good photos or descriptions for replacing the axle?

Thanks for the assistance!

 

[Captain Ledd]

To answer you questions, the vast majority of what I drive is country roads at 55-60 with 5% or less of city driving, if two stop lights can be considered a city. If I understand it correctly, it'll be better for my mileage and not hurt performance if i attempt to buy a axle that is a smaller number. I have not problem downshifting for hills.

Last question. Anyone have any good photos or descriptions for replacing the axle?

Thanks for the assistance!

Since you're not really having a problem, find an axle with the same ratio. Though you'll probably come across a lot of 3.55's, which is still really close.

It doesn't sound like you need to go shallower (3.27 or 3.08) And actually, the 4 cylinder makes it's power higher in the RPM band, so going with a ratio that will limit engine RPM will make the engine work even harder to keep going. Resulting in even less performance, and in most cases even less fuel economy.

A deeper gear (3.73 or 4.10) will help acceleration, but it can hinder highway fuel economy depending on how fast you like to drive. If you keep it to about 60/70mph on the freeway a 3.73 axle shouldn't effect much at all, and give a little extra low end grunt starting out. With a 4.10 axle you might see some changes in the red at highway speeds past 60mph. Again, some of these depend on tire size too. MOST see a slight mileage improvement going to a slightly deeper gear, but not all of them.

As for replacing a rear axle, really straight forward.

Unbolt the driveshaft - 4 bolts
Unbolt the shocks - 2 bolts
Disconnect the parking brake cable
Unbolt the sway bar - if you even have one
Unbolt the u-bolts on the spring- 8 nuts in total
Slide rear axle out from under the truck

Install in reverse order.

 

[Ranger Sport Honduras]

i love the 4.10 on mine