99 Ford Ranger 3.0L 4x4 Off Road

[tpginmaine]

Hi All,

Part questions, part edjumuhcation, it's ...questi-muhcation!

I have a 99 3.0L 4x4 off road Ranger bought two months ago. When I bought it the ABS light was on. Since the rear speed sensor (VSS) seems to be a common cause & cheap part, I figured I'd start with the low-hanging fruit. That didn't fix the problem. Not long after I noticed a leak. It was a slow drip off the back edge of the diff. So after highway driving and parking, I'd get maybe a few drips on the ground. Keeping an eye on it & doing some research on differentials, something I know (knew) nothing about, I was preparing to take it apart to check it out. Then I realized it might be the VSS leaking out the top, running down the front and then to the back. Turns out it wasn't 100% seated even though it was screwed in, so I pulled it out, wiped it down, wiped the case & reinstalled it. A few days later, the same drip.

Although the sensor didn't seem 100% seated, I still can't be 100% that that's where the drip is coming from - but I think so. Problem is, it runs down by the pinion seal and all along the bottom, so it LOOKS like it could be the pinion seal, or something else. I've just been keeping an eye on it to determine the exact location, frequency & quantity, but haven't actually done anything yet. I'd say it leaks 2 or 3 drops after 20 miles on the highway each way, each day. I think it was the sensor, so I put the original one back in & cleaned the case again so I can see what happens.

I got the replacement from O'Reilly, and they appear almost exactly the same, except now I think I see the new one has an ever so slightly smaller rubber gasket. You probably wouldn't notice if you didn't have this problem, and then scrutinized them side-by-side, but it is smaller. So I'm hoping that's the end of it.

Ok, so now the questi-muh-cations! First, for obvious reasons, I've been getting progressively more worried about the fluid level, for obvious reasons. I couldn't get the cap off the diff case this morning as intended (3/8 ratchet head didn't fit as I thought everybody says it does?), so I added Valvoline 80-90w Limited Slip through the VSS hole. For very rough numbers, I drive on the highway about 5 days a week and the diff leaked 2 to 3 drops each way for about a month. That's maybe 100 to 125 "drops." Since I drive a little on the weekends and also don't know how much I lose while in motion, I'd say I lost at least 250 drops. A drop is about 1/20ml, so that's 12.5mL or 0.014Qt. I can't find the capacity of the diff, but if it's 2.54Qt as I saw for another Ranger on here, then I lost about 0.014/2.54*100 = 0.5% of total capacity! For a half a %, I probably didn't even need to add any. In fact, looking at that number now, I probably even added too much! (I didn't add all that much, but 0.014Qt seems miniscule). What do you suppose the tolerance of the capacity is? I would think an engine, cooling system, transmission, diff, etc. would have a tolerance of at least a few percent or more on liquid capacities.

Second, I have a diff tag that says S371S at the top. The code under that starts with 4L10 & the door tag says F7. So I guess I have a 7.5" 4.10 LS differential? But does the S371S give more information than that? Googling "S371 differential" doesn't lead to any good additional information.

Third, I read somewhere here, I think, that one could go from the 7.5" 4.10 to the 8.8" 4.10. But why would you?

Fourth, I have a 99, so my 4x4 uses the pulse vacuum hubs (PVH). I hear these are not so reliable? How do I know if they work before winter arrives?

I try to read about all this information: manual hubs vs. auto hubs vs. PVH vs. 'on the fly', 4x4 low vs. 4x4 high, limited slip vs. positrac vs. "open", 4x2 vs. 4x4 vs. all-wheel drive, transmission vs. transfer case vs. differential vs. axle vs. "rear end." But sometimes, I swear I'm more confused AFTER I research than BEFORE!


Any info, advice, clarifications welcome!

Thanks,
Todd

 

[RonD]

3/8" drive should work
Use PB blaster on threads a few times over a few days then try again.
They can be very snug but will come out

7.5" is fine for stock V6, 8.8" came on 4.0l and people often do that swap if they put in a V8.

Take truck to gravel road or dirt lot and shift into 4WD and see if the front wheels pull you, you can feel the difference when you switch back to 2WD, also the steering when cornering will feel different when front wheels have power.

PVH troubleshooting here: http://www.therangerstation.com/tech_library/troubleshoot-fix_pvh_hubs.shtml

As said in this next article Rangers got permanently locked hubs in 2001, called "live axles", this article shows how to do that to yours: http://www.therangerstation.com/Magazine/Apr04/offroad.htm

 

[tpginmaine]

I will check out the 4x4 better. Hopefully it works, but we'll see. I'll double check the differential. Don't know that I need PB Blaster - it's that the 3/8 head was too large for the opening. Close though. Maybe if I scrape away rust & dirt & grime it will actually fit.

Thanks Ron!

 

[RonD]

There are UV(ultra violet) dye kits you can buy for under $40 with UV flashlight.

You can put the dye in cooling system, transmission or axle, as needed, isn't harmful.
Then after a few days you can check for signs of where the leak is coming from.
The reason for UV dye is because it is not visible normally so no visible streaks on parts you were checking.
The dye only shows up when UV flashlight is pointed at it.