I have a 2000 ranger 4wd with the live axle design. It's making a noise that is getting progressively worse when I get to 15-20mph it makes a whom-whom-whom-whom noise and the truck kinda bounces with the noise. If I get over 70mph the truck makes a deep humming noise so I keep it under 70. I noticed today driving home from work the noises get louder while turning either way which leads me to believe it's a wheel bearing. The guy I bought the truck off of said he replaced the front wheel bearings last year and I replaced the rear bearings recently. Could the front diff be making this noise? Any help is appreciated, thank you.

 

Jack up the front wheels and see if bearings are loose
Spin each wheel while its turned one way and then the other way, forward and reverse spin

I assume front axle fluid level has been checked

Drop front drive shaft and drive vehicle that way to see if its front axle specific

 

I did not have time yesterday to jack up the front of the truck but I plan on doing that tonight. Front axle is full, fluid does look old. The front drive shaft is not connected because it needs a new CV. I do not need 4WD at the moment so I have not gotten this taken care of.

With the live axle the front diff is always engaged correct?

 

Yes, front wheels are bolted to each axle so differential is turning when front wheels are, same as rear axles

Front is an OPEN type differential, just FYI, so only 1 wheel gets power in 4WD

I assume you noticed the noise before dropping the front drive shaft?
If noise started after then could be lack of tension on pinion gear, 0 resistance, that's causing the noise, long shot but not a no shot, lol

 

Yes I did notice the noise before dropping the driveshaft but the driveshaft was making its own noise so I decided to get rid of it for now lol.

I just jacked the truck up and checked for bearing play, none. I also spun each wheel each direction with the wheels straight and turned left/right and nothing. It all seems perfectly fine. Could this noise be coming from the transfer case? It definitely sounds like it's coming from the front of the truck. I am out of ideas.

 

Tires?

Rotate front to back, free to try

Yes, transfer case wouldn't be first choice from described area of sound

 

I could get around to that this weekend. RonD I am curious if you know - how hard is it to replace the front differential on these trucks? There's a lot of options on eBay for under $200.

 

Need to match rear axle ratio, of course

1998 and up Ranger 4x4s use Dana SLA 35s, seen here: https://www.therangerstation.com/tec...a_35_sla.shtml
Any of those years would work, the "live axle" or PVH were axle and hub differences, differentials were the same

You need to pull out both axles first so need to disconnect lower ball joint to move hub off of the axle so it can be pulled out
Once the axles are out you should be able to drop the differential out, assuming drive shaft is still disconnected, lol

Be careful of the vent hose fitting on the differential as it can be broken off easily

As said, manual hub conversion is not part of changing differential, but if it interests you here it is
Manual hub conversion seen here: https://www.therangerstation.com/Mag...nversion.shtml

i.e. if you were to buy a complete 1998-2000 front differential with axles..................

 

Did you ever figure out the issue? I am having similar issues with my 2011 Ranger XLT 4x4. I replaced both hubs disconnected the front drive shaft and when I get to 20mph the rotational noise starts. If I’m going 30mph down hill and let off the gas it is very loud and almost sounds like going over rumple strips. It doesn’t pull and I don’t really feel it in the wheel or pedals.

 

Unfortunately I had to sell the truck as I am moving out of state. I didn't figure out the issue but I have a feeling it was the front differential. I was going to buy a used unit on eBay for $150 and swap it out but I didn't want to waste the money if it wasn't the issue. Good luck to you.