ylfckthx

I have a hissing noise on my 99 Ranger XLT when I put the vehicle in reverse. I cannot hear the noise in park or neutral. I also got a what I would describe as a clanking noise when I was at a stoplight. The clanking noise is the same noise that I usually hear when I engage or disengage the 4wd. Initially I thought it was a leak in the hub, but the 4wd is engaging and disengaging properly.

Any thought on what it could be, and should I be concerned?

360ci

I wouldn't be concerned, it's most likely your u-joints. If you have mechanical knowledge, a press and a good set of air tools you can change them out easily enough and save yourself several hundred dollars. As you hear it when you engage 4x4, it's most likely the front and rear sets are both shot.

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'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!