2008 ford ranger 4.0 litre random bang when in 4x4

[Ken]

I was driving home the other night after work and it was slippery and snowing so I put my truck in 4x4 and all of a sudden it let out a huge bang. Almost like hitting a large pothole. It never did this again that night but then the next time I was in four wheel again slippery roads and snowing it does it again and a little while later again. What is anyone's thought on what it is? I'm hoping front end issue with gears but I'm not sure since they are turning when it's in 2 wheel drive and it works fine. Also do I need a transfer case out of a truck that has a standard transmission since mine is a standard? Any help would be greatly appreciated. Thanks

 

[franklin2]

Are your front and rear tires exactly the same size? Do you know the history of this truck? Has the front or rear diff ever been replaced?

 

[SenorNoob]

Just tires worn more can be a problem. Also if there is a turn or curve with significantly more traction that can cause problems.

 

[polar8825]

My 2002 did that a couple times when the roads weren't completely covered in snow, usually at relatively higher speeds. There was not enough "slip" when in four wheel drive so the transfer case binds up and the chain finally slips and makes a loud BANG. Scared the heck out of me when it first happened - I thought I hit a huge pothole or something. Going forward, I only run it in 4x4 when it is absolutely necessary. FWIW, I had a Jeep Comanche & a Cherokee many years back, manual part-time 4WD, and I seem to remember the transfer cases being much more forgiving. But I love my Ranger regardless!

 

[Ken]

Are your front and rear tires exactly the same size? Do you know the history of this truck? Has the front or rear diff ever been replaced?

I have noticed that my rear tires are about half tread and the front are almost new. The previous owner did not rotate them and when I got it the rear tires where almost bald so I put two new ones on the front thinking that they'd be close enough but now I'm having my doubts. Since I haven't really driven it in Four wheel drive I never had a issue. But now that I drive it to and from work and use four wheel drive when it's slippery I have noticed that it will let a huge bang at highway speeds and it just feels like it slips when going around 50 km/h in really slippery conditions last time. So I think that I will need to replace the other two. How much of a difference in tread wear will it tolerate roughly? I just hate to replace the two on the front since they are almost like new. Also I appreciate your help with this

 

[franklin2]

They need to be close. You can tell how bad it is by how long it takes to throw a fit. If it's binding like you are describing, you should feel the truck not running as free as it should down the road. In other words, you might need to press on the throttle more than normal. Then the big bang will come and then it should be free again for awhile till it does it again. If you are on dirt, gravel, or snow, the tires will slip enough to correct themselves, and the big bang will not come as often or at all.

That would be an experiment. If you have a long dirt road somewhere, you could drive it and see if it ever did the bang noise. If it doesn't, that is a sure sign the driveline is binding on hard pavement from the tires or some other ratio mis-match.