Hey guys, a month or 2 ago i got myself a 96 bronco with about 160k miles on it. Its in great shape, but the driveline always clicks and clunks! I had a small clunk on start off before, but ive since flushed the trans and removed the rear sway bar, so that one went away. Now whenever i come to a stop, there are a series of soft clunks that seem to emanate from the driveshafts, front and rear. Ive tried the grip and shake test on the driveshafts, the u-joints seem ok, but it almost feels like there is too much play in the front diff. Would that even make a difference? Is the front shaft even turning while im in 2 hi? (auto hubs) I will probably change the U-joints anyway, but if there is something else that could be causing I would rather fix that first.

Any insight you guys could give would help, im about to take a 4 hour road trip and dont want any suprises!!

Thanks in advance!

 

If your front driveshaft is turning while you are in 2 Hi it's because one or both of the auto hubs aren't unlocking and are causing the front drivetrain to turn or the t-case is not shifting the front drive shaft to neutral. This adds rolling resistance and lowers fuel economy.

To check - grab the frontdriveshaft while in 2 Hi and turn it.

If it spins freely and makes no noises - all is good;

If it doesn't spin - one of the hubs or transfercase isn't releasing. If this is the case, lift one of the front wheels off the ground and turn the wheel. If it spins and the axle and front drive shaft don't - try the other side. If it turns the axle and driveshaft then your hub is locked in. Hold the axle in place and turn the tire backwards about a dozen times, then try turning it forward again. You might not haev backed up enough to unlock it since the last time it was engaged. If it is locked and won't spin freely to the rear while you hold the axle, the hub is shot and needs replacement. IF both wheels are turning and the axles and driveshaft don't turn with them but the driveshaft still won't turn - it's in the transfer case.

Many of the guys on here prefer the manual hubs over the auto's if you do need to change them out- that way when it's in "Free" you know it's free - and vice versa for "Locked".

As for driveline clunking - more than 0.020" play in the splines on the driveshafts can cause vibrations and clunking. I just had to get the ds on my 89 rebuilt because it had close to 40 thou!

Have a good trip!

Woodler

 

You also should grease your drive shaft. remove the bolts off the rear ujoint, losen the band around the rubber boot, the shaft will slide apart and there you will see the splines that need to be greased. If you read Greystreaks FAQ he writes about this.

Believe it or not greasing this will stop some clunking.

 

Any slop in the pinion on the rear d shaft? these 8.8 have been known to eat crush sleaves, and this will cause a clunk/click

 

Well I got off my butt earlier, and found a lot of play in the wheel bearings, so im going to go ahead and change thebearings, seals, rotors, pads, etc, and ive got a warn manual hub conversion coming too so i can get it done at the same time.

There does seem to be a lot of play in the front pinion, BUT then again, when i turn the front shaft, it will make 1/8th of a turn and stop, so i guess that should spin freely like mentioned earlier? So if a hub is stuck, its going to be replaced anyway, but ill have to check the t-case too.

I have been reading up and im going to grease the slip yokes as well. Thanks for the tips guys.