I have a 97 f150 4x4 with a awful rear end clunk when going from a complete stop to low speed or from reverse to back up at slow speed " CLUNK!!" once I get out of first gear it doesn't do it. If I ease on the pedal to speed up really slowly it doesn't do it. I had a friend drive it back and forth repeating the clunking sound in my driveway and it looks like my rear end differential is flexing a whole lot more than it should. I checked both universal joints they are fine with no play although the rear universal joint bolts where kind of loose but I figure thats from the terrible flex From the rear end. The leaf springs seem fine. There's no busted shackle or anything so I'm really lost on this. I hauled a load of dirt to fill some low spots in my yard and it started maybe 2 days later. I have the smaller 8.8 rear end if that matters.

 

This is my first post on here I just need a little advice please. I joined this forum just so I could ask you guys personally. My questions are always answered until now ( I look on here all the time for other problems and maintenance information )

 

What about if the truck rolls in neutral, does it still make the clunk? There are a lot of things to look at, such as the U-joints, pinion, trans, etc. If you grip your drive shaft (while in park) can you spin or move it at all?

 

Grease the rear slip yoke. Depending on mileage the rear bearing may be worn out. There is a lot of different thinks.

 

I haven't tried to see if it made the noise in neutral I'll have to do that first thing in the morning. The driveshaft had no play in it, I will have to take a look in the differential and grease to..The transmission should be good I just had it rebuilt last year. when it makes the loud clunk sound the rear end kind torque up towards the driveshaft is that normal? Just seems like something is out of whack. Could it be worn leaf springs? The universal joints seem fine to.

 

If everything is tight, grease the slip yoke on the driveshaft.

 

Sounds like ur pinion bearings are shot just saying cause I just had the same.problem

 

Put a wheel choke on front wheels ,Raise the rear end tire off the ground enough to spin it put the transmission on neutral . Spin one tire. Then s stop it .while listening to where the noise is coming .its either your pinion bearing , driveshaft or wheel bearing . And it even better if you go under the truck to spin it .so you can hear clearly .good luck.

 

Mine made the "clunk" sound and greased the slip yoke but it was still there. My cluck was coming from the transmission mount nuts being lose. When the truck was started or driven, the engine would Tq up, moving the transmission and binding it up. The cluck was the trans popping out of its bind.

Sometimes it would do it in reverse, sometimes when turning and often when the truck was sitting in the driveway and settling.

 

Thanks for the response guys. I took my Differential cover off and 3 big metal teeth just fell out on the ground.. it was teeth from the spider gears.. had it towed to a local shop and upon further inspection the pinion and everything is ruined. Needless to say he quoted me 1400$ for a complete rebuild including labor. Is this to much? Or does that sound about right? I don't wanna get a junkyard one because I don't want this same thing to happen again. I've already replaced engine and transmission in this truck.. so is it worth the 1400? What do ya think guys ??