Severe Banging! Tranny? xfer case? or Drive shaft?

[Clintox50]

I want to get some thoughts from ya'll.

My 1995 Mazda B3000 4x4 Manual trans (custom lift ~5in w/ 33's and stock gears) stopped wanting to drive Friday night. It just started going "BANG BANG BANG..." in cyclical repetition and would go faster if I went faster. But the fastest I could/wanted to go was maybe 5mph due to the severity of the noise. And the whole truck would shake when it would bang. Just wondering what the problem could be. I'm worried that it's the tranny ($$$$). Hoping it's just the drive shaft (still the stupid 2 piece design) or U-joints.

I can still shift gears, and the noise is still there and doesn't change rhythm. I was just driving on the street when this started, so not under any real load. But believe me I've put it through it's paces in the past.

I appreciate anyone's thoughts.

Thanks.

 

[BlackBII]

That seems to be likely a driveshaft, have a buddy look under there and look while you creep forward, don't run him over and have him stay back incase it decides to go flying, see if he can tell what id making the noise

 

[Mutant Pony]

Is it a super cab? carrier bearing? It sounds driveshaft related to me as well.

 

[MAKG]

Driveshaft or MAYBE rear end.

Climb under and feel for looseness. NEVER DRIVE THE VEHICLE WITH SOMEONE UNDER IT! Jeez, how do you guys survive to reproduce?

 

[Clintox50]

Yes it is an extended cab. It's got about 160k miles on it (75k since lift). I had to leave the truck at a friends house so I can't go check it right now. I asked my friend to get under there and give the drive shaft a good shake to see if it was loose. He hasn't gotten back to me yet.

 

[Mutant Pony]

The carrier bearing would be the most likely part to fail just driving down the road. Only Supercabs had carrier bearings.
Yeah, just have your buddy hold onto the crossmember while you drive forward (dragging him). If he is a real buddy he will do it! I would!
I'm just kidding, Please don't take me serious. All sorts of horrible things could happen- completely by accident.
At least I understood what BII was saying, Your buddy can be off to the side, Not under the truck at all, and still see what is happening under there.

 

[Clintox50]

My friend got under there and said the main (longer) drive shaft felt solid and the boot (where the carrier bearing is I guess) felt ok. He said where the short shaft connects to the transmission had a little movement, but he didn't know if it was supposed to be that way.

 

[BlackBII]

I didn't mean under it, off to the side, sorry for the misunderstanding

 

[Jspafford]

Sounds like you may need to pull the cover off the rear end to check out the differential.

 

[BlackBII]

I had an old K5 blazer for a while, there was a bad clunking noise similar to that which your describing, it turns out that the pinion nut was loose, causing the pinion gear to lose contact with the ringgear, I took the drivesahft off the diff and tightened her up with some loctite, you may want to check that, now that I recall that instance.

 

[Clintox50]

Sounds like there are a number of things that can cause this sort of noise.

This was some serious banging though, not just some knocking. Like I said it shook the whole truck. And as I was inching down the road to my friends' house people were coming out or looking out their windows going WTF? Of course I had just loaded up about a ton of rock in the back which probably made it worse. It had started making the noise though not quite as bad just as I got to the place to load up the rock so I didn't know what it was before I loaded up. Went about a 10th mile before it got REAL bad and I had to limp it about a half mile back. And then unload the rock that I just spent an hour loading

 

[4x4junkie]

Sounds like you may need to pull the cover off the rear end to check out the differential.

That's probably where I'd look also. Sounds like maybe a chipped/broken tooth on the pinion gear.

 

[Clintox50]

Well I figured out it's not the tranny (thank God) and surprisingly night the drive shaft (althought the carrier bearing has plenty of play). I jacked it up and put it in gear and the noise is definately coming from the rear diff. When I rotated the drive shaft by hand, it was getting hung up on the same spot each rotation. So I'm thinking it broke a tooth off the pinion gear.

I disconnected the rear drive shaft at the tranny and drove it FWD to the shop to let them fix it. I'm tempted to throw in a posi since they have it opened up but as much as I love this truck, I don't think I should be putting any more money into it.

Thanks for all your help guys!

 

[MAKG]

If the carrier is hosed (a distinct possibility), you might as well put a Posi in there, as they don't cost very much more than a new open diff.

But I strongly suspect the cost effective route is to get a complete junkyard rear end in good condition. Chipped teeth have a way of destroying EVERYTHING.

Make sure your replacement rear end (if you go that route) has the same gear ratio, or you won't be able to use 4WD (and your speedometer will be wrong, though that's fairly easily fixed).

 

[Clintox50]

The shop said it's all tore up in there. Pieces are laying on the bottom of the case, pinion is broke, etc. They said it'll need new bearings, races, abs ring, carrier, gears, and axel seals. $1050 and they'll put new guts in it with limited slip.

Just called the local ford junkyard and they've got a completed rear end assy. w/ 91k miles and open diff for $350. But it didn't haveThey said they had a complete assy. with disc brakes too for $600, but i'd have to get all new lines and mess with the abs.

Since I don't have the equip. to do it all myself I can't imagine it would be much less to have the shop put in the used assembly.