BAD Drivetrain noise!

Here's what I have: 1955 CJ,rebuilt engine, (f-134) rebuilt tranny,(T-90) andT-case (spicer 18) New U-joints on the driveshafts, new wheelbearings,kingpins.Ring and pinions look okay.Her's the problem; when the vehicle gets up to 25-30 mph,a sound comes from underneath the floor that can only be described as if you put a handfull of gravel in a blender and turned it on! The sound is there only under load(when accelerating), it goes away as soon as you let off the gas. The noise was there before the rebuild.thought it was a tranny/ t-case problem,but apparently not.It's hard to tell where the noise is coming from exactly, but it seems to be in the area of the tranny and forward.Any ideas on this? Thanks. :?

 

Let's think about this. Rebuilt T90, you did fill it with gear lube.... That can't be it. Rebuilt TC, also has lube in it, right? That can't be it, but they do make a nice (to me) whine cause of the middle shaft and bearings. Clutch. If there was anything wrong in there then you would have known about it long before now. Front axle, ain't locked in so that ain't it. And rear axle is too far back to do it. That leaves only the tranny, and transfercase.
Is this in 3rd gear? Is is quieter in 3rd? If so, then the problem is with the tranny. Probably a worn gear, or really bad bearing. Rebuilt?? Maybe assembled wrong? Transfercase could do it, but it is doubtful.
Engine? Not bloody likely, Or it would make noise at idle.
Other than that, I have not a clue!

-Hill

 

I'll bet a 12 pack that the tranny or transfercase is touching the tub. Or one of the three sticks is rubbing the tub.

JB

 

I'm with you. Seems like if it were a bearing in the tranny, it would make noise on compression also. Same with the T case.

 

Could be body touching the drivetrain. If you let off the gas and the noise goes away maybe you should check the motor mounts?

This same symptom (noise stops when letting off the gas) could also be a drivetrain problem. I was recently bitten by a worn out dana 18 transfer case intermediate shaft so would suggest you pull the t-case pan and check it out. Everyone says it'll be real noisey but the whole rig is noisey!

 

I have a rattle of tailpile to frame at times. To be fixed real soon. Same type of sound - took me forever to figure it out.

 

New motor mounts, new T-case mounts,the E-brake drum has been removed (for rebuilding), new body mounts. The tranny and T-case were rebuilt by a good 4x4 shop, and the noise is the same as before the rebuild.Can't see them missing anythingor leaving anything out, but I guess it's possible.($850 rebuild,I saw the parts they replaced) This one's driving me crazy(and stopping me from driving!)

 

Doubtful this would result in your symptoms but, driveshaft out of phase?????

 

The front driveshaft was bent,but replaced after the rebuild,didn't help. Thanks for input anyway

 

Did someone mention the anti-torque(ie) cable thingey? Someone had pics.

A little help over here with the F4 stuff. I don't know these exotic slow moving creatures.

 

Have you checked to make sure that there's not a blender under there with gravel in it?

 

R)

I gotta tell ya the way you describe it, it sounds like an intermediate gear/shaft. There were some real bad int. shafts on the market.

 

Kelly, from what you have told me in the PM's I'm sure I'm wrong. I would refer you to nickmil for further advice. Keep the discussion here so others may benefit.

 

Is it a single stick transfer case? If so, sometimes the shifter has to be adjusted so it wont "rub the tub" to coin a phrase. Another thought is rear pinion bearing. If it makes noise on accel. but not on coast. Just a couple idears.

 

It's a twin lever t-case, Im sure the levers are'nt hitting the tub.But you gave me an Idea, could it be the front Diff. If I took the front driveshaft off and drove it to see if the noise was still there? Would removing the front driveshaft do any harm if driven?