clunking thuding sound under transmission hump

[2 mazdas]

i posted a few months back about my thuding under my 94 mazda b4000 ext cab 4x4 i bought this truck wrecked and it didnt have this sound till the body shop pulled the frame back to specs. thought i had a busted tranny mount so i replaced it and made the sound even worse cant see any where under truck where anything is rubbing,also it does not make sound at all when raise back wheels of ground does this noise in or out of 4 -wheel you had suggested sagging cab mounts before they are all fine and also bad radius bushings they are fine also im really stumped here need help thanks 2 mazdas could the transfer case be bad? ive checked u-joints also the sound would come and go before i put new tranny mount in and now it is all the time help again thanks

 

[kennykenny]

Mostly likely the slip yoke thud, try greasing it.

 

[2 mazdas]

thuding sound

Thanks for the info i will check it out. all i know is it sounds like litterally the drive shaft is rubbing as it turns it just goes thud thud thud constantly. than ks aloit ill try this and let you know if you think of anything else to check let me know thanks again.

 

[fordzda]

Thanks for the info i will check it out. all i know is it sounds like litterally the drive shaft is rubbing as it turns it just goes thud thud thud constantly. than ks aloit ill try this and let you know if you think of anything else to check let me know thanks again.

You say you checked the u-joints did you remove the d/s to do this? sounds like a seized u-joint.

 

[kennykenny]

If it's consistant its probably not the slip yoke then.

 

[2 mazdas]

2 mazdas constant thuding

You say you checked the u-joints did you remove the d/s to do this? sounds like a seized u-joint.

thanks for the info i hadnt had a chance to get back with you i checked the ujoints and they are not seized up any more ideas? thanks for help let me know

 

[red93terror]

i had this same problem and all it was were my front drive shaft bolts. they backed out quite a ways. check for that

 

[redneckbl89]

if you have a 2 piece drive shaft, check your center support bearing. it should be on a cross member that supports the front of the gas tank also. they have a tendency of goin out. i was having the same prob with mine and after i replaced it, it went away.

if u want a pic let me know and i can get you one.

 

[2 mazdas]

thudding sound

thanks for the info on carrier bearing i wondered about that is there any way to check it? let me know thanks again.you say you had the same thudding sound constant and that fixed it? how much are these? do you remember?

 

[Rifleman]

Park on a slight grade, in gear or park, with the parking brake set; If you shake the shaft at both sides of the carrier bearing and there is ANY movement at all it is bad.

They are not expensive, try www.rockauto.com.

Another thing, where was the truck hit? I've seen axleshafts split from side impact and make a griding noise at low speeds and knocking/banging at higher speeds and be perfectly quiet with the weight off the wheels. Pretty much the same thing you describe.

After driving the truck a short distance trying to make an equal amount of right and left turns. Feel both of the axle housings (to the right and left of the rear differential) and see if the temps differ between the two. If one side is hotter than the other it is an indication the axle shaft is split (hot side). Do not do any hard cornering if you beleive this to be the case and do not drive it beyond getting it home.

 

[CJREX]

If it's indeed the carrier bearing, don't replace it.

Convert to a 1-piece driveshaft.

Cost will be about the same and results will be much better, especially if you ever plan to lift it.

I think I paid around $80 for my 1-piece driveshaft.

http://www.therangerstation.com/Magazine/June04/offroad.htm

 

[2 mazdas]

thudding sound

thanks for the info the truck was hit in front right inside driver frame horn. thanks again so should i still check rear axles? let me know

 

[2 mazdas]

thudding sound

if you have a 2 piece drive shaft, check your center support bearing. it should be on a cross member that supports the front of the gas tank also. they have a tendency of goin out. i was having the same prob with mine and after i replaced it, it went away.

if u want a pic let me know and i can get you one.

you say that your truck made the same thudding sound and you changed the center support bearing and it fixed this sound? let me know thanks again

 

[AllanD]

Ok, Time for me to settle the issue...

Check the condition of your rear cab mounts.

They aren't making the thudding but they reduce clearance for the real cause.

DIRECTLY above the rear output flange of the T-case where the rear driveshaft bolts up there is a reinforcment in the floor that supports the rear of the seats

On the raised flange of that reinforcement there will be a tint witness mark, no biggern than a centimeter square.

The rear output flange is just "kissing" the reinforcement, but because it's
spinning when it does it makes a considerable noise.

Because it's so small the witness mark typically escapes notice.

Now ask me how I know about this...

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