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knocking noise

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donbmw

donbmw

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Went to town and had to stop for a couple of cars. Just as I started to move I hear this knocking noise at first I thought is was the ratty truck I was close to. Came back out and was leaving the parking lot and I hear this knocking noise again. I was close to where I work and pulled in and looked under the bonnet. Don't see anything, rev the engine no noise. I first I thought it was the water pump pulley coming apart again. It sounded close to this. The noise is only there when in first gear stops when the clutch is pushed in. Once in second gear or any other forward gear I don't hear any noise. Also taking off in second gear there is no noise. Got back to the house and check transmission oil it was ok. There was no smell like cooked oil from a bearing going out. Starting to back up and can hear the same noise but when the clutch is in you can hear this noise.

To sum up noise when taking off in first gear goes away with the clutch in. No noise taking of in second gear and cannot hear a noise in higher gears. Backing up hear noise with or without clutch.

I am going to look first at the dirve shaft joint. I have had hear noises from them going out when backing up never have heard anything before going forward.

Any one else had something similar. Also going to drain transmission and check for what may come out it time for its change anyway. Hope it is not the transmission.

Don
 
:iagree:
 
Sorry it is a TR3. Have got it on jack stands and the trans tunnel off. I have some play in the drive shaft joints so I am going to pull the shaft and change the joints first and drain the trans fluid and hope I don't find and metal.
 
I am thinking if its a drive shaft issue it would occur in any gear and get louder the faster you drive, kind of a rythmic knock the faster you got the faster the knock gets and when moving. motor issue usually when under load it knocks like a rist pin knock, cam knock it would knock half the engine speed, could be an oil pump knocking had that happen on a not british car. do you have wire wheels with splined hubs and are they tight?

just thinking out loud

Hondo
 
I know what and rod cape coming loose and let the piston hit the head sounds like and a rod bearing galded so bad that to make some noise and this is nothing like those. Right now I am betting on the drive shaft joints. I have had to change joint on 3 other drive shafts they all made a noise similar to this and was at those times only notice when backing up. I hear this noise when the cars slowly rolling backs with the clutch in. I did start the car up on jack stands (I know this is not a good idea) with it in first or reverse you can hear the noise and it seems to come for the joints even with the clutch in and the wheels and drive line spinning down you can hear the knocking.

I do have wire wheels it has not been that long ago that I lubed the splines and recheck for tightness.
 
You can pull the top of trans off and look inside and check the gear teeth easily if you have the cover out.
 
"in first or reverse you can hear the noise and it seems to come for the joints even with the clutch in and the wheels and drive line spinning down you can hear the knocking."

Wheels spinning down with transmission in 1st or reverse and clutch in still allows the offending gears to remain meshed and clunk when the missing , broken, or chipped tooth makes a revolution.

Follow the above recommendation by sp53 and you will, IMHO, find the problem.
 
Update. Removed the drive shaft found the front joint has two bearings going bad with way to much play and two that are notchy. The rear joint is nice and smooth in movement. I start the engine and put the transmission in gear and could hear the still and first and mors so in reverse. Pulled the transmission and will open it up tonite or tomrrow. With it out I put it in gear and rotating the input shaft. I could not fill and hear anything in any of the forward gears but in reverse gear I can fil and hear a loud clonk as you rotate the shaft.
 
Got everything apart and found the first gear couter shaft gear missing the tooth. Now to get the parts.
 
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