Driveshaft Freeplay

[Pomorza]

Hey mates

 

So to fix my shifter vibration I pulled the shifter out to do the brass bushing replacement. To my amazement it was already done, but since I wasted all the time walking to the store I figured it'd do it again. Pulled the old brass bushings out and squeezed the new ones in. After some filing and help from a mallet everything was back in to place. Before I buttoned everything up I checked up on my driveshaft. I replaced the drive shaft back in 2009 with a new one from MSA - the one with greaseable ujoints. Question wise, what is acceptable for veritcal - up and down - movement of the driveshaft. There is a bit of play up and down. Otherwise everything seems well. Saldy the noise is still there.

 

Thanks

Jan

 

Edited:
I grammar good.

[Mark Maras]

I don't know the answer but I'm curious how much movement you have, any movement in the u-joints or a very high speed vibration at 85 mph or above?

Mark

[madkaw]

Horizontal-up or down play-seems contradictory.

Are you separating U joint from other issues?

My shaft had issue at the rear of the trans. I could grab the DS at the yoke(while installed) and move it up and down using moderate to hard force. The movement was enough to be audible. When I had my t-5 rebuilt here recently, the builder said the tailshaft bushing was elongated and he replaced it. What I experienced in the car was vibration at higher speeds-maybe this was the issue? i don't know since the car is apart now.

There really shouldn't be any movement that can be produced by hand in the driveline.

[Pomorza]

Wow didn't realize the gramatical mistake there. by horizontal I clearly meant vertical. If I grab the driveshaft just ahead of the u joint and pull up there is a slight amount in the up and down way. I can also rotate it slightly - when the car is neutral.

 

Thanks

Jan

[EuroDat]

Sounds very much like a worn extension house bushing. There is a guy on hybridz that had a similar problem. It was leaking oil all the time. He had a worn bush in the extension.

He was also having trouble with after market stuff being out of spec in new condition. Something to be aware of if you are buying parts to fix the problem. Can't find the thread right now.

I think you are refering to the backlash in the diff when you rotate it in neatral. You are turning the driveshaft to the diff right? Slight rotation is normal and shoundn't be causing this problem.

Chas

[Pomorza]

Chas

 

Interestingly enough my transmission doesn't leak, or doesn't leak enough for it to leave any noticeable marks on areas where I park for extended periods of time. Last year - about mid November - I had the level check as I had a suspision it maybe low (seemed oddly warm after drives, I have a post on here about it, it would sit at about 160ish temp wise) and the fluid was exactly where it should be, maybe even a tad bit overfilled. (I use Redline mt-90).

 

As for my issue, I do have a bit of an update. I drove to work this morning per usual. Other than a slight shifter vibration in 1st and 3rd the noise seems to have gone away, or at least become very quiet where it can't be heard. (I do have a failry loud exhaust ). Also want to point out when I was reassembling the shifter the little cover that holds the shifter seal (the large black thing around the shifter on the floorboard THIS.) one of the bolts refused to seat, it would tighten but only a few turns and then give way.

 

Thanks again mates

Jan

[EuroDat]

Jan

A couple of other things you can check are:

The bolts in the rear transmission mount are not too long. If the mount starts to sag and the bolts are long, they could tap the top section and cause the noise during certain frequencies.

Do the brass bushes have any excessive play on the internal diameters. I know of one guy having this problem with new brass bushes and changed back to plastic and the noise went.

Sounds like its getting better. Just in 1st and 3rd sounds bearing related and maybe a little mis alignment of the gears.

Chas

PS: The guy on hybridz had an oil leak and found the excessive play in the yoke. It wasn't causing him vibrations, not even sure it was causing the leak, but it could vibrate if it started clicking up and down on the shaft splines. Some oil leaks come from the pin above the selsctor rod. Its not sealed which was probably a source for his leak.

[Pomorza]

Chas

 

Thanks for the help. There is literally no play in the pin inside the bushings. I used to wrong sized diameter and had to take off 0.020" to make the pin fit. I used a mallet to get it in all the way on the car so there isn't any play - or very very little. Could it at all be clutch (or related bits in that area) related. I only ask as when the car is in neutral it makes a fairly noticable noise. I think its the throwout bearing - as this is the same noise my brother's 620 had before we swapped the clutch - but it could be something transmission related, it is well over 30 years old.

 

The other thing I noticed is with the shifter out there was some fluid at the top of the trans, where the little circular bit on the shifter goes. When I drove it with everything off - to inspect the trans while I drove - I didn't notice any of it pouring in there, but there was definitely some in there. (it also looked fairly old).

 

Thanks mate

Jan

[EuroDat]

Hi Jan,

 

Is the notacable noise in neutral with the clutch engaged or disengaged?

The throwout bearing should not be noisy when disengaged. The bearing is then unloaded and bearly touching the pressureplate fingers. It would be more likely something like the center needle bearing (in red circle) between the input shaft and main shaft.

You could remove the dust cover around the clutch fork so you can hear it better. It may help localize the noise.

 

A possible oil leak source is the locker pin (see red outline in cross section) for the selector rod. Its between the breather section and the o-ring seal on the selector rod. I used silicone sealant around the housing and over the ends of the pin to cure my small leak there.

 

One other thing you could try to help fix your rattle is the check ball springs on the selector rods. They could be worn and weak allowing the selector rod to jiggle and vibrate. The two side checks (3rd,4th) (rev,5th) are easy to remove, but the one up top is harder to get to and get out.

You could try a set of new springs or shorten the exiting springs and add washers to equivalent to the amount removed. Shortening the spring makes it firmer. It would be easier to buy a new set of springs. I replaced them P/N:32830-20100 in my transmission and they only cost €1.00 ea. The new ones were a couple millimetres longer indicating that my old ones had saged a little.

 

Maybe something there will help

Goodluck

Chas

[Pomorza]

Chas

 

Thanks for all the information. Yes what I mean is when the clutch is engaged in neutral - as in the clutch pedal is released (not being pressed what so ever) and not being touched, the trans makes said noise. When I press the clutch down - disengage said clutch - the noise goes away (though my terminology maybe wrong but I always assume engaged is when the pedal is not being pressed). I brought that up as my brother's 620 (soon to be mine) had the same issue. When we pulled the transmission off (five speed update) and did a clutch the old T.O bearing was extremely hard to turn by hand.

 

Thanks again

Jan

[EuroDat]

Your description is right. Clutch engaged is when the peddle is not being pressed to the floor. If the throwout bearing is seizing (hard to turn) it could be slipping on the pressureplate fingers when the peddle is not being pressed. I would expect it to be making noise all the time though and when you depress the clutch it should protest even more under load.

Not being able to hear the noise myself Im leaning towards internal noise in the transmission. It could be bearing wear and that could be causing your selector to vibrate as well.

You could change the check ball springs in the selectors to reduce the effects and cure the rattle, but if the bearings are causing it, they will only get worse and you will eventually need to do some sort of revision or transmission replacement.

Chas

[Zed Head]

The noise from the transmission in neutral, that goes away when you press the pedal, is very common.  All of mine have it.  jmortensen posted in the past about helping someone change a bearing because of the noise, I think it was the countershaft bearing or maybe the mainshaft, and having a quiet transmission for only a short while.  The noise came back.  

 

If we asked everybody on the forum to listen for the noise, we'd probably create a run a on bearings or rebuild kits.  Ssshhhhh.....

 

 

Wow, my first attempt to find that old post and it popped right up - http://www.classiczcars.com/topic/35592-throwout-bearing-noise/