FS5W71B 280zx transmisson rebuild

[Dave WM]

hmmm is it possible to put the counter shaft gear on backwards? any offset to the gear, if so that may explain the sound, if the gear is too far forward, coming into contact. There is no mention of this in the FSM but looking closely at the drawing of the shim it looks like it maybe.  If I installed it backwards (if right about that offset, sure looks like it on the pic) then I presume there could be some interference with the case or the main gear. I just don't recall noting it during the installation.

[Zed Head]

The gear in the drawing could certainly go on backward.  I have a vague memory of somebody mentioning that in a different thread.  Might have been duragg over on Hybridz.  He got so deep in to building his transmissions for 7000 RPM shifts that he was hand filing the synchro gears to perfection.

Here's a EuroDat at, he probably has a thought.  @EuroDat

[Dave WM]

well I checked and I installed it as per the diagram, AND I saw no evidence of rubbing on the front housing. Its really odd turn it by hand and very smooth, but as soon as you spin in with the drill, it gets that rubbing inside the bell housing sound. Maybe not rubbing in the housing at all but that is the best way to describe it. even very low RPMs it will do it, very consistently. I tried the drill on the other trans, no odd sounds. If I did not know any better I would think I have a bent main or counter shaft. At this point I am tired of messing with it, had it apart 5 or 6 times now. I even tried spacing off the bell housing, no change. I spun it with the housing off completely (just the bearing plate in the vice). Hard to say as it seemed to want to wobble pretty bad doing that. hard to hold the front plate on to try and align the front bearings. The wobbling at speed bothers me. I guess the only way to know for sure would be to disassemble it again and check the main and counter shaft for out of round. I will have to put that off as tired of messing with it. I guess the take away is I had a pretty loud noise and never really found a seriously bad part. some of the bearings had some noise but I think that may have not been the issue. I can't imagine how a shaft could be bent but I cant think of anything else to account for the warble sounds.

[EuroDat]

I have not been on much lately and just saw Zed heads @ 

Zeds right, you can definitely put the counter gear on backwards. If you do that, it will move the gear about 2mm towards the back. They are matched gears, so fitting the counter gear backwards would mean its an unmatched set and could be whiny.

The other thing that can cause problems in the front area is mounting the 3rd, 4th synchronizer hub backwards, but then you would have trouble with the selector fork pushing the synchonizer hub off centre.

Can you can't remember checking which way it should be mounted? If not, chances are it could be in backwards. It should look like the drawing in your post#37.

In the 1982 FSM page 13 you will see the top left drawing (SMT065) showing the direction the gear should face.

I think I would remove the front case to make sure it's right.

 

 

[Dave WM]

2 minutes ago, EuroDat said:

I have not been on much lately and just saw Zed heads @ 

Zeds right, you can definitely put the counter gear on backwards. If you do that, it will move the gear about 2mm towards the back. They are matched gears, so fitting the counter gear backwards would mean its an unmatched set and could be whiny.

The other thing that can cause problems in the front area is mounting the 3rd, 4th synchronizer hub backwards, but then you would have trouble with the selector fork pushing the synchonizer hub off centre.

Can you can't remember checking which way it should be mounted? If not, chances are it could be in backwards. It should look like the drawing in your post#37.

In the 1982 FSM page 13 you will see the top left drawing (SMT065) showing the direction the gear should face.

I think I would remove the front case to make sure it's right.

 

 

double checked the counter shaft gear mounting did it per the diagram. marked the 3/4 sync before removing and triple checked that installed correct. I am almost thinking a bent output shaft at this point.

[EuroDat]

I had a collegue on the phone and did'nt see you reply.

It could be a piece of grit in a bearing, but I would expect it to be gone by now. A bent shaft, not saying it can't happen, but generally you see something else like chunks of metal in the gears to create such a large sidewards force on the shaft. The gears should show signs of this, like chipped or gouged teeth.

Can you feel it when its ticking?

[Dave WM]

more like a cyclic rubbing sound, I will make a video of it an post later, pretty sure its not a dirt/gear issue, I was careful to keep it all clean and did not open the new bearings until just before assembly. what bothers me the most is when I removed the front and rear housings and spun the input shaft with the dirl there was a considerable about of vibration that seemed to go with the sounds I have been hearing. It only shows up when spun faster than can be done by hand. this was with just the adapter plate mounted on the vice.

[Dave WM]

I can disassemble it pretty quick to test the output shaft for out of round. I just cant justify installing when it makes this much sound. When I spin it at max speed with the drill the warble turns into a near constant grumbling, not unlike what I think was the orig noise I heard when installed in the car the first time.

Only chipped gears was the rev idler, no worse than the JY one I got that does NOT make the sound. It DID have a broken oil gutter when I got it, but it was intact did not seem to go thru the gears just right to bottom and stuck on the magnet. The rest of the gears show no broken teeth.

The only other thing was the badly gouged up rear bushing, I attributed that to the lack of the oil gutter to send oil back to it.

 

Edited October 30, 2017 by Dave WM

[Dave WM]

not really a ticking sound, more like a rubbing sound, seems loudest at the front of the housing.

[EuroDat]

It will be goed to hear it on video. Im having trouble imagining what it could be.

[Dave WM]

well how about this as a test of bent main shaft, I just hold it still (have a drive shaft I can use to secure it) and spin the input (while in neutral of course the sound was there regardless of gear or netural)? that should clear the all the countershaft parts and the input shaft gears and bearings and shims. I don't think I ever did that (hold it still). If the main shaft is not turning then it cant add to the sound.

Not a definitive test of bent main shaft but at least clear those other parts.

Edited October 30, 2017 by Dave WM

[Dave WM]

test done hold main shaft (output shaft, not sure which to call it) still with a drive shaft inserted in the tail housing. NO effect on the noise so that means it must be something in the countershaft or input shaft I guess...

the JY transmission was used to verify, no noise using the same setup (drill and rubber coupling hose). will post the two videos tonight.