5 speed tailshaft bushing in a 4 speed

[DuckManNK]

On 1/20/2021 at 11:23 AM, EuroDat said:

Hi DuckManNK,

The bush was replaceable it the 4 speed and had a slightly larger outside diameter iirc. The 5 speeds had a thinner bush and was no longer considered a replaceable item. Worn bush meant replace the rear extension housing.

The bush you are quoting is for the  later FS5W71C transmissions used in the later 4 cylinder Z series engines (Z22 & Z24 etc.) The transmission is a stubby version, meaning shorter rear extension housing and the propellor shaft is also shorter and some fitted with a two piece shaft and center bearing. This all reduces the stress and wear on this bush. The bush is therefore the same outer and inner diameter, but much shorter in length.

It will work, but it will wear out faster than the original FS5W71B 5 speed bush.

Search for Omega Machine Tool 71411. That bush is almost identical. The dimensions are the same, just slightly different lubrication groove.

https://sales.omegamachine.com/Nissan_FS5W71C_Extension_Housing_Bushing_p/71411.htm

It's also a lot cheaper than the Nis 62.

Hey thanks for the info. I had actually already ordered that part from Omecha Machine back in November and forgot about it. Apparently they did too. I called them and they told me that they changed part order systems so it was just never sent.
I am finally making time to remove the transmission and give replacing it a go.

[DuckManNK]

On 1/20/2021 at 5:47 AM, dutchzcarguy said:

Welcome here on this site,

Have you installed the right yoke .. there should be ZERO play on the driveshaft is you try to shift it from left to right..(and up and down..)

Also, i think you did'nt use the right seal (twice) on your gearbox outletshaft..   (as far i know you can use the seal from a 5 for a 4 speed gearbox.)

Again there should be NO play on the driveshaft it will leak oil after a short while, the new seal gets worn fast. 

And.. pictures can help..

 

So will a National seal #710324 not work?
 

[DuckManNK]

This is the amount of play the yoke has:

 

 

[Zed Head]

My imagination says that seal is not actually tight on the slip yoke.  Can't really tell from the video.  I notice that the aluminum seal seat is kind of dinged up also.  Could it be that the tail shaft housing is cracked, or gouged?  There are two sealing surfaces, one at the yoke and one at the housing surface itself.

I used to have several shafts and transmissions out in the garage but don't now, otherwise I'd be out there comparing slop.  Maybe somebody here can do that.

And, more spitballing, there seems to be a lot of fluid up at the front of the dust cover.  Still wondering where, exactly, the fluid is leaking from.

Last one - the yoke seems like it should be seated farther in to the transmission.  That would affect how much support the bushing gives it.  Might be an illusion because the dust deal has been removed, but usually the shaft dust seal inserts in to the transmission dust seal.  Your propeller shaft looks too short.  There is a short version of the shaft out there that was used on the very early 71's.  1 1/2" shorter, I think.

Is the shaft fully installed in the car or did you just stick it in there for the video?  And, what happened to the dust seal?

[EuroDat]

The play in the bush looks excessive in your video, but you shake it up and down so fast, it's hard to judge how much. It could also be showing movement in the transmission mount. The fact that it is making noise when you shake it is also a sign you have too much clearance somewhere.

One theory. It could very well be causing your leak even with the correct sized seal. Nothing is absolute. Everything we design has tolerances. Same rule for the balance of the proppeller shaft. It will sling out towards its heaviest point. That in turn will push the seal lip away from centre as the slinger motion moves around the rotation. At high speeds this action pushes the seal lip out, but the lips reaction time is not fast enough to return and maintain a seal on the opposite side of the slinger.

If you have 1mm play in the bush, the seal will move 1mm in and out every revolution. At slow speeds the reaction time will keep up, but at higher speed the reaction time of the seal can't keep up.

If this is happening, you should notice a vibration in the gearshift knob. Not saying this is the cause, but I have seen this on variable speed feed pumps on a pasteuriser. No leak at low speed, but leaked at hidh speed and vibrated until we changed all the bearings.

I would strongly reccomend using an original Nissan seal for your next attempt. Try to eliminate variables. The Nissan part  number 32136-U010A is specified for this application, where the National could be a seal that fits a range specification and you could be near the limit for the seal. Add a couple of tolerance here and there and you have a leak.

The seal size should be 35/50x11mm. Metric.

[dutchzcarguy]

15 hours ago, DuckManNK said:

This is the amount of play the yoke has:

Well.. THAT is MUCH to MUCH play!!!  The spleens (Hope i have the right words haha)  In that yoke have to meet the spleens on the out-shaft perfectly.. with no play, i can clearly hear in your vid. that it rattles..  I looked at the vid few times at it seems to be that your propshaft does NOT fit your gearbox at all!

Also i hope you hadn't installed the propshaft, (just holding in your hands) if the shaft was installed, it's a to short shaft!   (Like zedhead sayd, from a diff car year..) Get yourself an other propshaft, with good spleens in it and look if your spleens on the outputshaft of your gearbox are not damaged!

Must i say it... again.. there should be 0 play on that..  remember also, if your driving in 4 of 5th gear at high speed, that propshaft turns at a very high speed!   If that connection breaks  there is a possibility that tha shaft will hit the bottom of your car very hard, some say that it can take off your leg(s) if your really unlucky !!    So, don't take it lightly.

btw, if i see the video, i'm surprised the oil does not leak out immediately..   The play is also that big because your yoke is not pushed far enough onto the outputshaft.

[EuroDat]

The proppeler shaft should have a uni-joint center of cup to center of cup measurement 575mm. The shorter version should be 525mm., give or take a couple mm. I took these measurements with a tape measure.

The 280Z with non servicable uni-joints is 565mm and the 2+2 is 865mm.

Looking at the screen shot Zed Head made, I don't think you have the short one. It doesn't look like you can get another 50mm between yoke and tranny housing.

You can see where the seal was in the my photo's.

 

[DuckManNK]

I think I found my issue....

There is no bushing....

💀

[zKars]

I have a “B” type 4 speed (71.5-78) I’m going to part out and recycle. Saving only the front case and input shaft at the moment. I can remove the bushing and send it. 

[DuckManNK]

4 minutes ago, zKars said:

I have a “B” type 4 speed (71.5-78) I’m going to part out and recycle. Saving only the front case and input shaft at the moment. I can remove the bushing and send it. 

Thanks! I might take you up on the offer.

I ordered the omega machine tools bushing and installed that right now. I put it in the freezer last night and it went in with only some effort. This bushing I have only ever mentioned when talking about 5 speeds, so I'm about to find out if there is a reason for that.
 

[Zed Head]

Did you try it on the slip yoke first?  Just curious.  Looks like a good bushing, meant for the job.  Did you put the hole at the bottom?

And, could you post a picture with the bushing in?  Then we'll have before and after for any future visitors.  Even better, if you have the time and patience, a another video showing proper yoke/bushing play.  Good luck.

[DuckManNK]

25 minutes ago, Zed Head said:

Did you try it on the slip yoke first?  Just curious.  Looks like a good bushing, meant for the job.  Did you put the hole at the bottom?

And, could you post a picture with the bushing in?  Then we'll have before and after for any future visitors.  Even better, if you have the time and patience, a another video showing proper yoke/bushing play.  Good luck.

I tried it on the slip yoke and there was very little movement. I installed it with the hole at the bottom since I saw there was another channel up there. Woops?
I went out for a quick drive on the highway got back and no leaks. Before I would park it and immediately would see drips coming from at least half the length of the propeller shaft tunnel.