See what you can do on your side and if you struggle, I am willing to help. I have mailed a couple of stuff so far and by sea is quite cheap.Takes 3 months but for the money I think anyone is willing to wait a bit.

Yea, 110km/hr is about 68mph, that sounds about the same as mine, in 4th and 5th gears. I found that after I have the driveshaft fitted with new u-joints/straightend/balanced, most of the vibration goes away. It still leaks though.
The thing is, the output shaft is in the way. If something goes wrong or the yolk doesn't fit you can't hone it. You can't really measure the ID either. So you're screwed and the whole thing has to come out.
I emailed NissanParts.cc to see if the bushing is still available. I can PM you about buying one for me if need be. Thanks.

Also, Peter's bushings don't seem to be showing up anywhere either. Darn.

Hi ang94541
I am glad I am not the only one sitting with this problem. My car doesn't see the freeway that often as it is only driven over weekends. This is the reason why I can't justify the price it is going to cost to get a 5 speed box or even repair this problem on the 4 speed. We have a freeway speed of 120km/h here in South Africa but I can take it max 110km/h and then I can feel the vibration starting to come in.

Another guy here at work told me exactly the same idea you have. Making a tool whereby you can get the old bush out and then pressing in the new one. He also suggested to use a flat piece of wood when hammering in the new bush not to damage it. The one gearbox shop I phoned recommended that I do not follow this procedure as it can damage the bush. Hell, the price they are asking to pull the gearbox, fix the problem, new gearbox oil and put it back in I am definitely not going to use them.Especially with the possibility of damaging my GX manifold when removing the exhaust from the manifold to get space for gearbox removal.

If you really struggle with the bush on your side, I can get one for you here brand new and we can mail it by sea to bring postage down to a very low price. Let me know.

Yea, I have this probem too. I've changed the rear seal several times in the past and they all leak. I also have a vibration problem with the slightest wear on the u-joints. I found that if I grab the yolk, I can wiggle it around in the trans. I later found that the yolk was worn. I measured the diameter in three places along the length, but its worn enough such that you can feel it.
I swapped the yolk with a spare in good or atleast better condition and the fit is better but still has too much slop.

I've made a tool that I can use with a slide hammer to, IN THEORY, remove the bushing while the trans is still bolted together. The problem is I can't seem to find new bushing.
I believe the stock part is Nissan PN 32132-18000 BUSHING, rear extension.

I like Peter's fix, but I'll probably wait until I HAVE to pull the trans for something else and take care of the bushing then.

Here is Peter's write up...
Repair bushing for 56, 56A and 60 series tailhousings

I understand that b110 5sp prices are expenive, but I would pay $1000 - $1200 for a new one from the factory. I think I may make some inquires in ZA for supply of one. Im guessing they are 60 series H pattern?. As for your repair, I think the cheapest option is find a second hand extension housing with the a rear bearing in spec. In OZ a second hand 56 series 4 sp can be had for as little as beer money if not free. Like I said before, I have a couple of spare 56 series 4sp extension housings, you can have for the price of postage. cheers
benny

its hard to get good service in australia these days aswell.

although, over here i bet there would be plenty of members who'd pay $1200 for a "brand new" 5spd if we could get them!

Thanks for the help guys. You know, I am so negative about the service we south africans are getting. A couple of years I took the gearbox in and asked them to completely go through the box and replace all bearings and check that everything is within specs. I was still living with my parents and didn't see the freeway much with the car. Now I find out that this part is worn that was suppose to be checked and fixed. I am so sick of this $hit. I phoned around to find out about maybe replacing with a relatively new 5 speed box. It seems the crazyness with these 5 speeds that are experienced on your side has rolled over to our side. They are plainly crazy with the prices. If I now roughly convert to Aus $ it comes to $1000 to $1200 for a brand new box. and something like $800 to $900 with boxes that are used.

if you cant get a new bush. like benny said another option is to swap your extension housing for one with a bush thats within spec

That the information I was looking for. Thanks Ange. And you also Benny. I needed to get an understanding of what is wrong with the gearbox and also to try and understand what the gearbox place is talking about to fix the problem. It also sounds now to me that the idea they are having to fix this problem is not a long term solution.
The mechanic said that this bushing ANGE was talking about wears out. They then hone it (or something like that) and then get it back to specs again with a sleeve or something.
I am just afraid I pay for this work to be done and it doesn't work. It sounds more to me that the correct way is to disassemble the gearbox to fix it right.

when you slide the slip yoke of your tailshaft into the rear of your gearbox, not only does it match up the splines and slide over
the ouput shaft, it also slides into a bushing thats there to keep it centred and running true.

the bush will look something like this..




benny was spot on. These bushings should last decades, so fixing the cause at the same time is definately the way to go.
To replace the extension housing bush, id expect you might have to split the extension housing from the gearbox and press the old bush out, and a new one in. i could be wrong on that one though

good luck