Zx 5 speed rebuild

[Patcon]

Excellent! We'll try that

Any recommendations on how to torque the shaft nuts? Nissan had a special adapter tool

[EuroDat]

1 hour ago, Patcon said:

Excellent! We'll try that

Any recommendations on how to torque the shaft nuts? Nissan had a special adapter tool

You can do a couple things.

1. Make a tool out of a ring spanner and weld a nut on the spanner shaft at 100mm from the centre of the ring. Use a tension wrench on that. There is a formula to calculate the required torque, but if you use a wrench whereyou dial in the NM, just reduce it by 10%

2. What I do is use a ring-open end combination spanner. Measured the distance to from center of shaft to a position on the spanner where I could attach a bucket to.

Calculate the required wieight. Spec is 14 to 17kg/mtr with tool. If you use a spanner direct on the shaft nut, than add 10% (15.4 to 18.7). If the spanner is 500mm long than calculate 1000mm ÷ 500 = 2.

2 x 15.4 = 30.8kg en 2 x 18.7 = 37.4kg. Fill a bucket with what ever you can find to make 31kg to 37kg. The weight of the spanner won't make much difference and you have a fairly wide tolerance of 6 kg in this example.

[Jeff Berk]

I purchased a 1 1/2 inch crowsfoot wrench and attached it to my 1/2-inch torque wrench so that it was at right angles. This did not change the length of the torque wrench appreciably so the torque value I dialed in should be somewhat accurate. Maybe a little underestimating the torque if you consider the length from the center of the nut to the handle is slightly longer than the center of the wrench head to the handle. Lets see Pythagorean Theorem, a2+b2=c2, a 2 + b 2 = c 2 , can be used to find the length of any side of a right triangle.

Edited May 9, 2021 by Jeff Berk
Picture added because description was confusing.

[Patcon]

I just ordered a 38mm crow foot like that. That's a good idea on setting 90d's

[pogden]

+1 on the 38mm / 1.5in crowfoot cocked 90deg to the side. It's not exact, but if you shoot for the middle of the torque range you will be fine. 

My gears were lined up just like yours are. In one of the how-to videos I watched it was said that they lined up perfectly, which mine obviously didn't. When I looked at them closely, it seemed that flipping the countershaft gear might make things better, so I did that. It was a pain - the woodruff keys kept wanting to fall out - but I did it. Mine was definitely NOT flipped to begin with, but my transmission had definitely been half-assed rebuilt at one point so I wasn't really confident that it was assembled right. After looking at lots of pictures and diagrams, I decided that the the countershaft gear was originally was indeed right, so I put it back.

As @EuroDat said, once you secure the mainshaft bearing to the front housing with the big circlip and make sure you have the right countershaft bearing shims in place, everything lines up pretty well. It's still not perfect, but it's good. 

As an aside, the reason I rebuild my WR 5-speed was that it sometimes slipped out of 2nd gear. I actually never drove it much (maybe 20 miles) before the engine and transmission came out for other reasons, but it slipped out of 2nd a few times so I decided to learn about transmissions while the engine was being worked on. Sadly ... it still slips out of 2nd (rarely) and 4th (occasionally, when I rap it out in 3rd then drop it into 4th and coast). I had thought the problem was probably due to worn detent balls/springs (which I replaced) or worn baulk rings (which I also replaced), but apparently there's something else that causes the problem. I did look carefully at the 1-2 and 3-4 selector rods and forks and they looked fine (to my untrained eye). Otherwise, the transmission shifts great and it "feels" really good. 

[Patcon]

28 minutes ago, pogden said:

+1 on the 38mm / 1.5in crowfoot cocked 90deg to the side. It's not exact, but if you shoot for the middle of the torque range you will be fine. 

My gears were lined up just like yours are. In one of the how-to videos I watched it was said that they lined up perfectly, which mine obviously didn't. When I looked at them closely, it seemed that flipping the countershaft gear might make things better, so I did that. It was a pain - the woodruff keys kept wanting to fall out - but I did it. Mine was definitely NOT flipped to begin with, but my transmission had definitely been half-assed rebuilt at one point so I wasn't really confident that it was assembled right. After looking at lots of pictures and diagrams, I decided that the the countershaft gear was originally was indeed right, so I put it back.

As @EuroDat said, once you secure the mainshaft bearing to the front housing with the big circlip and make sure you have the right countershaft bearing shims in place, everything lines up pretty well. It's still not perfect, but it's good. 

As an aside, the reason I rebuild my WR 5-speed was that it sometimes slipped out of 2nd gear. I actually never drove it much (maybe 20 miles) before the engine and transmission came out for other reasons, but it slipped out of 2nd a few times so I decided to learn about transmissions while the engine was being worked on. Sadly ... it still slips out of 2nd (rarely) and 4th (occasionally, when I rap it out in 3rd then drop it into 4th and coast). I had thought the problem was probably due to worn detent balls/springs (which I replaced) or worn baulk rings (which I also replaced), but apparently there's something else that causes the problem. I did look carefully at the 1-2 and 3-4 selector rods and forks and they looked fine (to my untrained eye). Otherwise, the transmission shifts great and it "feels" really good. 

Thanks for that reply. Very helpful

[Jeff Berk]

Could the slipping out of gear be related to a damaged shifting insert spring? That was a suggestion a mechanic gave me when I was having problems with 5th gear.

On a side question... What is a reasonable price for a 5-speed that is sold as is with minimal opportunity to inspect it? I have someone who is considering buying a junked car and offering me the transmission if I throw in some money for the car. I'm not sure if there is an opportunity to pull the transmission first.

[Patcon]

I think anything in the $2-300 range is good

[pogden]

Could the slipping out of gear be related to a damaged shifting insert spring? That was a suggestion a mechanic gave me when I was having problems with 5th gear.

I replaced the insert springs with new ones, but the inserts are NLA. I looked carefully at the springs and inserts from both the 1-2 and the 3-4 synchro hubs and they seemed fine. But I replaced the springs anyway.

Sent from my KB2005 using Tapatalk

[Patcon]

I replaced those springs too. We'll see how it changes the shifter feel

[Patcon]

So I did some measuring

Current gear offset is .112 (2.84mm)

With the case on and the shaft down as far as it will go the projection into the bellhousing is .110 (2.79mm)

With it pulled forward for the snap ring the projection is .195 (4.95mm)

The difference is .085 (2.16mm) so the gear offset appears to be .027 (0.69mm)?

[Patcon]

So we have most of the tranny reassembled.

We are working on the cases. I have two O rings for the shifter. One is easy to replace

The one on the OD there. But I suspect there is one internally as well. Should I drive out the rear cap that is staked?

Also is there any particular way to orient the new Omega bushing? It has a hole but I didn't know if there was a specific orientation because the existing one didn't have a hole

@EuroDat