How to fix hard upshift to 5 gear? Any good shop in NY or NJ ? Or should I try ?

[acuhon]

Thanks Ralph, I ordered all brass rings, synchronizers, gears and couple bearings to start. Those brass rings didn't look bad to me, but I don't know how new looks Thanks to point it out. Now I don't feel bad that I ordered to many parts. I have a press and manual. Right now I'm waiting for parts.

Bense, Thanks for the offer, but I would like to learn how it works. There is very good chance that I'll be pulling the GB out because I forget something, but that is a part of learning.

 

[goldNSX]

The brass ring does look too close to the gear indeed. There should be around 1.0-1.1 mm between the gear and the brass ring if you push the brass ring against the gear. I'd check the new ones if they grab on the gear, best to check with both parts in your hand. Very good video about synchros: https://www.youtube.com/watch?v=MXsRfbOiBhE.

 

[acuhon]

The brass ring does look too close to the gear indeed. There should be around 1.0-1.1 mm between the gear and the brass ring if you push the brass ring against the gear. I'd check the new ones if they grab on the gear, best to check with both parts in your hand. Very good video about synchros: https://www.youtube.com/watch?v=MXsRfbOiBhE.

Very good video about synchros . Thanks. Got some parts to start. What are the most common mistakes with first time GB rebuild?

 

[Bense]

Very good video about synchros . Thanks. Got some parts to start. What are the most common mistakes with first time GB rebuild?
View attachment 143898

Do you have a bearing puller yet?

 

[goldNSX]

Very good video about synchros . Thanks. Got some parts to start. What are the most common mistakes with first time GB rebuild?

Parts look good. Where did you get them from, US or JP? I also see some gears.

What are you going to start with? Doing it the first time by myself and with no help of an assistant (which IS very helpful in some steps esp. while closing the gearbox), I've studied the service manual up and down. I'd work according to it. Taking the shafts apart is easy with the service manual. Just take the parts off (you need a hydraulic press) and put them on the table in the order and in the same orientation you took them off. Place the new parts in the second row next to the one with the old ones and compare the new parts with the old ones 1:1. Putting them back together is where you need to pay attention:
- orientation of the hub/sleeves 13-23, small round pictures (I've the 1991 service manual), 13-29, also read 13-36: there are two longer teeths in the synchro hub, every 120 degrees which have to be matched the deeper grooves in the sleeve.
- orientation of some bearings
- pay extra attention to the synchro of the 2nd gear esp. when you press on 3rd gear. I used to check if the 2nd gear still turns freely while pressing the 3rd gear on. If 2nd gears gets resistance or even gets blocked STOP pressing 3rd gear and check again. See my UK thread.
- the big nut of the countershaft opens clockwise, not counterclockwise (an exception of the rule).

I don't know your level of skills or if you have worked on the gearbox before but I guess your skills are higher than mine. Just let me know if I go too much into details.

As soon as you've completed the mainshaft and the differential (are you doing to work on that?) you can take care of the shims you might have to order extra...

 

[Bense]

the brass blocker rings in your pictures are shot,some are bottomed on the gears ,losing their locking ability . some people call them synchos ,they are not ,they are a part of the synchronizer assy.Their purpose is to allow two different rpm events to couple without a clash. They work as a brake on one component and as the same time to speed up another component to allow mesh ,they are designed to be the wear part. I would suggest you look at articles on how a constant mesh synchronized tranny works . Take your time but you must have access to a manual , certain tools and a press{depending how deep you get into this} . You will also be replacing many bearings

I thought they were called scalps?? :tongue:

 

[acuhon]

Parts look good. Where did you get them from, US or JP? I also see some gears.

What are you going to start with? Doing it the first time by myself and with no help of an assistant (which IS very helpful in some steps esp. while closing the gearbox), I've studied the service manual up and down. I'd work according to it. Taking the shafts apart is easy with the service manual. Just take the parts off (you need a hydraulic press) and put them on the table in the order and in the same orientation you took them off. Place the new parts in the second row next to the one with the old ones and compare the new parts with the old ones 1:1. Putting them back together is where you need to pay attention:
- orientation of the hub/sleeves 13-23, small round pictures (I've the 1991 service manual), 13-29, also read 13-36: there are two longer teeths in the synchro hub, every 120 degrees which have to be matched the deeper grooves in the sleeve.
- orientation of some bearings
- pay extra attention to the synchro of the 2nd gear esp. when you press on 3rd gear. I used to check if the 2nd gear still turns freely while pressing the 3rd gear on. If 2nd gears gets resistance or even gets blocked STOP pressing 3rd gear and check again. See my UK thread.
- the big nut of the countershaft opens clockwise, not counterclockwise (an exception of the rule).

I don't know your level of skills or if you have worked on the gearbox before but I guess your skills are higher than mine. Just let me know if I go too much into details.

As soon as you've completed the mainshaft and the differential (are you doing to work on that?) you can take care of the shims you might have to order extra...

Got those parts from JP.
I should rename this tread GB for dummies because that's how I feel sometimes and I didn't even start to put it together. This is my first time I see open GB so please bear with me. My skills when it comes to GB is "0'" so I'm glad the I'm getting some advice. The plan is to replace synchros and gears 3-4-5. I'm not planning to work on differential . I may replace top two bearings on the counter shaft. They are almost perfect, but now is the time to replace them. Gears and synchros 1-2 don't look bad so I may just leave them for now. I wish that I tested the GB better. The previous owner got PPI at a dealer and they mentioned just 5 gear synchro.

 

[goldNSX]

No problem. We're patient. Not changing the synchros of 1-2 would be a missed opportunity as you have the parts laying around and the gearbox open now. Disassembling the mainshaft is very like doing so in the countershaft.
As for the differential. Did you measure the torque before you took the gearbox out? If not you still can measure it but you'll need the diff tools you might be able to borrow somewhere. If the torque is within specs there is be no reason to open it.

 

[acuhon]

No problem. We're patient. Not changing the synchros of 1-2 would be a missed opportunity as you have the parts laying around and the gearbox open now. Disassembling the mainshaft is very like doing so in the countershaft.
As for the differential. Did you measure the torque before you took the gearbox out? If not you still can measure it but you'll need the diff tools you might be able to borrow somewhere. If the torque is within specs there is be no reason to open it.

You are right, I'll replace the 1-2 synchro and second gear to make sure that I don't hate myself for not doing it. Thanks for pushing me the right direction.
I started assembly of the mainshaft, but I don't see the washer 43x56 between 2-3 gear, part 23930-PR8-000 is discontinued. Now I don't think it was there. It's a big washer to loose. I hope that I can get it from JP. I didn't check the torque of the differential. To late now. I just wanted to be able to shift 5 gear. Next time. How is your NSX-R differential?

 

[goldNSX]

I just wanted to be able to shift 5 gear. Next time.

I personally hate doing things twice if I had a chance doing it right the first time.

...wrong info deleted...
After assembling I'd check the gaps according to the manual. Make sure you have positioned the 2nd gear synchro correctly when you press on 3rd gear (countershaft).

You'll only feel a difference with the Type R diff when you drive very spirited (rear sliding, track).

Just a hint: if you supply us with pics we can help better.

EDIT: Sorry wrong info on the washer. I was confused. We were talking about the countershaft frist and then about the mainshaft you started to work on. Please do not mix up different topics in one post. I'm getting older and it has been some months ago when I completed the gearbox.

Do you mean this washer (no. 12):

 

[acuhon]

I personally hate doing things twice if I had a chance doing it right the first time.

...wrong info deleted...
After assembling I'd check the gaps according to the manual. Make sure you have positioned the 2nd gear synchro correctly when you press on 3rd gear (countershaft).

You'll only feel a difference with the Type R diff when you drive very spirited (rear sliding, track).

Just a hint: if you supply us with pics we can help better.

EDIT: Sorry wrong info on the washer. I was confused. We were talking about the countershaft frist and then about the mainshaft you started to work on. Please do not mix up different topics in one post. I'm getting older and it has been some months ago when I completed the gearbox.

Do you mean this washer (no. 12):
View attachment 144008

# 12 is the washer I was looking for. After reading your build I found my answer. Kaz mentioned that new mainshaft didn't have the washer. I hope I got the newer mainshaft. Back to wrenching.

 

[goldNSX]

# 12 is the washer I was looking for. After reading your build I found my answer. Kaz mentioned that new mainshaft didn't have the washer. I hope I got the newer mainshaft. Back to wrenching.

As you have the short gears the mainshaft needed to be changed because the (long) 2nd gear on the old mainshaft is fix and can't be changed. So it's high likely that you don't have the washer if the newer version didn't have it.

Happy wrenching!

 

[acuhon]

Thank you to goldNSX, Larry, Kaz and the many others who helped me with my first transmission rebuild. It works like new:smile: ! Installed EXEDY twin organic clutch. It's about 25% harder to operate, but I need the exercise. Drove only 30 miles on it so I will report later. It grabs very good .

 

[goldNSX]

Glad to hear. Pitfalls?

 

[Bense]

As you have the short gears the mainshaft needed to be changed because the (long) 2nd gear on the old mainshaft is fix and can't be changed. So it's high likely that you don't have the washer if the newer version didn't have it.

Happy wrenching!

What

 

[acuhon]

Glad to hear. Pitfalls?

Thanks to your post I didn't crush any synchros . Also I din't forget release fork. Yes it's in the manual to put it in, but I almost left it on the floor.
I just took my time to replace all hoses replace all axle boots weld baffle on oil pan .... Now I can sell my stock 91 and register this beast. Hope to make it to NSXPO .