Rb25det Gearbox Crunching Into 4th Gear

[woolls]

those clips are from the sliding hub that selects gears. 3rd and 4th are f**ked. box has to come out, remove the bell housing, remove the input shaft from the mainshaft and you will find that the sliding hub outside part will just fall off

On A 25 box, you can not get the input shaft off with out totaly stripping the box IE, removing reverse gear and overdrive. Once thaey are removed, the main shaft and cluster has to be pushed out of the centre plate at the same time. Then input shaft and 4th synchro will come away from the main shaft. You then need to remove a C clip on the main shaft to allow you to remove the 3rd and 4th synchro hub.

[Guilt-Toy]

On A 25 box, you can not get the input shaft off with out totaly stripping the box IE, removing reverse gear and overdrive. Once thaey are removed, the main shaft and cluster has to be pushed out of the centre plate at the same time. Then input shaft and 4th synchro will come away from the main shaft. You then need to remove a C clip on the main shaft to allow you to remove the 3rd and 4th synchro hub.

so can we replace this clip and fix this issue? what is the part number for this clip?

more info needed

[Guilt-Toy]

yes no maybe i dont care?

[woolls]

yes no maybe i dont care?

Hope the PM I have sent you, helps you out.

[msnismo]

those clips are from the sliding hub that selects gears. 3rd and 4th are f**ked. box has to come out, remove the bell housing, remove the input shaft from the mainshaft and you will find that the sliding hub outside part will just fall off

Yep thats what Dave just confirmed... mine went in my standard box ages ago!!

Detent clip or something like that... the circled item in the nissan fast diagram is the right part you would need to get Dave has just said (32608+B)

[snozzle]

can this be clarified any further guys? id like to fix this on my car too, taking the bell housing off isnt a big job for me if its gonna fix my stupid 4th gear crunch at high speed

[turboedsloth]

your gona need a bearing press and a few other workshop tools to get to the hub. if you get yourself a manual also it might help out

[snozzle]

i called nissan, they quoted me on 3 things for the 4th gear syncro

Baulk ring 4th $157.60

Syncroniser

Hub + keys $249.85

Sleeve $140.00

Front main shaft bearing $177

He also said i need this other bush or bearing or sumthing if im doing the front main shaft bearing for $56.83

i also called up a tranny guy i know and he told me he can swap the 4th gear syncro over relatively easily coz its apart of the input shaft, told me to just strip it down the gearset and bring it down and he will tell me exactly wats wrong, he said it could even be a worn bearing thats causing the syncro to move about etc

i hope this helps sumbody, i think ill just end up changing that 4th syncro, coz the rest of my box is perfect

[SirRacer]

dont know if these will be of any help to this situation, but they will to someone eventually

[Guilt-Toy]

Okay i sent a PM to turboedsloth because he seemed like he knew what the problem was from his post.

Not only did he give me the info i needed but he gave me pictures and instructions on how to strip the box.

Very nice guy indeed! So thankyou very much turboedsloth!!!

I have converted the pictures and will post them up now.

Now all we need is the part number for the clip / clips and we can start repairing our box's!!!!

Took me a while to copy all the files from the doc file to jpg files and add the info in the next post but its good to get this info on SAU and out there so this issue can be repaired by anyone in the future.

So thanks again Turbodsloth you are a champion!!!! (everyone needs to thank him if this has helped you)

Now all we need to do is confirm the part number. Maybe Dave can confirm this for us.

[Guilt-Toy]

Selector Hub Clip Instructions (Thanks to turboedsloth)

1.Box on the Bench

2: 2. Remove electrical connectors, speedo, case bolts and selector cover. There is a spring under the cover once you pull it off

3. Spring under selector cover in position, knock out selector pin

4. Remove front cover in bell housing and remove input shaft bearing ring and also very top circlip and spacer looking thing

5. Remove selector rod intent and spring, there is a ball behind it as pictured, it will more than likely fall into the case

6. Split the cases and your left with something like this. Remove the breather hose aswell

7. remove bolt, then that selector shaft can be removed

8. Knock pin through, then main selector rod can be removed aswell as forks

9. knock pin through and remove bolt then pull selector and rod out

10. Remove circlip, retainer, split washer under retainer and bearing, place inline on bench

11. Remove cluster circlip and bearing

12. Remove reverse idler gear and brass washers, place together on bench

13. Use puller or hammer an drift (don’t be rough or it’ll break) and remove hub and gear

14. Use puller to remove 5th gear on cluster

15. Remove retaining plate

16. Use puller to remove bearing race, speedo gear and 5th gear

17. Once the gears are removed using a rubber mallet or copper hammer remove mainshaft and cluster out of centre plate. This will make both shafts fall out

18. Once the shafts are out you can get to 3rd and 4th gear selector hub where those clips you found in your oil originated from.

When you come to put the unit back together make sure there is a tiny bit of clearance between the selector rings and gears and also put a drop of ATF oil or thin gear oil on the surfaces.

Then its just a matter of following these photos on reverse. I like to put locktite on the retaining plate bolts and the selector rod bolt just in case.

[woolls]

Selector Hub Clip Instructions (Thanks to turboedsloth)

1.Box on the Bench

2: 2. Remove electrical connectors, speedo, case bolts and selector cover. There is a spring under the cover once you pull it off

3. Spring under selector cover in position, knock out selector pin

4. Remove front cover in bell housing and remove input shaft bearing ring and also very top circlip and spacer looking thing

5. Remove selector rod intent and spring, there is a ball behind it as pictured, it will more than likely fall into the case

6. Split the cases and your left with something like this. Remove the breather hose aswell

7. remove bolt, then that selector shaft can be removed

8. Knock pin through, then main selector rod can be removed aswell as forks

9. knock pin through and remove bolt then pull selector and rod out

10. Remove circlip, retainer, split washer under retainer and bearing, place inline on bench

11. Remove cluster circlip and bearing

12. Remove reverse idler gear and brass washers, place together on bench

13. Use puller or hammer an drift (don’t be rough or it’ll break) and remove hub and gear

14. Use puller to remove 5th gear on cluster

15. Remove retaining plate

16. Use puller to remove bearing race, speedo gear and 5th gear

17. Once the gears are removed using a rubber mallet or copper hammer remove mainshaft and cluster out of centre plate. This will make both shafts fall out

18. Once the shafts are out you can get to 3rd and 4th gear selector hub where those clips you found in your oil originated from.

When you come to put the unit back together make sure there is a tiny bit of clearance between the selector rings and gears and also put a drop of ATF oil or thin gear oil on the surfaces.

Then its just a matter of following these photos on reverse. I like to put locktite on the retaining plate bolts and the selector rod bolt just in case.

This may be of some use

http://www.300zx-twinturbo.com/cgi-bin/manual.cgi

[Guilt-Toy]

Yes.. finally we are getting traction in this thread!

Any more info will be good.. when i get the bits il be putting some more pics and info up.

[Swiper the Fox]

3 x $10 for your bits...they had them in stock.

your address please.

[Guilt-Toy]

i need 9 of them

3 x $10 for your bits...they had them in stock.

your address please.

[snozzle]

top work guys!

quick question though; is much further work needed to actually change the 4th gear syncro along with these clips ???

and sorry if i misssed it but do you guys have any part numbers yet for those clips?

cheers

[turboedsloth]

once you've gotten it all apart and the input shaft has fallen off the front you'll find a c clip on the mainshaft, remove this and the whole selector hub should either fall off or it may need a tiny bit of pressure behind it to slide it off. Then its only a matter of marking the hub to make sure the slider is put back on the same way, remove the old clips, install new ones then put it all back together in the reverse of the instructions.

[snozzle]

thanks champ! thanks to everyone else too, will keep this page on favourites for a rainy day

[Guilt-Toy]

heading out to do this to my box now.

[skyguy61]

Hey Guilt Toy,

Did you get around to doing the overhaul yet? if so how did it go and what parts, gaskets etc did you use, cheers