Unknown quantity - advice required

Rob Gaskin

Treasurer
Staff member
Site Administrator
Haven't had a chance to look at a place yet that would be able to repair the reverse gear, locally would be ideal, thinking smoothing it out might be the best option. My hesitance is smoothing it out too much and then finding it's useless. I assume the mechanical lockout consideration is because reverse is too easy to engage whilst driving?

Yes I found reverse too many times when in a hurry (one was my only time at santa pod).

Reverse gear - I think you just need to make sure that the gears can slide together. Reverse is the only gears where the actual gear - wheel moves into engagement.
 

Albrecht

Well-Known Forum User
I think the reverse gear is especially vulnerable to being inadvertently 'touched' when shifting down out of 5th. All too easy to go just a tiny bit too far.

Reverse is a 'straight cut' (not helical) gear, so it 'resists' engagement (A Good Thing too!) to the detriment of its teeth. Also suffers from overly hasty shifts into reverse with characteristic 'crunch' sound effects and shrapnel which hopefully gets picked up by the drain plug magnet...
 

Geoff-R

Club Member
This counter shaft bearing is going to be interesting to get off. Just removed the lock nut, I don't know what opinions are on reusing these. Technically it can be done but logically I'm thinking it's best practice to get a new one. Is this something Nissan can still obtain? If so does anyone happen to know the part number or how I can find that out? I don't fancy having a 30 min run round with their parts department!
 

Geoff-R

Club Member
Just for info called the local dealer and those counter shaft nuts only come in a pack of 10 and they're £16.51 each, I suspect, back in the day a pack of 10 would be what they came in as dealers would have held stock and used as and when. I think best course of action is to re-use that nut.
 

Geoff-R

Club Member
So I'm currently putting the box back together after sorting the bearings and sourcing a new reverse idler gear from the states. Front of the transmission is on but I'm having a right time putting the rear casing on with the selector forks. I'm reading the transmission manual but it takes a bit of understanding with regards to the position of the forks and the gear selector rod when putting it back together. At present my forks are as below but the when the box goes back together I have no movement of the gear lever so I know I'm doing something wrong. Can anyone who's put this back together before put me out of my misery before I lose my marbles? Thanks.
 

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zbloke

Club Member
Your selector forks all look to be in the correct positions, you could try moving the 'striking rod' further to the side of the gearbox casing and try again

I went through this about 18 months ago and it was a bit fiddly to get it all to line up, as you're getting close to having the casings touch wiggling the housing the gear lever sits in to get the 'striking rod' to engage with the selector forks seemed to do it for me
 

Geoff-R

Club Member
Just gave it another crack this morning with this tip, think I was just tired yesterday and being a bit naive thinking it just slotted on. Just popped the back on now with a bit of wiggling and think I've engaged the gear selector fork with the other forks as I've managed to engage first, second, fifth and reverse. Struggling to get in to third and fourth but then I haven't bolted the rear casing on yet. My only issue is I did a dry run after cleaning all the sealant off so going to have to pull it back off to put sealant on. At least I know it goes back together now.
 

Geoff-R

Club Member
Got the rear case on which was great, however, can't select gears with the detent bearings and springs in place and torqued up. If I loosen them it's fine, I can select all the gears which is great but it's not a fix. I'm wondering if the springs are out of spec or the ball bearings have worn so that there is too much friction on the rods to allow smooth operation. Is there a UK supplier of these? I'm guessing it's a NLA part from Nissan now?
 

zbloke

Club Member
Did you completely remove any/all of the detent balls and springs from the centre plate while you've been carrying out the repairs?

And have you got the box firmly secured to a stand/fixture or has it been loose on the bench/floor while you've been trying to select gears with the detent retainer screws tight?
 

Geoff-R

Club Member
Did you completely remove any/all of the detent balls and springs from the centre plate while you've been carrying out the repairs?

And have you got the box firmly secured to a stand/fixture or has it been loose on the bench/floor while you've been trying to select gears with the detent retainer screws tight?

Removed all of the bolts which retained the springs and check balls. In hindsight I probably didn't need to but wanted to be sure I could select gears by hand before putting it back together. Kept all of the check balls and springs but they look a bit worn like the end of the spring has been pushed out. This is how they came out.

For the time being the box has been on the floor for assembly, lowered in to the bellhousing which is raised off the floor so there is clearance for the main shaft. I've not put it on the bench yet with the detent retainer screws tight.
 

zbloke

Club Member
Ok, when I did my box I found moving the gear lever fore and aft, against the detent spring/balls, difficult but doable, having it on a bench with an assistant doing their best to hold the box securely while I checked for it going into each gear did help

The detents do need to be quite tight in operation for them to work effectively
 

Geoff-R

Club Member
I'll try it up on a bench but on the floor it just feels like I have to put way too much pressure on the gear stick and there is zero movement. I've read it can be a bit of a goldilocks situation, too tight and you can't move the gear stick, too loose and it will pop out of gear.
 
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