Gearbox Rant

Hi,

Just wanted to have a rant about the gearbox and share my pain with everyone.

I know I own a D21 and this was to be expected, but yesterday on the way home from our Easter long weekend adventure the gearbox went in the nav. The old girl made it to just over 400, 000.

for the last month or so the gearbox had been making a whirring noise, which I put down to thrust bearing (oil etc was fine and sounded like my other cars thrust bearing issue). On the way home yesterday, about 70km from home the nav went crunch and started shuddering with loud crunching noises in 5th.

After pulling over and doing some testing, we found every gear except 4th was making a horrible nose and shuddering while driving.

so drove home in 4th, everything was ok there. but it looks like I'm up for some more DIY repairs on the old nav.

depending on the weather over the next week I should be able to drop the box, pull it apart and see what went wrong.

found a rebuild kit on eBay, $375ish - might be the way to go. otherwise ill be in the market for a gearbox/wrecking Navarra.

Cheers for reading

That's a bummer, but 400,000km is a bloody good run. I can only hope that I can reach those sort of km without issues in mine.

$375 isnt bad for a rebuild kit either probably no gears with that but i recon you will be able to get after market gears prety cheep

That's no good. But as you've said, it's something you expect every time you drive it with 200,000km+. Hope all the gears are okay. They're the expensive part. Make sure you set your clearances properly so you don't have to pull it out again.

wouldnt it be cheaper to visit the wreckers...mine keeps jumping to neutral from 1st and 3rd when i rev bit hard or when climbing up a hill not all the time but it does that

YALA said:

wouldnt it be cheaper to visit the wreckers...mine keeps jumping to neutral from 1st and 3rd when i rev bit hard or when climbing up a hill not all the time but it does that

Click to expand...

My Terrano jumps out of first on deceleration. Not too big an issue
My old Dual cab was jumping out of third on deceleration and that reallllly sucked

Mine's going the same way - whines on every gear except 4th, and has done for 18 months, but it's still going.

I chased around a secondhand gearbox from wreckers - generally wanted $800 plus, but none available at the time.

Pinelli said:

I chased around a secondhand gearbox from wreckers - generally wanted $800 plus, but none available at the time.

Click to expand...

That's a pretty bad investment since the second hand one will die itself shortly after.

mine was coming out of 5th on the freeway if i backedd off the throttle a bit. in 4wd it would jump out of any gear when i backed off...thats was anoying as all hell. just meant leaving the right foot down guy i bought a wreck off said there was somehting you could adjust to stop that and it was pretty easy, i never looked into it, nfi if he was talking the truth or not.

yeah, I wont be getting one from a wreckers, if mine is not just bearings (missing teeth etc) ill just go buy a d21 wreck and sell the parts i dont need.

The last d21 shitter i bought was a ute, found it for a mates farm. 4wd, ute, 2.4 petrol, unregesterd runs sweet $400

time before that was a terrano, turbo diesel whole car minus an alternator? was $450. smashed the turbo motor in my nav and sold off everything else. in hindsight i wish id kept the manual gearbox, but i got offerd a pretty penny for it, so i sold it.

im sure something will wander my way pretty cheap, it allways seems to happen.

cheers for all the coments guys, im not overly concernd about it, i know whats involved with taking the gearbox out (done for a mate and when i wrecked the terrano) so im not looking forward to it but luckly i have pleanty of time.

- christian

unkn0wn said:

guy i bought a wreck off said there was somehting you could adjust to stop that and it was pretty easy, i never looked into it, nfi if he was talking the truth or not.

Click to expand...

When I had mine rebuilt, when I got it back it started jumping out of fifth on overrun (it hadn't done that prior to rebuild). I took it back to the gearbox place and they jammed a bigger ball bearing or something in the retaining catch for the shifter fork. Made it hard to get into reverse, but stopped the jumping out.

Dion said:

That's a pretty bad investment since the second hand one will die itself shortly after.

Click to expand...

Yeah, that's what I thought. I ended up with a wrecked Terrano for about the same price, with the turbo diesel, and good seats as well

I've got the gearbox and engine out. Someday I'll actually get around to putting them in the Nav.

Well,

I did what i should not have done and bought a second-hand gearbox. After pulling it all apart for the bell housing swap, I found out it was not a 'good working' gearbox as advertised.

Anyway, pulling off the bell housing showed what my orgional gearbox failed from. Pardon my ignorance on the correct part names, but the lower race of gears has a bearing midway up the gearbox. this is missing half its balls and causing the shaft to wobble all around.





I should have just got a new bearing to replace this, but i went and got a junker gearbox.

1st issue was the smashed input shaft cover, no biggie, mine is fine

2nd issue behind that is the main input shaft bearings are mostly gone



this made getting the bellhousing off a major PITA. had to use some brut force and destroy that bearing race compleatly.



decided i could use the input shaft from my box on the junker, as the insides seem fine.

anyway to the important part, as per nissan manual i need to disconect this 'striking' arm before the rest of the box comes apart. can anyone tell me how to do this, the manual is vague and just shows somone hitting it with a hammer?



hopefully once i have that out i can do everything I need to do to get a working gearbox.

lastly, here is a pic of my mate trying to clean it at the carwash (suprisingly the carwash employee let us do this, he even watched and offerd advice)

^ Lol. I am sure the EPA would love to see that.

thought it was time for an update.

I have been using my roomates car while he was overseas so I have not really rushed into fixing the navara.

I managed to get the junker gearbox apart using magic. I didn't know how i did it until recently.

To remove the striking arm you need to put it in 5th gear.
then pull the housing forward slightly,
then push the gear stick connector further toward 5th.
the striking rod should come out of the gear change levers.
then you can pull the assembly out of the casing.
If you get a torch in there you can just see what your doing, its a little fiddly, but its easy enough once you know what your doing.

I took the centre assembly (gearings and gear-sets) to a gearbox person.
he convinced me to have all the bearings replaced, instead of just the front one.
anyway he did that an charged me $400.

This weekend we tried to put it all together.
had an issue with the bell-housing drain plug, from before where it was rounded out, so you couldn't undo it.
after trying to drill a ex-y out into it we welded a bolt into it. that snaped. we ended up welding a wheel nut to it and heating it up a bit, before it came out - that wasted allot of time...

went to put the gearbox back together and the rear main bearing was larger...wtf...so they guy who rebuilt it used the wrong bearing. So going back there this week to get him to correct his mistakes....waste of time there...

took my original gearbox out of the casing, after i worked out the trick to it.
turns out, it was not just the centre bearing that went. The rear main bearing went to, and some of the teeth on the 5th gear cog were chipped/missing. So I did need the 2nd box after all (this made me fell a bit better).

oh well, certainly a learning experience!

Old gearbox, missing half of some of the teeth



new setup with new front cover gasket and seal.



close-up front of the internals



closeup of the rear

lets get this party started



wouldn't be home mechanics without some blood.



bitch is back together. one bell-housing/gearbox bolt ate the thread without applying torque.

Looks like there was some old gasket goo inside the bell-housing thread. that's the crap thing about alloy, the threads don't take well to any kind of dirt or over torque.

Its all together without this bolt, but i have an idea of how to fix it, just required grinding. Will give it a go this-afternoon. Was not to keen on firing up the AG last night and getting complaints from the neighbours.



front cover, waiting on new thrust bearing to arrive from nissan



Once near thrust bearing is here ill try and put her back in the car!

next nights progress.

Turns out the speed-o sensor thing is missing from the gearbox going in and the old gearbox its broken off halfway in, so its useless to me.

speed-o cable is broken anyway, so i made a plate to cover the hole so no oil comes out (ive been using a GPS for speed pretty much since i got the Navara)

I gently attacked the area of the bell-housing that had the thread in it. A whole heap of gunk came out of it, including lots of old red gasket goo. How i diffident see that when the bell housing was off, i don't know.

it looked something like this (pics turned out shit)



I did not want to push my luck and go much further than the hole. In doing this i needed to downsize from the standard M8 size to M6+ washers, as to fit the M8 nut in i would have needed to grind away some more and as I said, im not pushing my luck with this Gbox..

anyway, end result



double nutted



now we wait for a thrust bearing to arrive.....

Nice work! Keep up the updates.

Thats one way to fix it, I dont know if i would of been game enough to do what you,ve done. But it seems ok looking at it, desperate times call for desperate measures