Nissan Civilain Gearbox / splitter / oil help

tuggersbmx · Senior Member

Nissan Civilain Gearbox / splitter / oil help

blaze · Guru

rule of thumb is drain will be in the bottom (rhs of picture), the fill point is normally just below half way up the main shaft (fill point as marked 2nd from rhs). I belive the box as shown will only use those 1 points to change gear oil. I have never serviced that box before but of done thousands of boxes over a life time. Try googling a service manual
cheers
blaze

tuggersbmx · Senior Member

Thanks for the response blaze.
So what would the two (fill and drain) holes at the front of the case be for?
Or are all them just for the gear oil?

What Im trying to figure out is should I be putting two different types of oil into each area?

I have the workshop manual already but it does not explain or show the all holes.
It does state how much oil to put in though.

Plus ive heard there is a separate box are to put oil in for the splitter gears?

Cheers

Jaahn · Guru

Hi Mick smile

I had some sheets with that box copied from a manual but have thrown it out now. But the main 5 speed gearbox is the same as a Nissan Patrol about the same years. So the drain points and fill point are the same.

If you cannot find a Civilian manual, then look for a truck one as they are the same. Nissan called them a Cabstar or an Alas or Condor in different markets. I think the model number is a H40. They have other models with different engines and transmissions in the smaller models.

I believe the selector forks come loose on the rail rods and not uncommon to have problems like you have, you can pull the top off the box and look perhaps without taking it out. Very heavy.

Good luck Jaahn

PS another thought about the gear change problems. Check the linkage for wear at the links and pivots. It is long and complex to get from the stick up front to the side of the box down the back. I remember getting some washers and bushes to get the slack out of several relay rods and transfer levers. Might be all it needs. When the slack is too great it is not putting the gear fully in properly. hmm

Look at this diagram(probably yours); https://www.megazip.net/zapchasti-dlya-avtomobilej/nissan/civilian-2083/w40-6148/mgw40-622029/transmission-control-linkage-7841983

You could look further on this site but it will do your head in, be warned !! confuse

-- Edited by Jaahn on Monday 23rd of December 2019 03:15:56 PM

-- Edited by Jaahn on Monday 23rd of December 2019 03:30:47 PM

Rob Driver · Guru

Some gearboxes react differently to different oils. Road ranger gearboxes were a lot smoother in the changes with lighter grades of oil.

Having said that I dont think that oil will be your problem.
I agree with Jaahn above regarding the selector forks as being the first place to look and if that inspection appears ok then my next suspected problem would be a broken or dislodged circlip in the synchro cone and hub or a cracked or broken cone itself.
Unfortunately, if this is the case it will mean the gearbox has to come out.

Regards

Rob

STRETCH ARMSTRONG · Senior Member

Hey tuggersbmx, l dont know that gearbox but from my landcruiser days the gearbox, transfer case and the fairey splitter box all had seperate oil fill and drain points. From what l know of tojo stuff the 5 gear is on a seperate rail and is not as strong 4th gear. If the gear is crunching l would think syncro or gear is gone. Hope you can find someone to help you.

tuggersbmx · Senior Member

Hi Everyone,

So I had a good inspection last night and there is definitely 2 separate rails for the 5 speed and splitter.
Both rails are extremely loose. Even in gear you can pretty much touch the rails and move them side to side to 3-5 cm.

That does not seem right to me?

Or is that how these old boxes / rails were?

The gear stick is also flopping around real bad, even in gear. Its hard to know what gear you are in / find gears a lot of the time.

I might try find some new bushings for the whole rails systems?

Cheers

tuggersbmx · Senior Member

Also Thanks Stretch for the response.

I also believe that there is a separate transfer and gearbox and splitter box with separate oil for each.

Would they all take different types of oil? Or just transmission oil? 75/80w?

Jaahn · Guru

tuggersbmx wrote:
Hi Everyone,
So I had a good inspection last night and there is definitely 2 separate rails for the 5 speed and splitter.
Both rails are extremely loose. Even in gear you can pretty much touch the rails and move them side to side to 3-5 cm.
That does not seem right to me?
Or is that how these old boxes / rails were?
The gear stick is also flopping around real bad, even in gear. Its hard to know what gear you are in / find gears a lot of the time.
I might try find some new bushings for the whole rails systems?
Cheers _________________________________________________________________

Hi Mick :)

What you can see and feel under there, outside the box are the rods and relay levers. They should be better than that but they live in the dirt and mud down there. As I said with my previous buses, I spent a bit of time packing the joints with washers and some new bushes in the worn pivots. You will be amazed how that improves the feel at the stick. And it will quite possibly fix your problem. If the gear is not pulled into mesh fully it will crunch and stuff the syncro as it jumps out or worse. It is possibly incapable of going far enough because of slack in the system. confuse

You can sometimes rebush those simple joints with plastic tube or nylon tube cut up. And put rubber washers on the sides to of the steel washers to get started. If it gets much better then look into some proper materials. The bearing suppliers will have small bushes in metal or proper plastic. Also the rods with the right angle bends, wear in the holes and can be built up with (bronze) welding to full size again. Not really rocket science hmm

The fork rails are inside the box and you cannot see those until you remove the top cover. Do the simpler linkages first. smile

Jaahn

Plenty of joints to get loose !

Transmission control & linkage

-- Edited by Jaahn on Tuesday 24th of December 2019 12:49:45 PM

Aus-Kiwi · Guru

Try adding 1/2 ATF to thin oil out ? If it works ? The oil was too thick !! My TKO600 Tremec, old T5 Tremec had same issues with oil too thick . Some gear boxs use ATF ( auto trans fluid ) with friction modifier . Most Jap boxs use light oil with tight needle bearings . It sounds as said above ? You have selector issues ??