Author Topic: 4WD drivetrain. What goes wrong with these?  (Read 2306 times)

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Hopeless

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #15 on: 06 June, 2017, 08:49:55 PM »
I'm not sure about the 4WD P10s, but the FWD P10 autos switched from mechanical to electronic control at some point. FWD and 4WD trannys aren't interchangeable because the centre diff is in the tranny, and the way it outputs to the transfer case means the trans housing is different. You might be able to change the internal from a working FWD trans into yours though?

Right so a bit of google searching has reminded me that most P11 auto's were CVT. Mine is definately not A CVT. It's a plain jane automatic. The bloke from whom I bought it replaced the clutches on reverse, and on low gear. (I saw it on his bench in bits)

Does that increase the likelyhood that the gear out of a P10 would be the same? Given the new clutches/oil/flushed out innards I'd prefer to slam the bits from another front into mine. I guess I'll have to get the whore out and apart to see which bit has failed.

Next question is does anyone know what the final drive ratio is on these things? Or have a link to find it?

Brotangp104lyf

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #16 on: 07 June, 2017, 03:36:05 AM »
I'm not sure about the 4WD P10s, but the FWD P10 autos switched from mechanical to electronic control at some point. FWD and 4WD trannys aren't interchangeable because the centre diff is in the tranny, and the way it outputs to the transfer case means the trans housing is different. You might be able to change the internal from a working FWD trans into yours though?

Right so a bit of google searching has reminded me that most P11 auto's were CVT. Mine is definately not A CVT. It's a plain jane automatic. The bloke from whom I bought it replaced the clutches on reverse, and on low gear. (I saw it on his bench in bits)

Does that increase the likelyhood that the gear out of a P10 would be the same? Given the new clutches/oil/flushed out innards I'd prefer to slam the bits from another front into mine. I guess I'll have to get the whore out and apart to see which bit has failed.

Next question is does anyone know what the final drive ratio is on these things? Or have a link to find it?
On mine the last two numbers relate to final ratio. 38 is 3.8 and others 42 or 4.2 I think from memory. Mine had the long box originally until swapped out for gti pulsar one. 1000rpm difference at 100km in top cog so quite a big difference on the road.

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Hopeless

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #17 on: 07 June, 2017, 06:22:14 AM »
Being 4wd the ratio is critical.
I had a sub once where the front and rear were different ratios. It created many a ball ache.

Is that number you speak of in the body tag?

Brotangp104lyf

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #18 on: 07 June, 2017, 06:35:05 AM »
Yeah its the last digits on the trans no. On the tag. Provided of course its an original box in your car. And even non 4wd I was shocked there was that much difference. As for markings on the actual box I found nothing conclusive and assumed the tag and box from donor was correct.

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Brotangp104lyf

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #19 on: 07 June, 2017, 06:45:57 AM »
A friend of mine recently picked up a salut wagon with factory det so ive been doing a lil digging around forums on them. From what I've read and seen on his one looks like a bitch but I was blessed with hands small enough to get into nearly anywhere. You might find thru a quick Google that say all 9?-0? 4wd models had ( this ) box with said ratio. I looked into gboxes for the bro but got to " no simple manual swap" ahhh keep it as is till something goes wrong was the end of that tho.

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Hopeless

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #20 on: 07 June, 2017, 12:21:58 PM »
Thanks man.
I'll take a geez at the tag tonight. Then hit up the seller of the p10 unit. Google hates me as much as I hate it, and as such I never seem to be able to hit the right search to find what I need. It sucks that fb has sucked so much traffic out of the forums. Forums are the most helpful.

Brotangp104lyf

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #21 on: 07 June, 2017, 02:47:52 PM »
I suggest becoming a paid member of nzppc as there are a lot of hidden build forums apparently. I've been meaning to but I'm a town once a month guy lol. The g20 forums cab be handy I've found.

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scribble

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #22 on: 12 June, 2017, 08:34:32 PM »
Due to the way Nissan designed the ATESSA 4wd system (different to the Subaru) the final gear (FG) ratio on the tag doesn't matter, meaning you don't have to get the exact same number, it'll just change the overall gearing the same as a FWD box would

This is because the diff in the box is actually the centre diff and the transfer case has the front diff, so the FG ratio is  the centre diff and it then drives both the front and rear diffs.  As far as is known all front diffs in the transfer case are always the same ratio (since there is no reason to change them), but the best solution is to just reuse your transfer case, that way the front / rear diff ratios will be the same.

Brotangp104lyf

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #23 on: 13 June, 2017, 06:01:24 AM »
Due to the way Nissan designed the ATESSA 4wd system (different to the Subaru) the final gear (FG) ratio on the tag doesn't matter, meaning you don't have to get the exact same number, it'll just change the overall gearing the same as a FWD box would

This is because the diff in the box is actually the centre diff and the transfer case has the front diff, so the FG ratio is  the centre diff and it then drives both the front and rear diffs.  As far as is known all front diffs in the transfer case are always the same ratio (since there is no reason to change them), but the best solution is to just reuse your transfer case, that way the front / rear diff ratios will be the same.
He is thinking about keeping his transfer box and mating another auto box from elsewhere if its even possible ( well I think that's what's being asked) I need to go look at mates one again as to how they come apart but in my memory banks its telling me the transfer box drives off the crown wheel on front diff. If that is a different size gear would that not make the rear try drive into or drag/ bind up gears? I had an old sj410 Suzuki with muds on front and roads on back and off road was sweet in 4wd, on the road shed drive about 20ft and bind up tight asf. You had to reverse back to ease pressure enough to get her back out of 4wd and in to 2. It was 970cc and weighed maybe 600kg. If was 2ltre and 1500 odd kg it would have have thrown alloy and oil everywhere I reckon. I may be wrong, you may be right. Either way I'd make bloody sure it wasnt an problem or could end up a hell of a mess!!!

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Brotangp104lyf

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #24 on: 13 June, 2017, 06:08:18 AM »
I do hear what your saying but I wouldn't take any chances as they're a prick to work on and not cheap either. In all honesty I think Nissans are about as good as it get Japanese wise but east west 4wd layouts are not how its done. I reckon it should be possible to just swap out the box part and leave bell housing and transfer as is.

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scribble

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #25 on: 13 June, 2017, 01:29:53 PM »
Normally in a FWD each axle is connected to each side of the diff in the gearbox
With ATTESA it is the following
The front right axle is connected to the right side of the front diff in the transfer case
The front left axle passes through the centre diff (in the gearbox) and is connected to the left side of the front diff in the transfer case
The front diff unit has a shaft that passes through the centre diff and is connected to the left side of the centre diff in the gearbox
The rear diff is connected via the driveshaft into the transfer case which use a reduction/bevel gear that is connected to the other side of the centre diff
It's that bevel / reduction gear in the transfer case that matches the ratio of the rear diff and because of that there is no reason to change it.  If Nissan wanted longer or shorter final gear ratio's they just change it in the gearbox same as what is done with a FWD car.

There used to be a connection diagram posted on the forums, not sure if it was here or some other forums but this is the closest I could find

http://carphotos.cardomain.com/ride_images/2/4705/3421/24261710031_large.jpg

I think I have the pic somewhere at home so will post it up once I find it since this type of question gets asked often and the diagram makes it plain as day as to the layout.

In the simplest terms, if you think about a FWD car, the front left wheel connects to the left side of the diff in the gearbox and the right wheel to the right.  In the 4wd version the diff in the gearbox drives 2 other diff's instead, so is now called the centre diff.  Most other designs use the transfer case to split the drive, doing it the Nissan way allowed them to keep the part count to the lowest, since the gearbox is just basically just a FWD box with a transfer case bolted to it (although the 4wd box itself is a different casting to the FWD box so aren't interchangeable)

Quote
He is thinking about keeping his transfer box and mating another auto box from elsewhere if its even possible ( well I think that's what's being asked) I need to go look at mates one again as to how they come apart but in my memory banks its telling me the transfer box drives off the crown wheel on front diff. If that is a different size gear would that not make the rear try drive into or drag/ bind up gears?

Yes he can reuse the transfer case with whatever FG gearbox he can find (assuming it's control method matches, mechanical or electronic)


Found the pic in a very old backup
« Last Edit: 14 June, 2017, 05:17:15 PM by scribble »

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #26 on: 13 June, 2017, 09:47:02 PM »
^^^ this is an EXCELLENT description of the layout of the 4WD system. Thanks Scribble!
Kieran: thank you for being amazing... Have my babies.

Hopeless

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #27 on: 03 February, 2018, 10:13:20 PM »
Well I still own this car.
It's been keeping the grass down on my front lawn this whole time.
This weekend a friend has let me use the hoist at his workshop. Another mate came over to lend a hand.
With rereading this whole thread, what I found when I got it up on blocks was that the GONK-GONK-GONK-GONK-GONK-GONK was there when just the front wheels were driving (Handbrake applied tight) regardless of if it was the left, the right, or both wheels spinning. Then with the foot brake on, it made the same noise with either one, or both of the rears spinning too. This leads me to believe the  problem lies where the centre diff takes it's drive from the transmission itself.
I found another trans on trademe. Which wasnt crazy money.
Mate who's hoist I'm using talked me out of of dropping the motor and box. We've unbolted everything we can see. Including that lone bolt tucked down behind the speed sensor. (That was hard to find!)
there's a bit of a split showing. but we cant get the auto to separate fully from the block.
What am I missing?
If I cant get the whore out tomorrow I'll bolt the suspension back up, and dollar reserve it as is.

Hopeless

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #28 on: 06 February, 2018, 01:53:23 PM »
After two.pretty lengthy and arduous sessions we managed to get the old.Trans out, and the new one in and bolted up. I can say with absolute certainly that this was the most difficult car related job I've ever endured. A clutch and gearbox swap on another (north south mounted engine) car I've got is going to be an absolute pleasure by comparison.
There are only two obstacles left.
One, the replacement unit is from a P10, mine is a P11. The three pin plug (electric overdrive?)  Is different. Fortunately  the p10 Trans has a wire coming off Verse the p11 having the plug on the Trans.  So a quick trip to pick a part will yield the parts needed there.
The second hurdle is more off a ball ache. The kick down cable is much shorter on the new Trans. I'm assuming (based on the shorter length) that the p10  must have the TB low  mounted "under" the manifold? As opposed to up top on the P11.
On the hoist it didn't look easy to detach the end of the cable from the inside of the Trans with the pan off. So I'm yet to refill the new Trans with oil untill I decide the best way to make this problem go away.
I never ever ever want to go through an ordeal like that again.

Hopeless

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Re: 4WD drivetrain. What goes wrong with these?
« Reply #29 on: 15 July, 2018, 10:33:55 AM »
Just an update on this thread.
A few weeks ago I finished fixing this car. I brought it home from my friends workshop, (who kindly let me use his hoist over the long Waitangi weekend) and parked it up on the front lawn. After another saga with fixing and finally getting rid of a BMW that I also wished I'd never bought, the Mighty P11 T4 wagon got dragged into the garage. The wiring for the overdrive solenoid/lock up converter solenoid was as simple a chopping the right plug off a P10 at pick a part. And splicing it onto my loom. (Wires were different colours, but with both the trans pans off I could see where the wires needed to go)
But Swapping the P10 kick down cable for the longer P11 one was not such a straight forward operation. A mate who is an auto trans repair man from invercargill sent me some pictures of his repair manual. And I had to drop out the valve body to disconnect the cable from inside the transmission.
I eneded up undoing ALL the bolts on the valve body of the bolt trans. so I could see exactly which bolts to undo to drop it out without seperating the parts of the valve body itself.
got it out, and swapped the cable. Put her all back together. Now its wof and rego, and up for sale on FB. Been up for a week, and so far zero interest. boooo.

If   anyone wants what left of the old 4wd trans hit me up. It has a tooth off where the drive exits the transmission, and goes to the centre diff. It had new clutch discs  fitted to the Low, and reverse clutch packs. (by the previous owner, I saw the trans on his bench when he did it) The valve body is out, but all the there. and so is the torque converter. free to take away if it can help some other poor bastard who's got issues with their T4. Otherwise I'm going to dump it.
This is my last post ever here. Ill never ever own another P car.

Bart.