What is this set of 389 gears and a 720 gear ratio question

[wayno]

I have these gears in my shed, why does it have the "N2" cast into the housing, is it special, or is that just me?

[datzenmike]

Does it have a 10 digit pt. number on it anywhere? H-190? I guess?? Could be from a 510 goon if it has 23 spline axles but I don't think they have N2 on them. A 29 spline would be no older than '80 could be anything up into the 2000s.

[wayno]

There are a couple of numbers cast into the case that are very hard to read. These photos show the number on the ring gear and the 29 spline axle hole.

[datzenmike]

The earliest truck with that ratio was the '80 720.

[wayno]

I'm just trying to find out why this one is differant than the rest I have, it has a number cast into the case that I beleave is, "ND876", and the photo below is another number in the case.

[albyneau]

I have these gears in my shed, why does it have the "N2" cast into the housing, is it special, or is that just me?

 

 

N2 in American markets was sometimes indicative of nodular iron~stronger and more ductile than gray iron. It's darker than gray (no pun intended) iron, and has a ring when struck a bit more like the ring of steel. Gray iron rings more like a dull thud when struck. Invented in the 40's, it's a cheap mod for HD parts requiring no additional tooling/materials handling~ save a slightly altered alloy formula at the foundry(addition of graphite & magnesium). Whether it means the same thing in Datsunese remains a mystery....

 

[wayno]

N2 in American markets was sometimes indicative of nodular iron~stronger and more ductile than gray iron. It's darker than gray (no pun intended) iron, and has a ring when struck a bit more like the ring of steel. Gray iron rings more like a dull thud when struck. Invented in the 40's, it's a cheap mod for HD parts requiring no additional tooling/materials handling~ save a slightly altered alloy formula at the foundry(addition of graphite & magnesium). Whether it means the same thing in Datsunese remains a mystery....

 

 

So this is a cheaper knock-off set of gears? It's what you use when you have nothing else?

[DRIVEN]

I can't speak to yours specifically but to go along with what albyneau said, I think the N might indicate a nodular iron case (higher magnesium content). Ford marked their 9" cases that way on the nodular units. Only available behind high output engines, originals are rare sought after. They are stronger than standard gray iron -- not an inferior knock-off.

 

Of course this is a Nissan product so it might mean absolutely nothing :blink: .

[albyneau]

I can't speak to yours specifically but to go along with what albyneau said, I think the N might indicate a nodular iron case (higher magnesium content). Ford marked their 9" cases that way on the nodular units. Only available behind high output engines, originals are rare sought after. They are stronger than standard gray iron -- not an inferior knock-off.

 

Of course this is a Nissan product so it might mean absolutely nothing :blink: .

 

I know not all 9" N cases had the "N"~ but they did all have two ribs on top of the chunk vs 1 on gray cases. IIRC they also had raised "reinforcements" around the bolt holes~ as Wayno's pic shows on his chunk....

 

[wayno]

I know not all 9" N cases had the "N"~ but they did all have two ribs on top of the chunk vs 1 on gray cases. IIRC they also had raised "reinforcements" around the bolt holes~ as Wayno's pic shows on his chunk....

 

 

I have two sets of 389 gears that have that darker color metal cases, both are made the same except for the "N2" on the one case.

 

My other gear sets are a lighter gray metal from the 520-21 series trucks, and are 437 and 488 gear ratios

And then there is this gear set, I don't know what metal it's made of as it has been painted by the previous owner, it is made the same way that the 389 gear sets are made, but it is a detroit locker with 411 gears I was told.

[DRIVEN]

#1 and #4 look to be iron while #2 and #3 appear to be aluminum. Got a magnet to check 'em?

[wayno]

#1 and #4 look to be iron while #2 and #3 appear to be aluminum. Got a magnet to check 'em?

 

It appears you are correct, the 520-21 gearset cases are aluminum, you got me off my ass to check.:thumbup: :lol:

[Master-O-Turbonics]

the 4.375 3rd member that came stock in my 81 720 4x4 has N1 on the chunk.

[wayno]

I might as well use this thread.

I am wondering what year 720s came with the 3.545 gears?

[ggzilla]

3.545 came in all these, but you want the N2 version

* 720 1982-1983 2WD with Z24

* 200SX 1982-1983 Manual Transmission

* 810 wagon 1981-1982 L24

* Hardbody 1990-1994 2WD KA24 5-speed

* Hardbody 1997 KA24E 2WD manual non-King Cab

* Hardbody 1998-1999 KA24E 2WD manual

 

Why not go with the 3.346?

[datzenmike]

That was available on the 720 with the Mileage Option Z20 motor.

[wayno]

3.545 came in all these, but you want the N2 version

* 720 1982-1983 2WD with Z24

* 200SX 1982-1983 Manual Transmission

* 810 wagon 1981-1982 L24

* Hardbody 1990-1994 2WD KA24 5-speed

* Hardbody 1997 KA24E 2WD manual non-King Cab

* Hardbody 1998-1999 KA24E 2WD manual

 

Why not go with the 3.346?

 

 

I don't know if I could get my 521KC SD25 diesel moving with 3.346s, and I am happy with the 3.545s.

Basicly I am looking for a set of 3.545s for this guy,

http://community.ratsun.net/topic/39770-1964nl320/

as he has 4.88s right now, and his top speed is maybe 60mph, he has a LD20 turbo diesel in his NL320, since it is a lighter truck, I figure that engine will turn 3.545s also, even though it is a smaller engine.

We are just making this stuff up as we go, I have no idea if it will work, but that is what he is asking for, and since I have done it for others before(changed out the side gears), I will help him also if I can.

I will look around tomarrow at the wrecking yards, it seems like I never see 3.545s but once a year, I mostly see 3.89s, or 3.70s, it would be nice if the 3.545s were more common.

Why do I want the N2 version, they are very hard to find with the "N2" on them, I think I have only seen maybe 3 of them ever, and they were all 3.89 geared units.

[Z-train]

 

Basicly I am looking for a set of 3.545s for this guy,

http://community.rat...9770-1964nl320/

as he has 4.88s right now, and his top speed is maybe 60mph, he has a LD20 turbo diesel in his NL320, since it is a lighter truck, I figure that engine will turn 3.545s also, even though it is a smaller engine.

 

This is HIGHLY debateable.I wouldn't go lower(numerically) than 3.89's.

[ggzilla]

Going from 4.88 to 3.54 is like starting out in 3RD gear with the 4.88s ... have you tried that yet?