Gear ratios...

[pope_face]

Alright, so I realized that there was a thread on this below with the Jason Grey info... I didn't know it was stickied in the engine forum, would someone mind stickying it here?

 

My original question was about a list of final drive ratios and transmission ratios... but I suppose I can ask a more specific question now. Does anyone know which differentials can be bolted to a 521 with little to no modifications, or which gears can be directly swapped into a 521 housing?

[datzenmike]

I think, all the 620 rears, from 4.88 down to the 4.11. The 720 gears, 4.375 down to 3.7(something). Stay away from the '82? and up 4X4s, they changed the input spline to put a larger yoke on it.

[pope_face]

Just to clarify, are you referring to the entire differential, or just the gears inside?

[Fineline]

It has been my experience that any H-190 3rd member will fit into any housing wether it be a wagon or a truck. The difference being in two places. Input flange and axle spline count. Trucks have 29 spline axles and wagons have 27. Check out this link for the gear ratios and how to distinguish.

 

http://www.nwde.org/extras/forum/forum_posts.asp?TID=3243&KW=lsd

 

Nissan used the H-190 al the way through the D-21 or hardbody years as well. There were a few differences in those but they will work in your housing. The input flange from a 620 or 720 iron 3rd member is needed as the hardbodies used a larger one. The flange from an aluminum housing uses a different seal and will not work. The second difference is that the D-21's used a 12mm ring gear bolt. Not a big deal if your not swapping carriers.

 

If your cruising the junkyards its easy to tell what rear end asnd ratio is in a truck. On the #'s plate you will see an axle code. I believe HL is the code for the H-190. They also came with the c-200 and H-233b. Whatever # follows the HL will tell you the gear ratio. 3.7, 3.8, 4.1, 4.3. Hope this helps

[pope_face]

Awesome, thanks a lot... I'd rather avoid having to change out the axles to the wagon ones, so I'll likely just try to stick with the truck ones.

 

As for the actual ratios themselves, I've got the 4.88 ATM from the J13 that's in the truck... it's a nice gear ratio to have, but assuming a 1:1 4th gear ratio for an L-Series auto and stock tire diameter I'll have to be running at about 4000-4500 rpm just to keep up on the highway... I know the engines were designed for 6500-7000, but I'd rather not have to run that hard if I don't have to. I'll see if I can track down a 3.8 or a 4.1... that'll likely work best for me.

[pl521sss]

Awesome, thanks a lot... I'd rather avoid having to change out the axles to the wagon ones, so I'll likely just try to stick with the truck ones.

 

As for the actual ratios themselves, I've got the 4.88 ATM from the J13 that's in the truck... it's a nice gear ratio to have, but assuming a 1:1 4th gear ratio for an L-Series auto and stock tire diameter I'll have to be running at about 4000-4500 rpm just to keep up on the highway... I know the engines were designed for 6500-7000, but I'd rather not have to run that hard if I don't have to. I'll see if I can track down a 3.8 or a 4.1... that'll likely work best for me.

 

Nothing wrong with L16 @ 4500 or even higher.

Just expect your ears ringing after the trip.

Specially with aftermarket exhaust.

And this is with the 4.37 gears on 521 not the 4.88

[pope_face]

I know the engines will handle the rpms, I'm just concerned about the fuel economy on the highway if I'm rolling for an hour or more at 4500 rpm... I don't drive on the highway that often, but if I do I drive far enough to want to keep my revs a little lower...

[datzenmike]

Awesome, thanks a lot... I'd rather avoid having to change out the axles to the wagon ones, so I'll likely just try to stick with the truck ones.

.

 

You couldn't use the wagon axles anyway. Besides being a different length, they are four bolt.

[dat521gatherer]

where now is this # plate that says the ratio?:confused:

[datzenmike]

where now is this # plate that says the ratio?:confused:

 

I don't think the 620 had this, but the 720s did, as did most Nissan vehicles starting in the early '80s? The 720 plate with this info is on the pass inside fender, under, but tight against the hood hinge and to the left of the wiper motor as viewed from the front. It would look something like this. This is NOT from a 720 but it would be similar.

 

NISSAN MOTOR CO. JAPAN

type........................WHD910

chassis

no.......JN1HUO5S6EX048458

model.........................015 P

engine...............L24(E) 2393

trans,axle.........L4N71B HE37

 

Axle info is to the bottom right and is an HE 3.7 ratio.

[albyneau]

It has been my experience that any H-190 3rd member will fit into any housing wether it be a wagon or a truck. The difference being in two places. Input flange and axle spline count. Trucks have 29 spline axles and wagons have 27. Check out this link for the gear ratios and how to distinguish.

 

http://www.nwde.org/...TID=3243&KW=lsd

 

 

 

Dead link~ got another one?

Also~ my ID plate ('71 521) shows no axle code

[albyneau]

 

Nothing wrong with L16 @ 4500 or even higher.

Just expect your ears ringing after the trip.

Specially with aftermarket exhaust.

And this is with the 4.37 gears on 521 not the 4.88

 

 

I've gotten conflictng reports of 521's having either 4.37's or 4.6?'s stock~ any insight?