1979 H190 3.88 make that 4.875 ring & pinion

[Danz]

I am trying to locate a H190 3.88 4.875 ring & pinion for a 1979 Datsun king cab pickup

 

[ggzilla]

the HE38 is 35 tooth ring gear with 9 tooth pinion gear 35/9 = 3.889:1 gear ratio

 

This is perhaps the most common H190 gearset, used on Roadster, 510 wagon, 610 wagon, S12 200SX, and 620 and 720 and D21 and D22 pickups

[80datson]

I might have one for you..

[Danz]

80datsun- I am interested. How can I find out more information? I am located on so cal. 

[Danz]

My original ask was incorrect it is a H190 4.88 ring and pinion, 29 spline. Nissan part number 38100-V7400

[datzenmike]

Can't find that part number. There were no 29 spline '79 H-190 38100 gear sets in 4.875. The '65-'68 520 and '69 L521 all had 4.875 equipped H-190 29 spline differentials. I believe the carrier was made of aluminum. Later trucks didn't go above 4.625 I believe.

 

The '79 620 only came in 4.11 and an optional 4.375. If wanting 4.875s find an old 520

[Danz]

I have a 520 H190 aluminum carrier with 4.88 ring and pinion but broke two teeth on the ring. I can’t find a replacement ring & pinion for that one either. Any ideas where I can look for that one? Any idea what the part number is. 

[ggzilla]

Nissan Competition sold a 4.875 ring & pinion set 38100-Y4006, code HD48 for aluminum carrier

 

This is a rare racing piece. Keep watching eBay and racing web sites, and when you see one for sale, buy it

[80datson]

4 hours ago, Danz said:

I have a 520 H190 aluminum carrier with 4.88 ring and pinion but broke two teeth on the ring. I can’t find a replacement ring & pinion for that one either. Any ideas where I can look for that one? Any idea what the part number is. 

I have a h190 in my back yard that has aluminum carrier and has 6 bolt axles not sure what it came off of? Maybe 520

[datzenmike]

Find an old J13 powered 520 or first year '69 L521. These all had the 39/8=4.875 (not 4.88) gears in an aluminum case or third member. Just swap the new one in. 

 

38100-14900 or 38100-20659 up to 09 '65

38100-14901 and 38100-20600 10 '65-06 '69

 

The more teeth you put on a 190mm diameter ring the smaller and weaker the teeth get.

[ggzilla]

1 hour ago, datzenmike said:

Just swap the new one in. 

you can either swap the ring & pinion set in, or swap the entire 3rd member in. The latter is easier and more foolproof, as the gears have already been installed, measured, and the correct shims chosen

[Danz]

This goes back to my original question. Where can I find/purchase a ring & pinion or the whole differential? None of the local junk yards have anything that old and I can find no business that carries the ring & pinion?

[datzenmike]

Now changed to a 3.88?

 

All years of 720 2wd had 3.889 available on some models, not the 4x4s though. If in wrecking yard look for the engine plate riveted to the passenger side inner fender below the hood hinge.

 

 

Very bottom right the gear ratio will be stamped there. 

 

HF is the H-190 and 38 is 3.889

[ggzilla]

1 hour ago, Danz said:

Where can I find/purchase a ring & pinion or the whole differential? None of the local junk yards have anything that old and I can find no business that carries the ring & pinion?

yea it's a challenge keeping our older classics up and running

 

* Ratsun classified wanted Classifieds - Ratsun Forums

* eBay, keep looking. And when you find it, buy it

* Use the nationwide auto wrecking hotline or https://www.car-part.com

* Amayama inquiry

 

Nissan GEAR SET, FINAL DRIVE 38100-P0501 3.889

[Danz]

This goes back to my original question. Where can I find/purchase a ring & pinion or the whole differential? None of the local junk yards have anything that old and I can find no business that carries the ring & pinion?

[datzenmike]

Now changed to a 3.88?

 

All years of 720 2wd had 3.889 available on some models, not the 4x4s though.

 

 

[ggzilla]

  

8 hours ago, Danz said:

Where can I find/purchase a ring & pinion or the whole differential? None of the local junk yards have anything that old and I can find no business that carries the ring & pinion?

yea it's a challenge keeping our older classics up and running

 

 

You can find those parts at these places:

* Ratsun classified wanted Classifieds - Ratsun Forums

* eBay, keep looking. And when you find it, buy it

* Use the nationwide auto wrecking hotline or https://www.car-part.com

* Amayama inquiry

 

Do you want the 3.889 (HE38) or the 4.875 (HE48)? Neither came from the factory in the 620 pickup, but you can put it in a 620

[Danz]

I want the 4.875. I get that they did not come from the factory for my truck but it is what I need because I converted the truck to a 4wd with a kit. 
How should I search on the “nationwide auto wrecking hot line”? It asks for the year, make, model but my truck did not come with 4.875? 

[datzenmike]

It did not. 4.625 was the highest in the '73 automatic. Look under H-190 this is the differential name. If it fits an H-190 it will fit your truck. BTW,  29 spline side gears can be changed into it.

[Danz]

Will the differential in a 1966 Datsun roadster fit in my 620 truck axle? Or can I at least remove the 4.875 ring & pinion from that differential? There is one for sale on eBay but it says it won’t work in my truck.https://ebay.us/m/L9h8LX

[datzenmike]

Roadster won't have a 4.875 in it.

 

Car H-190 have 23 spline side gears, trucks have 29 spline side gears What you can do is partially dis-assemble both and swap our truck side gears into the roadster unit. Roadster parts tend to be more expensive so don't pay almost $300 for it. Lots of 720 2wd trucks have the H-190 and 3.875 in them. 

 

https://ratsun.net/topic/10748-h190-spider-gear-swap/ 

[Danz]

I have had no luck finding a 4.875 ring and pinion or differential with that gear ratio in it. Do anyone know of a business that can make one? Or is there a axel from a Toyota or later Datsun/Nissan that can replace my current one that would have the 4.875 gears in it?

 

 

[datzenmike]

Having one made??? Prohibitively expensive. Try an off road after market company for Nissan parts. 

 

 

On 6/26/2025 at 8:37 AM, datzenmike said:

Find an old J13 powered 520 or  L521 (not PL521) These all had the 39/8=4.875 (not 4.88) gears in an aluminum case or third member. Just swap the new one in. 

 

38100-14900 or 38100-20659 up to 09 '65

38100-14901 and 38100-20600 10 '65-06 '69

 

The more teeth you put on a 190mm diameter ring the smaller and weaker the teeth get.

 

I think these were all aluminum case. 

 

 

Toyota:

 

 

 

F=7.5" (close to H190) or G 8" diameter + 14 (4.875) +2 (number of pinions)

F or G 14 2 is what to look for. This will not fit the H-190 axle housing so you will need the entire Toyota axle assembly and it will need to be close to the same width WMS to WMS (wheel mounting surface)

 

Keep looking for an old '65-'69 520 or L521 with J13 engine.

[wayno]

I made a few gear sets for Datsun 320 trucks for members who wanted better gears for their 320, I made one set with 3.5 gears for a NL320 with a LD20 diesel engine in it, he suggested it was great.

 

If you can find a 320 with 4.8 gears you can put your side gears into that gear set, it is not that hard to do, I have done it several times, it can be a pain getting the 320 pin out holding everything in place, just use your roll pin to put it back together.

Edited August 14, 2025 by wayno

[datzenmike]

wayno, is there an issue with bolt sizes? SAE ring gear holes being fitted to later metric housing. You would have to use the metric fasteners but do they fi the SAE holes? or do they need to be drilled out?

 

1/2" SAE bolt is 12.7mm but the metric bolt is likely 13mm