LSD options for h190

[Wildcat Walker]

                                                                                                                   Update on Narrowing an H233 to suit a 720:

 

Axle Widths:

620 H190 Axle Flange to Axle Flange A_FF1 = 52.15625 in

720 H190 Axle Flange to Axle Flange A_FF2 = 55.875 in 

WD21 ( 29 spline, Rear Drum) H233 Axle Flange to Axle Flange A_FF3 = 58.1875 in 

Xterra (31 spline, Rear Drum) H233 Axle Flange to Axle Flange A_FF4 = 61.875 in 

 

Note that the axle widths (A_FFX) you measure in the field may vary depending upon how your axle bearing preloads (H190 and WD21 rear drum) are set (shimmed). You should always measure YOUR unit and calculate the amount to be narrowed from YOUR unit. The WD21 (Rear Disc) & Xterra H233s utilize a dual tapered roller bearing assembly on the axles and the preload is not set by shims, therefore the measurement axle flange to axle flange you measure will vary based on manufacturing differences. If you can find a rear disc WD21 or Xterra H233, use those units instead of the WD21 rear drum, the advantages of these are obvious. 

 

The WD21 (rear drum) H233 axles can not be narrowed to suit a 720.  ((A_FF3 - A_FF2)/2) = 1.15625 in  <- This is the amount to be cut from each axle. Because the original splines are cold rolled into the axle shaft, the machined diameter of the shaft at the axle end is slightly smaller than the major diameter of the finished splines. In order to narrow the axle and cut new splines, the axle must have a diameter greater than or equal to the diameter of the finished splines.  What this means is, that we are not cutting enough off of the axle to get down to the "meat".  In the image below of the WD21 Axle, one would need to cut about 3 inches minimum to have enough material to cut new splines. 

 

The same is true for using an Xterra H233. ((A_FF4 - A_FF2)/2) = 3.00 in  One would need to cut about 4.25 inches off. When I narrowed the Xterra unit for my 620 I cut 4.9 inches off of these, more than enough. 

 

The only solution I see for narrowing an H233 to suit a 720 (stock width) is to narrow and re-spline the 31 spline Xterra axles to 29 spline (WD21) and use the 29 spline LSD side gears. If you play around with the math you will see that the 620 H190 is about 3.72 inches narrower than the 720 H190 and either the WD21 or Xterra H233 can be narrowed to suit a 620. This solution is based on the assumption that the heat treatment is deep enough in the 31 spline axle to machine down to a 29. These axles are known for being very hard and the WD21 and Xterra un-splined axle diameters are very close in size. Only one way to find out, back to the junkyard! 

 

31 spline Xterra on left, 29 WD21 on right. The splines are identical. The respective side gears in the LSD units will interchange. 

 

 

 

 

Edited March 17 by Wildcat Walker

[]2eDeYe]

Excellent tech. Keep up the great work 🙂

[Icehouse]

Awesome info!  Keep it coming!!   All rigs must have a LSD!  

 

I saw one post early on in the thread that showed the 3rd members next to each other.  Are the driveshaft flanges bigger on the H233 vs. H190 my guess is yes but I haven't verified it.  Have you guys?  I want to swap in a H233 into my 2WD D21, I have 2 LSDs in my shed for the H233.  The 2WD D21 drifts like garbage with the open diff.  If anyone local the Everett has a H233 stashed away they want to part with let me know.  Pick and Pull wants over 200 for the axle...  Gotta wait till half off day haha. 

[Wildcat Walker]

17 hours ago, Icehouse said:

Awesome info!  Keep it coming!!   All rigs must have a LSD!  

 

I saw one post early on in the thread that showed the 3rd members next to each other.  Are the driveshaft flanges bigger on the H233 vs. H190 my guess is yes but I haven't verified it.  Have you guys?  I want to swap in a H233 into my 2WD D21, I have 2 LSDs in my shed for the H233.  The 2WD D21 drifts like garbage with the open diff.  If anyone local the Everett has a H233 stashed away they want to part with let me know.  Pick and Pull wants over 200 for the axle...  Gotta wait till half off day haha. 

The driveshaft flange flange/yoke on the H233 is much larger than the H190. The WD21 with H233 uses a Spicer 1310 U-joint. I'm not concerned with trying to match any junkyard parts for the driveshaft, as I will be running a custom shaft. There may be a bastard joint out there that you could adapt a 620 shaft to a H233 yoke, just know that you may be shifting the "fusible link" in the driveline to the driveshaft. 

 

As for swapping an H233 into a D21 you wont need to narrow or do any modifications. I pulled a 3.7:1 gearset out of a D21 w/H233 last weekend. If you already have the LSD 3rd member you can drop it right into a non LSD housing with axles. Look for a D21 that's king cab, 2wd, and VG30, it will be a bolt in affair.  

[Wildcat Walker]

If anyone with a 520, 521, or 620 is interested in a H233 swap (minus driveshaft), please reach out. I have enough extras to build ONE narrowed unit and offer it for sale. If interested please PM. We can discuss gearing, brakes, etc. I'll be sending axles out to Dutchman in about 2 weeks. 

[Crashtd420]

57 minutes ago, Wildcat Walker said:

If anyone with a 520, 521, or 620 is interested in a H233 swap (minus driveshaft), please reach out. I have enough extras to build ONE narrowed unit and offer it for sale. If interested please PM. We can discuss gearing, brakes, etc. I'll be sending axles out to Dutchman in about 2 weeks. 

I should have looked deeper into this before I did coilovers and 5linked my 521..  

Still have to hope and find a lsd for the h190....

[Pounding Rox Truck Shop]

1 hour ago, Wildcat Walker said:

As for swapping an H233 into a D21 you wont need to narrow or do any modifications. I pulled a 3.7:1 gearset out of a D21 w/H233 last weekend. If you already have the LSD 3rd member you can drop it right into a non LSD housing with axles. Look for a D21 that's king cab, 2wd, and VG30, it will be a bolt in affair.  

 

Not questioning your expertise but just curious if you can give more details on this D21 King Cab 2wd V6 axle you found. Was the door tag an actual HG37? I don't think I have ever encountered one of those. I have a H233b out of a long bed 2wd V6 with LSD and it's a HG43 or 4.375 ratio. The only 3.70 ratio I know of came out of the 2wd auto 4cyl trucks but they were all HF37 axle codes, H190 as you would already know. Can you verify you found a HG37 and give us more details on the truck itself?

 

Up ill now this has been the bible shared across most platforms, if it needs to be updated I will pass this info along.

https://www.infamousnissan.com/forum/archive/index.php/t-976.html 

[Tank.]

41 minutes ago, Crashtd420 said:

I should have looked deeper into this before I did coilovers and 5linked my 521..  

Still have to hope and find a lsd for the h190....

Me too...I searched really hard several years ago but it seems to be a unicorn.

[Wildcat Walker]

48 minutes ago, Pounding Rox Truck Shop said:

 

Not questioning your expertise but just curious if you can give more details on this D21 King Cab 2wd V6 axle you found. Was the door tag an actual HG37? I don't think I have ever encountered one of those. I have a H233b out of a long bed 2wd V6 with LSD and it's a HG43 or 4.375 ratio. The only 3.70 ratio I know of came out of the 2wd auto 4cyl trucks but they were all HF37 axle codes, H190 as you would already know. Can you verify you found a HG37 and give us more details on the truck itself?

 

Up ill now this has been the bible shared across most platforms, if it needs to be updated I will pass this info along.

https://www.infamousnissan.com/forum/archive/index.php/t-976.html 

I would be glad to share. I take pictures of all the door tags (if present) for future reference. 

 

 

The H233 has several gear options available. The Nissan Catalog will only show gear sets on the specific model that you have open in the catalog. 

 

Genuine OEM Nissan Parts and Accessories Online - Nissan Parts Deal

 

This VIN yields ONLY a 3.7:1,  Part Number 38100-01J10. The crown wheel is marked 37:10 or 37 divided by 10 = 3.7.  The 3.7 set is discontinued, so available NOS or used only. 

 

NOTE: The 3.7:1 is found in D21, VG30, 2wd, king cab, MANUAL trans, The 3.9:1 is found in D21, VG30, 2wd, king cab AUTOMATIC Trans.

 

In my 620 I will be running the 38100-02J71, 3.9:1

 

There's also a 4.10, 4.11, 4.375, 4.625, 4.63, 4.875, 4.88, 5.13, 5.143, 5.57, 5.571, 5.857, 5.89. 

 

 

 

Edited March 18 by Wildcat Walker

[Pounding Rox Truck Shop]

Neat! Stupid question but are you in the USA? I ask because that late of a build date would technically make it a 96 and the VG30 was not available stateside starting in 96. 

Edited March 18 by Pounding Rox Truck Shop

[Wildcat Walker]

14 minutes ago, Pounding Rox Truck Shop said:

Neat! Stupid question but are you in the USA? I ask because that late of a build date would technically make it a 96 and the VG30 was not available stateside starting in 96. 

I live in Middle Earth, the Shire to be exact.  

 

Yes, I live in KY. 

 

Also, the link you shared there is mention of the H233 3rd member-to-housing switching from 9 to 11 bolts somewhere around 1990. It is true that the snout of the 3rd members are interchangeable between housings, but the ring gears (crown wheel) will NOT interchange between 3rd members. This is due to the 10mm vs 12 mm ring gear bolts, the 12mm being post 1990. This isn't really a big issue as the vast majority of H233s encountered in the yard will be post 1990. 

Edited March 18 by Wildcat Walker

[Pounding Rox Truck Shop]

That is pretty interesting, even the FSMs fail to list that as an available ratio setup. I will have to key my eye open because 3.70 is way more streetable in a 4cyl than 4.375 with tall tires will ever be.

 

My 2wd h233b HG43 code is from 1986.5.

Edited March 18 by Pounding Rox Truck Shop

[iceman510]

10 hours ago, Wildcat Walker said:

I live in Middle Earth, the Shire to be exact.  

 

Well not very exact.  I mean, is it the South Farthing, West Farthing?  Bywater, Hobbiton?  Inquiring minds want to know.  😁

[wayno]

I myself am not a big fan of the LSD, my backend started coming around on me too many times, the last time I was in traffic and had to let off and scare those in back of me when normal people are picking up speed(tilted surface traveling uphill), I removed it when I found 3.3 gears for my 521 kingcab SD25 diesel(turbocharged), they are more freeway friendly for my diesel engine.

 

Does the H233 come with something close to 3.0 gearing?

 

I need better gearing, I have the torque to turn 3.0 gears, but I do not think I can turn 2.7 gears when starting out say when starting up hill, I can get it moving in 2nd gear, but I am riding the clutch more than I like.

[datzenmike]

Yes, LSD's Achilles heel is turning or curve, and tilted or crowned road. Great for straight ahead.

[Wildcat Walker]

12 hours ago, wayno said:

I myself am not a big fan of the LSD, my backend started coming around on me too many times, the last time I was in traffic and had to let off and scare those in back of me when normal people are picking up speed(tilted surface traveling uphill), I removed it when I found 3.3 gears for my 521 kingcab SD25 diesel(turbocharged), they are more freeway friendly for my diesel engine.

 

Does the H233 come with something close to 3.0 gearing?

 

I need better gearing, I have the torque to turn 3.0 gears, but I do not think I can turn 2.7 gears when starting out say when starting up hill, I can get it moving in 2nd gear, but I am riding the clutch more than I like.

 The tallest ratio available is the 3.7. You do not want a 3.0, there is a point at which you will have trouble maintaining a highway speed limit, especially on grades. I drive a 1990 Chevy 1500 with 4.3 and 3.08 gears. It loves to do 90 mph on the highway but there is no gear in which one can comfortably cruise about 60 mph. In 4th gear the sweet spot is 45-50 and 5th gear 70-75mph. On the highway, on any grade, load or not, it's a constant battle between 3rd and 4th just to TRY and maintain speed. 

10 hours ago, datzenmike said:

Yes, LSD's Achilles heel is turning or curve, and tilted or crowned road. Great for straight ahead.

And spider gears (pinion gears as Nissan calls them) are the Achilles heel of an engine swapped 620. The sudden transfer of torque from one axle to another as traction between the back wheels varies absolutely hammers the spiders. With the LSD, this internal motion is minimized while still allowing some slippage for turns. Yes in wet or slippery conditions that the back end may have tendency to get loose, especially with skinny tires, but this has a lot to do with the short wheel base. When I was running the H190, the back end would easily come around, so the lack of an LSD did not provide immunity from this phenomenon. The benefit of greater strength and traction is worth the small decrease in wet stability. The new Z, as well as many high end Japanese sports cars come with a clutch type LSD.  I drove the new Z in a sport trim without LSD, and it was rowdy making a turn with slight throttle, the lack of traction caused the instability. LSD for street, locker for off road, open diff for daily driver. 

Edited March 19 by Wildcat Walker

[Pounding Rox Truck Shop]

If you want highway gears for the H190 most of the D21 regular cab 2wd manuals came with HF35 axles which have 3.54 gears. If you want pep the 2wd King Cab D21 auto  trucks from 96-97 had HF41 axles which are 4.11 gears. Or split the difference by using a 2wd regular cab auto from the early 90s which had HF37 axles, 3.70 gears. These are all H190 axles btw. I have a HF41 axle in my stash that I want to drop in my 95 D21 regular cab just to see how much fun it it would be. I used a HG43 in a regular cab 2wd maunal truck and it would take off the line insanely but topped out at 60mph, even with tall rear tires it was not highway speed friendly. I built the truck for small course autocross tracks but never got to run it on a short track, SCCA switched locations and it was all "corvette tracks" which speeds over 70mph and with my R compound tires I was hitting 3rd gear just to bang off the rev limiter the entire track. 3.70 HG37 gears would have solved my problem.

 

*Next to none of the D21 H190 diffs had LSD.

Edited March 19 by Pounding Rox Truck Shop

[wayno]

11 hours ago, Wildcat Walker said:

 The tallest ratio available is the 3.7. You do not want a 3.0, there is a point at which you will have trouble maintaining a highway speed limit, especially on grades. I drive a 1990 Chevy 1500 with 4.3 and 3.08 gears. It loves to do 90 mph on the highway but there is no gear in which one can comfortably cruise about 60 mph. In 4th gear the sweet spot is 45-50 and 5th gear 70-75mph. On the highway, on any grade, load or not, it's a constant battle between 3rd and 4th just to TRY and maintain speed. 

And spider gears (pinion gears as Nissan calls them) are the Achilles heel of an engine swapped 620. The sudden transfer of torque from one axle to another as traction between the back wheels varies absolutely hammers the spiders. With the LSD, this internal motion is minimized while still allowing some slippage for turns. Yes in wet or slippery conditions that the back end may have tendency to get loose, especially with skinny tires, but this has a lot to do with the short wheel base. When I was running the H190, the back end would easily come around, so the lack of an LSD did not provide immunity from this phenomenon. The benefit of greater strength and traction is worth the small decrease in wet stability. The new Z, as well as many high end Japanese sports cars come with a clutch type LSD.  I drove the new Z in a sport trim without LSD, and it was rowdy making a turn with slight throttle, the lack of traction caused the instability. LSD for street, locker for off road, open diff for daily driver. 

 

I had an H190 LSD with 3.54 gears in my 521 kingcab SD25 turbodiesel, when it was wet out it was hard to drive under certain circumstances, like entering from the right a left curved uphill tilted to the left freeway entrance like I described in my last post, the backend came close to hitting the cement wall, I had to let off and cause issues with all the traffic behind me, after that time I started hunting for the rare 3.3 gears Nissan put in the mileage option 720 trucks with the Z20 engine, them gears are way nicer than the 3.54 gears in the LSD, I am always hitting the clutch on the freeway looking for the phantom 6th gear I do not have thinking I am till in 4th gear.

 

I have an SD25 diesel engine, redline is 4000rpms, since figuring out how to turbocharge this vacuum controlled throttle diesel engine I have wanted a 6th gear, 70mph is 2500rpms, if I step on the pedal a 100mph is not that far away, but 100mph is 4000rpms which is redline for this engine, I do want 3.0 gears as I have plenty of torque to get it moving from a standstill, and I am positive I will be able to do 70+ at 2000rpms.

 

I adjusted my boost to not exceed 7psi a few years ago as it had almost the same pull as when at 20psi, I am fairly sure I would wear out or destroy the engine putting 15psi to 20psi all the time, the engine was rated at 71hp stock, I can walk away from a stock 720 gas powered engine on the freeway and they are rated at somewhere around 120hp, I said walk away, I do not think I could run away from one, anything above 70mph I will pull away until 100mph at which point I let off the pedal as that is redline.

 

You have been talking about widening the axle, my 1986 720 axle I have now is 3 to 4 inches inside the fenders I have on my step side box on the truck, this is why I was thinking that the H233 axle might bring the tires closer to the inside of the fender, this is why I asked about the H233 gearing, I need something close to 3.0 gears.

 

Its the red one I am talking about.

 

Edited March 20 by wayno

[Wildcat Walker]

wayno, your situation is unique. The torque vs rpm curve for your diesel engine is a bit different than the comparable gasoline engine.  Whatever gearset suits your roadways, driving style, and rig is 100% subjective. As for your axle width, sounds like you could swap a WD21 sourced H233 without any narrowing at all. I have no idea the dimensions of that aftermarket step-side bed. As for widening an axle, I don't see any way to do it with any sort of longevity, other than having custom axles made, which would be cost prohibitive. Neat rigs for sure! I've always wanted an SD in a 510. 

[wayno]

Well I need to find something with 3.0 gearing that will except 14" 6 lug 620 disc brake rims.

 

The SD series diesel engines are heavy, I expect the 510 front suspensions would be at the limit or over it.

Edited March 21 by wayno

[datzenmike]

wayno what 5 speed  do you have?

 

If 70 MPH, 3.3 differential and 26" tires forth is 2,985. If you have a mid ratio with 0.864 5th gear then 2,579 RPMs 

 

At 100 MPH that's 3,684 RPMs well below 4,000.

[wayno]

18 hours ago, datzenmike said:

wayno what 5 speed  do you have?

 

If 70 MPH, 3.3 differential and 26" tires forth is 2,985. If you have a mid ratio with 0.864 5th gear then 2,579 RPMs 

 

At 100 MPH that's 3,684 RPMs well below 4,000.

 

I have no idea what transmission is in there other than it is a "Short Shaft", it is the only one I have in a vehicle now with a short shaft, I could likely convert over to a long shaft but it has a custom length driveline I had made, I prefer long shafts because I do not have to lean forward to shift into 5th gear like I do this truck, but that does not stop me from driving it, it is my favorite vehicle to drive.

 

At 70pmh I show right around 2500rpms, as I recall the last time I had it going 100mph it showed about 3900rpms but I might have been going a little more than a 100mph, this person was bugging me so I left him behind, in my rear-view mirror I seen him take the next exit.

 

I want better gears because of another reason also, 70mph is 2500rpms, but the engine likes 2300rpms, to get that extra 200rpm I have to step deeper on the pedal, I get 30mpg going 75mph, if I could keep in under 2300rpms I would likely get 35+mpg as I have done that doing 65mph(under 2300rpms), the guy that I bought the other SD25 engine I have in the 720 from drove 50/55mph on the freeway, and with propane injection(crude setup) he claims to have got 48mpg, I have that setup to this day, but I considered it a hassle and did not want to constantly be thinking about it, plus I cannot drive 55mph, I never did try to see what kind of mileage I could get going 75mph because at that time the EGTs on that engine ran way too hot to be driving it that way, this was before I figured it all out and it does not run hot like that anymore but it has a different turbocharger and is not the same as my 521 kingcab, but it will pull anything behind it, it has way more torque than my 521.

 

By the way, all my diesel trucks have 3.3 gears in them, so did the vehicle I bought that other SD25 turbocharged diesel engine from, I cannot remember the tire size that was on that Volvo Wagon the SD25 was in.

Edited March 21 by wayno

[bilzbobaggins]

On 3/18/2024 at 10:08 AM, Pounding Rox Truck Shop said:

Neat! Stupid question but are you in the USA? I ask because that late of a build date would technically make it a 96 and the VG30 was not available stateside starting in 96. 

Prolly a canadian model.

[datzenmike]

The '86 model year would begin June '85, the last 720 was off the line 11 '85, that's November. Car number 351,280

 

The first D21 off the line was December '85 offering VG30i and Z24i engines

[Wildcat Walker]

On 3/20/2024 at 8:32 PM, wayno said:

Well I need to find something with 3.0 gearing that will except 14" 6 lug 620 disc brake rims.

 

The SD series diesel engines are heavy, I expect the 510 front suspensions would be at the limit or over it.

I no longer have a 510 and with todays prices, probably never will. I'll be lucky to get my 620 and my 69 FJ40 built before I die.