Goemon Posted November 4, 2021 Report Share Posted November 4, 2021 This first one is in my non molested 79 620 KC 4 speed 8Y2 and has a line on top in the casting This second one came from a 78-79 longbed frame that I am converting to a KC frame to replace my rotten one. It has a different number. 823 and has no line on top. is one for 4 & one for 5 speed? Or no difference at all? Thanks Quote Link to comment
datzenmike Posted November 4, 2021 Report Share Posted November 4, 2021 They were all H-190 differentials with 29 spline axles and side gears, so they will swap. All '75-'78 620 standards and automatics were 4.375 ratio. The '79 was 4.11 ratio but the 4.375 was an option. There's no way to tell from the outside casting numbers and lettering what ratios are inside. You can lift one wheel and spin twice while the other wheel is stopped and count the driveshaft turns to get the gear ratio well enough, but if taking the 3rd member out anyway the ratio is stamped on the outside edge of the ring gear. 37/9 ..... 4.11 and used only on the '79 620 that were fitted with the wide ratio 4 speeds to overcome this lower ratio 35/8...... 4.375 not sure, '79 mid ratio 5 speeds and automatics used this gear. The faint numbers are likely 38310-P0100 indicating an October '73 ('74 model year) and up differential case casting. The early ones probably would have been aluminum just like the earlier 521 and these are steel. Quote Link to comment
Goemon Posted November 5, 2021 Author Report Share Posted November 5, 2021 Damn, I just put it back in before I made the pics.... This is the first differential I have messed with. Are there advantages of one over the other if I use my 79 4 speed transmission? Thanks for the info Quote Link to comment
datzenmike Posted November 5, 2021 Report Share Posted November 5, 2021 The 4.11 would theoretically give better mileage. Lift one wheel off the ground, put transmission in neutral, turn raised wheel 2 times, count drive shaft turns. If you do have the 4.11 it was normal for it to have a wide ratio transmission with a higher 3.592 first gear. If a 4.375 it would have a 3.321 first gear. Quote Link to comment
Goemon Posted November 5, 2021 Author Report Share Posted November 5, 2021 I have it out and have not put the axles back in yet so that should be easy right now w/ one axle. The insides were purdy. I sandblasted the back plates after removal and blasted the 3rd member before I took it apart. I used the KC back plates because some dumbass didn't know what the two threaded holes were for on the drum so they tried to pry them off thus bending the shit out of the back plates. Mine only had a few extremely minor bent places around the perimeter that took only a few minutes to fix. Thanks, I will post my findings later. Quote Link to comment
datzenmike Posted November 5, 2021 Report Share Posted November 5, 2021 There are thin brass shims between the axle housing and the backing plate, don't loose them. They set the axle end play, the in and out movement into the differential. Quote Link to comment
Goemon Posted November 11, 2021 Author Report Share Posted November 11, 2021 My computer crashed when I tried to reply, just now found the time to pull the damn thang and read it. I found these numbers on the big gear E358 HL 831 The numbers start about where it looks like a 2. Now King Rat, WTF does 79 + 2 mean? and wtf chunk have I got here? Joe Quote Link to comment
datzenmike Posted November 11, 2021 Report Share Posted November 11, 2021 On 11/4/2021 at 1:19 PM, datzenmike said: if taking the 3rd member out anyway the ratio is stamped on the outside edge of the ring gear. 37/9 ..... 4.11 and used only on the '79 620 that were fitted with the wide ratio 4 speeds to overcome this lower ratio 35/8...... 4.375 not sure, '79 mid ratio 5 speeds and automatics used this gear. 37:9 or 37/9 = 4.1111 Quote Link to comment
Goemon Posted November 11, 2021 Author Report Share Posted November 11, 2021 So will this be Kosher with the 79 4 speed? Or do I need to use the member from the 4 speed? I have no idea... Quote Link to comment
Goemon Posted November 11, 2021 Author Report Share Posted November 11, 2021 I didn't plan on doing any of this until I found this on the 79 KC Quote Link to comment
Goemon Posted November 11, 2021 Author Report Share Posted November 11, 2021 This member came from a longbed frame. It may have had a 5 speed 1 Quote Link to comment
datzenmike Posted November 11, 2021 Report Share Posted November 11, 2021 4 minutes ago, Goemon said: So will this be Kosher with the 79 4 speed? Or do I need to use the member from the 4 speed? I have no idea... I don't know what you have. What's on the ring gear? Either 4.111 or 4.375 will work. There's no really bad choice. The 4.11 will give very slightly better mileage if used primarily for commuting. The 4.375 would be better if a work truck carrying loads. Quote Link to comment
Goemon Posted November 12, 2021 Author Report Share Posted November 12, 2021 I didn't want to remove the paint marks before the pics It is hard to to read. I'll see what I can do but it looked like E358 Hl 831 AFTER COFFEE !!!!! Quote Link to comment
Goemon Posted November 12, 2021 Author Report Share Posted November 12, 2021 OK, Got it clean, used some fine grit paper & a block to sand the top color off and it has............ E 35:8 HL 831.............. on the ring gear. What is it ( ? ) and will it work good w/ my 79 4 speed. Will I get more or less top end ? IDK I just know the one in the KC has about 500,000 miles on it, she was my daily for decades. We also did that picking thang back in the 80's with gas pumps. I put 100,000 on her the first year. Purchased in 87, the pic is 1988 Thanks Quote Link to comment
Crashtd420 Posted November 12, 2021 Report Share Posted November 12, 2021 35/8 looks like 4.375 gears... It's fine with a 4spd around town.... But if you are cruising at 70 on the highway your rpms would be high, around 3600- 4000..... 5spd will make highway driving better and get the rpms around 3000... In my 521 I have the L16 with a 5spd so I like the the 4.375 gears.... If you have the L20b the you could get away with 4.11 with a 4spd.... Quote Link to comment
datzenmike Posted November 12, 2021 Report Share Posted November 12, 2021 Stock tires, 4th gear and 4.375 @ 70...... 3,853 RPMs There are many different over drive ratios on different available 5 speeds but is assuming a truck mid ratio 5 speed or 0.864 (13.6% OD)...... 3,329 RPM Stock tires, 4th gear and 4.111 @ 70..... 3,621 RPMs (4.11 gear trucks only came with 4 speeds) IF you put a mid ratio 5 speed in (0.864 or 13.6% OD)..... 3,128 RPMs 1 Quote Link to comment
Goemon Posted November 13, 2021 Author Report Share Posted November 13, 2021 Many thanks to all of you. I believe I will pull the one in the KC and see what the ring gear has on it....time for more damn cleaning Quote Link to comment
Goemon Posted November 21, 2021 Author Report Share Posted November 21, 2021 I pulled the KC 3rd that has the cast line on top and the ring gear is 37:9. 4.11 correct? Quote Link to comment
Goemon Posted November 21, 2021 Author Report Share Posted November 21, 2021 A 1979 KC Quote Link to comment
datzenmike Posted November 21, 2021 Report Share Posted November 21, 2021 The '79 was the only year 620 that had a 4.11 ratio. I think only came with a 4 speed. Optionally, you could get a 4.375 Quote Link to comment
Goemon Posted November 21, 2021 Author Report Share Posted November 21, 2021 You mentioned the gearing on a 79 620 transmission was different. Or did I dream that??? I could not find the gears when we went to rebuild it. Nissan had another gear package but no instructions. That is what I came up with so I had to put all the old gears back in Or did I dream that also? Quote Link to comment
datzenmike Posted November 22, 2021 Report Share Posted November 22, 2021 The 4 speed that was used with the 4.11 was a wide ratio with a 3.592 first gear. Quote Link to comment
Goemon Posted November 22, 2021 Author Report Share Posted November 22, 2021 Is First gear is the only different gear? Thanks Quote Link to comment
Goemon Posted November 22, 2021 Author Report Share Posted November 22, 2021 Is the transmission on this list? Quote Link to comment
datzenmike Posted November 22, 2021 Report Share Posted November 22, 2021 4 speeds... The F4W63L* marked as an option isn't right. The 510 wagons all had this transmission and the same one as used in the L16 powered PL521 5 speeds... The dogleg shift pattern FS5W60L was only used in the '79 210 and not the later 510 (A10 HL510) The FS5W60A H pattern was used on the '80- '82 210s The 26" long dogleg shift pattern FS5W63A was used in the S10 (not S110) 200sx and was an option in the A10 (later HL510) and the '77 and up B-210. It was not an option in the North American 610 but was used in Japan and Australia in the long 31.5" length. The FS5W71B was used in the 620, 720 trucks, 280z, 280zx 810 and Maxima, the S110 200sx, S12 200sx not after '86.5 and in various ratios. The FS5W71C was never used in the 620 truck, but was used in the '84-'86 n/a 300zx, D21 Hardbody, S13 and S14 240sx. (The F4W71C 4 speed was used in the Vanette and the '88-'92 D21 Hardbody) The FS5R90A was also used in the 'Jan '82 and '83 280zx The 71B 4 speed was first used in the '74 620 F4W71B 4 speed (wide ratio) used on all '74-'79 as the standard transmission. 1st..... 3.592 2nd... 2.246 3rd... 1.4156 4th... 1.000 FS5W71B optional 5 speed (mid ratio) used on '77-'79 model years. 1st..... 3. 321 2nd... 2. 077 3rd... 1.308 4th... 1.000 5th... 0.864 All years '74-'78 were 4.375 differential except the '79 which was 4.11 '79 used a wide ratio 4 speed with the 4.11 differential '79 optional 5 speeds used a 4.375 differential. 1 Quote Link to comment
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