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DREWSDIME

720 4x4 front diff R180?

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K definitely does not mean 4 pinion. Did they maybe start stamping them when they went with the different crown gear inner diameter and bolts in ~76/77?

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I think it was closer to 80 but don't know for sure. That would have had to be on the Z car. 720 4x4s started in '80....

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P4080007_zpsaa5b039d.jpg

 

The S6000 housing was on ALL 720 4x4s so they must all be Ks.

 

The 280z is a totally different number to '78

 

The '79 and up 280zx non turbo and Maxima use an S5000 and an S7000 so they may be Ks.

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I'm saying the case number on all 720 4x4s and later S12 were all the same and marked with a K. Others may have had a K on them but all Z car housing numbers were the same, no change.

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"Pretty sure it was after 8/76 when they went to 115mm ring"

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A post on Ozdat.....

..."ONly the K stamped diffs have a 115mm crownwheel unless the guts have been swapped over into a old casing...

 

http://ozdat.com/forum/viewtopic.php?f=29&t=11451&start=45

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Well, that would make sence since all 115mm diffs were made after 76, but I think mike is saying non-K diffs were still being used after 76.

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Thanks Matt. Yes all ZX non turbo cars had the same part number so the same housing (may be a K or maybe not) but no changes. The number S5000 and S7000 is suspiciously similar to the 720's S6000. That's all. 

 

 

What part is the 115mm ring. If the crown gear is 180mm.

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I misspoke and meant to say "all 115mm diffs were made after 76".  The inside diameter of the crown gear went from 110mm to 115mm after 8/76.  I think they also changed to a larger bolt size.  I believe I've seen people use sleeves on the bolts to use the later 115mm crown gear on an older carrier.

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I need to pull apart an earlier 438 and confirm pinion count.

Also need to check out that 85/4.11.....casing/PN must be different (?) due to the fact that it's the only I have with clip in stubs.

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Maybe the 720 with auto hubs only had the clipped in stubs???

Edited by Sealik

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I am actually looking for a front diff for my 06/1983 . I had some rear differential trouble and ended up putting a aluminum housing 4.375 rear diff from a 71 Datsun 521on my 720 4x4 I really like the get up and go it has but would also like to be able to utilize the 4x4 but the front diff is the stock HF38 I was to understanding most these had 4:11s this one didn’t I seen it mentioned that the 80-early 83 had 4.375 but I also recalled that in 83 they made the shafts uneven lengths how would I go about getting a 4.375 front diff but being able to plug and play it 

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I think I mentioned earlier that there were some early months in the '83 model year where a 3.9 ratio was used and then around Christmas was switched to 4.11. My info isn't clear on this maybe both were used through the '83 model year. Is yours a regular cab???

 

For a 4.375 R180 you would need one from an '81-'82 720 4x4. NOT an '80 they were offset to the opposite side at the front than all the later 720 s with Z series engines. Look on the engine tag, on the right (passenger) side inner fender just below the hood hinge. If it says HF37 (right bottom of tag) that's the one. 

 

My guess is you could probably remove the 1980 front differential and remove the parts that offset it to the left? and swap later 720 parts onto it. 

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1 hour ago, datzenmike said:

I think I mentioned earlier that there were some early months in the '83 model year where a 3.9 ratio was used and then around Christmas was switched to 4.11. My info isn't clear on this maybe both were used through the '83 model year. Is yours a regular cab???

 

For a 4.375 R180 you would need one from an '81-'82 720 4x4. NOT an '80 they were offset to the opposite side at the front than all the later 720 s with Z series engines. Look on the engine tag, on the right (passenger) side inner fender just below the hood hinge. If it says HF37 (right bottom of tag) that's the one. 

 

My guess is you could probably remove the 1980 front differential and remove the parts that offset it to the left? and swap later 720 parts onto it. 

Mine is a mid 83 king cab deluxe I do remember something being mentioned about the offset I just made the assumption it was something that occurred when the truck was assembled in America in Smyrna TN at the same time the C200 was put in the 4x4 version the offset was for the awkward Z oil pan wasn’t it . If I can get my hands on one of these front diffs with the correct gearing I will be in business or I will have to convert my front and rear end to a newer set up from the easier to find 84-85.5 I occasionally find in the scrap yards 

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bXXCoJM.jpg

 

This is the 1980 oil pan from the last year L20B. You can see that the pan is off set to the driver's side to make room for the differential on the passenger side. The R-180 had a small axle and extension to the driver's side and then the CV axle.

 

All other years used the Z series engines Z22 and Z24 in the 4X4 and it was opposite to this with the pan off set to the passenger side and differential on the driver's side.

 

Either R-180 you should be able to remove the stub axle and swap sides. Pretty sure.

 

In all cases the CV axles swapped all years but the 1980s were opposite in that the driver's side had to go on the passenger sides if put on an '81 and up.  Does that make sense. Also the front CVs are no longer available so if you find any, grab and save them.

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