naz Posted July 23, 2007 Report Share Posted July 23, 2007 Well my 521 rear end decided to blowup, lovely grinding coming from it now. It must somewhat be in pieces since it wants to physically lock the rear wheels. I think this is a good time to swap to something with a more reasonable gear ratio into my truck. I've heard the whole 620 rear end will just drop right in? What years are best and is the difference between the automatic transmission rear ends and the manual transmissions? Any helpful and educational advice would be appreciated :-) -Naz Quote Link to comment
datsunaholic Posted July 23, 2007 Report Share Posted July 23, 2007 What year 521? It matters. 521 rears (the whole axle) are pretty much unique width wise- 620 ones are wider. So it's best to swap 3rd members. Problem is, 620s have the same rear ratio for most years as most years of 521s. 521s that came with J13 engines have 4.88 ('68-69). L16 521s had 4.375 ('70-72). Most 620s had 4.375s as well- all except '72-73 HD (4.88), '73-74 Automatics (4.625) and '79 Manual Transmission (4.11). So EVERYTHING from '75-78 was a 4.375, as were '74 M/T and '79 A/T (and some 1/2T '73s). 3.889 ratios were found in 2WD, manual transmission '81-86 720s. Quote Link to comment
naz Posted July 23, 2007 Author Report Share Posted July 23, 2007 mine is a 72, thanks for the info! -Naz Quote Link to comment
Fineline Posted July 23, 2007 Report Share Posted July 23, 2007 If you look in the passenger fender of the 720's it will tell you the axle and ratio. It has a section on it that says axle or something. Look for an HL prefix. The other axle was a c-200 I believe. Easy to distinguish between the two. The gear ratio will follow the HL. Hope this helps. Quote Link to comment
datzenmike Posted July 23, 2007 Report Share Posted July 23, 2007 '83 on had C-200 with the Z24 , later models went up in size again. Quote Link to comment
datsunaholic Posted July 23, 2007 Report Share Posted July 23, 2007 Not all. My '83 has a H190. I've seen plenty of '85 and '86 with H190. The 4X4s all had C200s 83-on though. Quote Link to comment
Fineline Posted July 23, 2007 Report Share Posted July 23, 2007 I think they went with the h-233b with the v-6. I pulled and h-190 3rd member out of a 1990's HB. I dont know the exact year but i'm sure they used them well into the 1990's? Quote Link to comment
naz Posted July 25, 2007 Author Report Share Posted July 25, 2007 Well now it's time to go start hitting up yards, it will be nice to be able to drive my truck around again. -Naz Quote Link to comment
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