Axle issue emergency

[denveratsun]

30 miles east of Barstow....drove all the way from Denver perfectly....rear pinion is makin noise. Getting worse. High pitched "sawing" sound off and on, affected by throttle application, dissappears on decelleration. Pulled over and discovered Pinion nut loose. Tightened with 1/2 inch ratchet till "cranked" but not killed. Noise changed pitch but persists.

 

Crush sleeve? Any usual suspect parts? Repairable in parking lot?

 

Local JY has a 75 620 axle for 90 bucks. I know they are different. Will the third member or any part off of it help my 71 521 rear axle problem?

 

friesens4@hotmail.com .... I've got my iPhone.

 

Help would be greatly appreciated

[banzai510(hainz)]

there has bee a few post of swapping 3rd memebers to better diff gear ratios

 

I heard tha 620 axles are a diffent length but maybe not noticeable in a truck anyways if swapping the whole diff.

Datzenmike will know for sure. maybe there is a spline count difference between the gear ratios.

 

looking at my motorsport cat they say there is 3 different sets

 

more or less I dont KNOW!!!!!!!!!!

[ppeters914]

Interesting that almost the same issue reported by a local roadster owner earlier today.

 

Those in the know (I definitely don't) say "it sounds like a pinion/ring contact or pinion bearing problem" and to replace instead of repair. Of course, they're not traveling.

[69FJWagon]

Hey Denver the third member or drop out as some call it will work out of the 620, I have a third member from a hardbody in our 521 with the driveline pinion flange from a 720 to keep the overall length of the pinion the same for the driveline... I went with a 3.90 gear but there are a good range of ratios that make it easier to drive down the freeway (3.70 & 3.90)

 

 

Clayton

[denveratsun]

Hey Denver the third member or drop out as some call it will work out of the 620, I have a third member from a hardbody in our 521 with the driveline pinion flange from a 720 to keep the overall length of the pinion the same for the driveline... I went with a 3.90 gear but there are a good range of ratios that make it easier to drive down the freeway (3.70 & 3.90)

 

 

Clayton

Wow....that's all good stuff. Thank you guys so much for chiming in. They all look the same on the outside from what I saw today at the junkyard. They had two 720s and a 620. I would have loved to have gotten any of those third members,(no matter what ratio they were) but since the duche wads couldn't start their forklifts, I got nothing. I found a 71 at a different yard that I will get tomorrow. I'm going to hope to stick with similar gears since I have the five speed And need all the torque I can get... Thanks again.

I'm off to "search" previous threads for gear ratio info... Just in case i can find a little deeper first gear somehow. I can go 90 all day and that's plenty of top end for me:)

[Farmer Joe]

yeah there was just a post where datzenmike posted up all the 3rd memebers and ratios thatll work for ya.

 

H-190

All '72-'79 620 4.11, 4.375, 4.625 will fit.

All '80- '86.5 720 2wd 3.364, 3.70, 3.889, 4.11, 4.375 will fit.

The '82 200sx manual tranny has a 3.545 that will fit.

 

if your trying to find out what the ratio is, its hard with a 620, but 720s from like 81 and up have a tag on the inner side of the passenger fender almost by the firewall. the tag will have the engine, trans and rearend code. the rearend code in the 720s should be "HLxx" and the xx will be 2 numbers referring to the ratio. example, HL41 would be 4.10s, HL38 would be for 3.889 (3.90 rounded up), HL43 for 4.37s, and so on. hope you find a better 3rd member. happy hunting!

[datzenmike]

Your 521 will have an aluminum case diff. but the later 620 steel ones will fit too. Some of the early 620s with L16s also had aluminum cases and the standards were 4.375 while the automatics were 4.625s. After Sept. '73, all carriers, standard and auto, were cast steel and 4.375 through '79 with the exception of the '79 standards which had a 4.11s. As stated the 720 have an aluminum tag under the pass side hood hinge on the inner fender with the rear gear ratio listed. The look like this:

 

 

 

 

 

 

 

 

 

.

[wht620]

30 miles east of Barstow....drove all the way from Denver perfectly....rear pinion is makin noise. Getting worse. High pitched "sawing" sound off and on, affected by throttle application, dissappears on decelleration. Pulled over and discovered Pinion nut loose. Tightened with 1/2 inch ratchet till "cranked" but not killed. Noise changed pitch but persists.

 

Crush sleeve? Any usual suspect parts? Repairable in parking lot?

 

Local JY has a 75 620 axle for 90 bucks. I know they are different. Will the third member or any part off of it help my 71 521 rear axle problem?

 

friesens4@hotmail.com .... I've got my iPhone.

 

Help would be greatly appreciated

hi denveratsun, which local J.Y did u found datsun parts im local, from the rocky mountains and im having a hard time to find parts for my truck as well(620)any info will help me alot :) so i can have my truck running.

[denveratsun]

Wow guys.....thanks again for all the info. Mike...I can honestly say that I am not shocked by your knowledge on the subject.

 

So yesterday I was talking to Madness about this little problem and we were comparing Toyota axles to the Datsun units. I decided that after the initial roadside "tightening" of the pinion nut I needed to go back and "crank on it". So I did:)

Its quieter now and the "sawing" noise is gone. The high pitch whine is way less. I feel like I have at least bought myself some time withbthus rearend. I am in Paso Robles area driving up 101 to the Monterey Bay. There is a bunch of Junk Yards up in Moss Landing and one of them has a 71. I am thinking that's the ticket fir now.:)

 

hey wht620.....check with Colorado Salvage. They are off of Santa Fe south of Hampen. The yellow 620 is in the very last row on the south side of the truck section.

 

I got pics comin.....I just can't do Photobucket, Ratsun, pictures and texting while I'm driving. That's just too much.

[zerow]

I just can't do Photobucket, Ratsun, pictures and texting while I'm driving. That's just too much.

Don't get caught - they crucify you for things like that here in California... :o

[denveratsun]

Man....I know about Cali they will string you up! :)

 

after the last tightening of the pinion ( I know it's not a "fix" but it's better)...it has quieted down some. All I can find out here is 720s with low 3s for gears. I just found a 3.8 third member.

Good grief that's gonna KILL my low end.

 

Ummmmmmmmmmmmm.................:(

[datzenmike]

Only the 'Mileage Option' '84-'86 720 had the 3.364 diff. Totally don't understand Nissan on this one. They mated that rear to a Z20S motor with 9.0 to one compression and 5 speed. I guess it works but must have abysmal acceleration.

[denveratsun]

Well gents, after all those junkyards I finally found a good diff out of a 78 620 KC with an auto trans. Bolted it in ( with a couple remaining questions) and drove all the way to Colorado. I will post pictures :) and ask my remaining questions when I get home.

[datzenmike]

A: it's a 4.375 ratio

 

A: yes, the same as what was in your 521. :D

[denveratsun]

A: it's a 4.375 ratio

 

A: yes, the same as what was in your 521. :D

 

Hey...it seems like its slugish off the line. I mean...granted...its an L16 right :rolleyes:

 

But I was wondering...what if it were out of a 79 instead? Seems like it may have had a production date of 8/78...if I can remember rightly....it did NOT matter to me after that many Junk Yards with no luch I was freegin pumped that they even had one at all!

[datzenmike]

If it was from an automatic it's still a 4.375. Only the '79 standards had the 4.11 ratio.

 

Do NOT tell me you stuffed it in without looking on the outer edge of the ring gear for the ratio!!!! :lol:

[74datsun620]

Its great that you got her fixxed and made it home, Sow does this mean I can repace my steel diff. for an alumin. diff. on 1974 620 Datsun.

[denveratsun]

Haha....yeah Mike....I did. The number was the same. The weird thing was that it didn't say anything like 4.37 or 4.11. The last number on both of them was 35.8. Sooooooooooo.....yeah, I looked.:)

 

and yes....you can polish the crap out of an aluminum diff and run it!

 

Thanks again for all the help. Pics coming in a "Road Trip" thread tomorrow.

[datzenmike]

Divide 35 by 8........ :lol::lol::lol::lol:

[denveratsun]

:blink: ............. :unsure: ................ :rolleyes: ................. :lol: