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1966 datsun 520 transmission


wayno

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Wano is this the tanny?

 

unknown003Large.jpg

 

I think it's for filling with oil. Take a look at the picture... the 'top loader' forks (top front) are likely splash oiled but look further back just below the shifter. How does the shift fork/shift lever get lubed??? I think there is a small cavity there that has to be filled with oil.

 

Bet MKlotz would know.

.

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It looks like the one I am talking about except for the mounting holes for the rear tranny mounts, is that how the 65 L320 mounts, like the column shift tranny does? My 66 tranny mounts like the all the J13 521 trannys do. So tranny fluid goes in the shifter stick hole? Is that how it is filled? Yes, that looks like the tranny I am talking about.

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Yep, thats the plug i was talking about. When I removed mine, nothing came out. I think the gasket around the little pan below mine has been leaking. I went ahead and replaced the crush washer on the 'drain plug,' and filled the compartment thru the shifter hole until it was just above the moving parts. This is all similar to refilling the turret oil in my '92 miata.

 

I took it for a drive, and its shifting way smoother. Of course though I can't tell much, since I changed the rest of the tranny oil at the same time. The old gear oil in the rest of the tranny looked fine, and was likely replaced recently, but I replaced it all with fresh Valvoline Synthetic 75W-140. So yeah, getting in and out of first is way easier than before, and generally less crunchy all around. Still not quite as smooth as my miata or BMW, but it never will be, it's a truck.

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and Datzenmike, that pic looks exactly like the tranny in my truck (a late '65 L320 with floor shifter and J13 swap), which spawned this conversation. Mine looks nice and clean all over, like it may be pretty fresh, or at least just cleaned up really well. Do you know the name/designation of that tranny, for future reference for me?

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I am not sure if your supposed to use synthetic oil in these transmissions long term, someone was saying that it was not good for yellow metal(brass syncros) in these old transmissions, but there was some number like GL5 was bad and GL4 was good. Sometimes I read so fast that I don't understand correctly though.

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GL4 = good, GL5 = bad.

 

Synthetic is ok is yellow metal compatible. Only down side to synthetic is it is so slippery it will leak past old worn seals and gaskets where the 80w90 does not.

 

 

I know about the whole GL-4 vs. GL-5 thing, and have been researching it a bit too much over the past couple of days. I used Redline MTL in my BMW last time, but can't find it locally here. Apparently it's not really an issue with new formulations of GL-5, though. Pretty much all of the GL-5 oils have been yellow metal compatible for the past couple of years. The guys on the bobistheoilguy.com forum are incredibly picky about this stuff, and go into great detail. It doesn't hurt to dig thru the facts about each companies formulas, though. I checked up on Valvoline thru some searching and company responses, and they're good for yellow metals.

The only real issue is in smoothness of shifting because some gear oils are made more for differentials, and not manual transmissions (so thats why some guys get crunchy shifting with GL-5 oils, and not GL-4). The Valvoline did say it was MT-1 rated and could be used in manual transmissions. It gave me nice smooth shifting in my miata when I put it in that last night, so I went ahead and put some in the truck. All seems well.

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Apparently it's not really an issue with new formulations of GL-5, though. Pretty much all of the GL-5 oils have been yellow metal compatible for the past couple of years.

 

This contradicts everything I've heard about extreme pressure GL5 differential vs. GL4 transmission oils. GL4 oils must pass a minimum copper corrosion test to be rated GL4. GL5 oils contain at least twice as much sulphur compound additives to increase it's anti scuff properties and because it is not intended for use in transmissions with copper/brass synchros is not even tested for this. It may or may not say 'yellow metal compatible' but to be safe must have passed an ASTMD-130 test of copper corrosion. Nissan is quite clear about GL4 oils for their standard transmissions.

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This contradicts everything I've heard about extreme pressure GL5 differential vs. GL4 transmission oils. GL4 oils must pass a minimum copper corrosion test to be rated GL4. GL5 oils contain at least twice as much sulphur compound additives to increase it's anti scuff properties and because it is not intended for use in transmissions with copper/brass synchros is not even tested for this. It may or may not say 'yellow metal compatible' but to be safe must have passed an ASTMD-130 test of copper corrosion. Nissan is quite clear about GL4 oils for their standard transmissions.

 

I really don't want to dig back thru the threads I was looking thru the last couple of days (nor am I personally an oil expert that can speak intelligently about this). But my understanding was that the whole GL-4 / GL-5 rating is obsolete at this point, and they don't even have a rigorous test for the GL-4 anymore. The GL-5s are still well-tested, and now have several other compounds in them that can counteract any yellow metal corrosive effects, and the sulphur compounds as well have been changed to something better.. . think they said the particular phosphates used had more to do with the old corrosive effects... I dunno man, but dig up some more research if you like.

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I really don't want to dig back thru the threads I was looking thru the last couple of days (nor am I personally an oil expert that can speak intelligently about this). But my understanding was that the whole GL-4 / GL-5 rating is obsolete at this point, and they don't even have a rigorous test for the GL-4 anymore. The GL-5s are still well-tested, and now have several other compounds in them that can counteract any yellow metal corrosive effects, and the sulphur compounds as well have been changed to something better.. . think they said the particular phosphates used had more to do with the old corrosive effects... I dunno man, but dig up some more research if you like.

 

OK, so I looked back a little more. I think I found the webpage you might be referring to about the ASTMD-130 copper test, and the information on it is dated 2007, whereas the stuff I've been looking at is 2009 or later. Maybe you've got more up to date information than I'm thinking, I don't know.

Apparently the newer Valvolines (in just the last couple of years) have inactive sulfate in them, which is non-corrosive, so that's part of why I went with them (always had good luck with Valvoline oils in the past too, so that helps).

Mobil 1 does not make similar claims, and warns that their GL-5 oils might harm yellow metals.

 

In any case, judging from the receipts on my truck, I bet the gear oil in it was put in around 07 to 08 (before sitting relatively idle for a couple years), and it sure smelled like sulfur, so I'm glad I got it out. The trucks shifting way better now. Unless I hear that Valvoline has been lying, I think I'll leave it in there.

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I think also that newer trannys can run with GL5 and there is less demand for something run in old Jjap cars just like most cars use roller tappets and can run with little or no ZDDP. As ZDDP levels drop we owners of old Jap flat tappet motors are going to grind our cams away. I'll keep an eye out for more info, for sure, but for now I go with factory recomendation oils.

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I think also that newer trannys can run with GL5 and there is less demand for something run in old Jjap cars just like most cars use roller tappets and can run with little or no ZDDP. As ZDDP levels drop we owners of old Jap flat tappet motors are going to grind our cams away. I'll keep an eye out for more info, for sure, but for now I go with factory recomendation oils.

 

I know about the ZDDP issue too. I think the risk is a little over-blown, but I'll still be careful. I use Valvoline VR1 20W-50 in my BMW, which is chock full of ZDDP since its technically a 'racing oil.' I do race that car quite a bit, and like the performance of that oil anyways. For my Datsun, the solution I found was to use regular 10W-40, and add a bottle of the STP blue engine oil additive. They now add lots of zddp to the STP blue, and according to STP it's about 4 times as much what used to be in 1 quart of oil... so, one bottle of that should cover it.

 

I might consider some Redline MTL if I find it reasonably priced, but I'm kinda in the middle of nowhere here. I put Redline MTL in my BMW, but that's when I had a Redline store down the street (and I had an employee discount), but again that car gets raced so it takes some serious abuse which justifies using expensive oils.

I also think the sulfide problem is a little over-blown, as I'm sure there are lots of non-internet forum guys that have old cars and use off the shelf gear oils in them. I would think the major oil companies would do anything they can to prevent such widespread damages to transmissions, and thus protect their reputations. It's not just old jap cars that have yellow metal synchros. I've had to go over this with my BMW, and I know they're in Porsches, and tons of other cars. They seem to be in modern cars too. I've seen owner of modern Subarus looking for GL-4 and debating this, newer Nissan owners, and owners of many other modern cars. Is there really an alternative metal that's not yellow that can be used in synchros for manual transmissions? I've never taken that many transmissions apart, but it seems like they're always brass/bronze.

It shouldn't require this much work and debate to decide on gear oils. So, I'd like to think at least Valvoline has figured this out by now and found a way around it, or at least that's what they claim with their inactive sulfates.

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Back to the original topic! So, most of the oil that I put in the shifter platform leaked out overnight onto my garage floor, yaaaay. I think it's leaking all around the mini-oilpan that sits on the bottom of it (and above the transmission itself). I suspected that anyways. Maybe I just overfilled it, but I'll check later to see if there's any at all left inside.

I'm gonna bet its near impossible to find a gasket for this obscure thing. I'll probably have to make my own gasket, or just use my own sealant. Might be a pain too to access the bolts around the driveshaft.... Probably won't be my highest priority of things to fix for a while, though.

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Back to the original topic! So, most of the oil that I put in the shifter platform leaked out overnight onto my garage floor, yaaaay. I think it's leaking all around the mini-oilpan that sits on the bottom of it (and above the transmission itself). I suspected that anyways. Maybe I just overfilled it, but I'll check later to see if there's any at all left inside.

I'm gonna bet its near impossible to find a gasket for this obscure thing. I'll probably have to make my own gasket, or just use my own sealant. Might be a pain too to access the bolts around the driveshaft.... Probably won't be my highest priority of things to fix for a while, though.

 

You might be better off than I am, when I removed that plug, it emptyed itself, of WATER, my seal is good though, I guess it sat outside to long, maybe.

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  • 4 years later...

For clairification, the fill capacity is:
64 fluid ounces to main fill hole
8 fluid ounces to shift lever hole (Edited due to subsequent information provided that shift lever hole is not a fluid filled cavity.)

My transmission was completely dry from draining a couple of years ago. Using the above measurements, a bit of fluid will overflow the holes, so keep a drip pan or tray below the vehicle.

Remember to check the levels after 100 miles of driving.

Keith

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No FSM recommends the shifter being used to fill the transmission. Transmission is full when oil is level with the proper fill hole on the side. The 71B holds 2 liters or 67.62 fluid ounces. You may be able to cram more in but risk over loading the rear seal or dripping out the top vent.

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I don't believe that the plug in the back of the shift-mechanism casting is for adding lube. I also don't believe that the plate and gasket in the rear of this housing (directly inder the shift lever) would hold lube very long. The shifter shafts in the housing should get assembled with grease or re-greased whenever the top casting is removed. I believe that the plug is for initial machining and assembly/dis-assembly procedures. Here is a photo,from the rear, of the housing off and upside-down:

 

320%20Floor%20Shift%20Trany%20Top%20Cove

 

It's been over a year that I had the cover off and can't recall what I deduced from cleaning, lubeing, and re-assembling the cover. As for filling the trany gear cavity, that is done and checked in the dipstick hole in the left front corner of the gearcase. Don't know bout the 520 or sedans, but the 320 has about a 2 1/2" diameter rubber plug in the floorboard of the cab for accessing the dipstick.

 

Steve

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The top-loader transmission was used in the late 320 and in the 520 production (started in spring 1965, I think) till September 1965. It was then replaced with the four-speed trany with the stamped steel 'flatish' pan that covered the bottom of the transmission. The guts were loaded into this transmission from the bottom. The shifter is about 4-5 inches further back on the bottom-load trany; almost to the back end of the tailshaft housing. I guess at that point the floors of the cab got a different stamping to allow for the transmission change.

 

steve

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Keith,

If you're talking about draining the rear cavity under the shifter, see if you can reach up, either in front of or behind the tailshaft mount with an end-wrench and loosen a bolt or two that hold the sheet metal plate on and pry the sheet metal cover away just a little. You'll probably get an oil bath. If the oil is not leaking out, it shouldn't hurt anything. The gasket on the cover will probably start leaking over time and oil will probably drip out wherever you park it eventually. On a 320, the floor tunnel panel could be taken out with about a dozen screws and the draining done from the top.

 

Don't know ablut you're 520. They have a solid floor, don't they??

Steve

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Steve,

Would it be possible to remove the plug in Post #1 to let the fluid drain? (I could jack up the front of the vehicle to allow for a slope to the transmission.) I prefer not to loosen the cover plate, as I am fearful of not getting a good seal when I re-torque it down.

 

The floor of the 520 has

1) One cutout located directly above the transmission fill plug.

2) One hole directly above the transmission where the shift lever passes through.

 

Keith

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Sure, Keith. The plug would let most of the lube out. It wouldn't hurt anything for the lube to be in there, it would eventually leak out, I think. It'd probably shift smoother with the lube in the cavity. I just greased the heck out of all the rods & fingers when I had the housing off and opened up.

 

Steve

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