Transmission drain plug removal?

Dealing with all subsystems specific to the diesel powered Datsun-Nissan 720 pickup trucks.

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bellavesus
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Location: asheville nc

Transmission drain plug removal?

#1

Post by bellavesus »

What sort of tool to use on the square plug? I went to NAPA yesterday and the men all basically told me I was crazy, that such a plug did not exist, and were therefore of no help to me in figuring out how to remove this plug. What to use on this thing? I need to replace the oil BADLY, its black as hell and VERY low.
Thanks,
J
live to ride...
81' 720 king cab SD22 w/GP problems
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asavage
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#2

Post by asavage »

First, make the hole very very clean. I dig out all the grease and dirt using a No. 0 screwdriver blade or similar.

Then you can use either a 1/2" breaker bar, or a 1/2" ratchet. Why the ratchet? I find that the material is a bit harder on the ratchet spud than some breaker bar material, which can help prevent stripping out the plug.

The plug must be tight, it will leak if not tightened pretty tight. It's also got a magnet on the end of it, so it's "special". If you haven't had it out in a while, you will find significant steel filings on it.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
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kassim503
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#3

Post by kassim503 »

If the ratchet/breaker bar will not be missed, slip a 2-3 foot pipe on the end of it and pulllllll or pussshhhh. They sure as hell dont like coming out easy.

If space permits and if you have pneumatic tools, a impact wrench makes quick work of this, but give the other method a try first, everytime I lazy myself down enough to do this I feel like im going to crack the threads and the case around it. Anybody have any words of wisdom on this?
'83 maxima sedan, l24e, a/t, black

227K SOLD 6/7/2012
moose60
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Location: Seattle WA

#4

Post by moose60 »

The next time I take min out, I'm gonna teflon tape the threads and not put it back in super tight.

I too have been pretty sure that something was going to strip out and leave me totally screwed.
Byron

82 Datsun 720 KC SD22

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asavage
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#5

Post by asavage »

The threads don't give, but the square socket does. I've had to cold-chisel and drill one out. That's why you want to have the socket very clean, so the square end can seat completely.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
davehoos
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#6

Post by davehoos »

a common method is to weld a bolt to the stripped plug.grind 4 flat side in the shaft and hammer into the plug,then weld in place.

the heat from weld will loosen the plug.

the drain plug is available with a square head like some filler plugs.
but always manages to get damaged.
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philip
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Re: Transmission drain plug removal?

#7

Post by philip »

bellavesus wrote:What sort of tool to use on the square plug? SNIP I need to replace the oil BADLY, its black as hell and VERY low.
Thanks,
J
How would you know that the transmission is low when you have been unable to remove the side plug?

With really BLACK oil, you are more likely to have engine leaking loose.

Al has my agreement to use long wrench.

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-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"
davehoos
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#8

Post by davehoos »

a large adjustable wrench is best for the filler plug.heat it if it wont turn easy.it has grown in or been loctite.
12-18 inch shifter.

A tool is availabe for transmission/axle plugs.
normally 2 types,1. male,2.female[socket].with 4 and 6 sided tools.
looks like a bone with 4 different size/shape tools at each end.

never bothered to buy one.

vry slow but you can suck out the oil through the filler plug with a small pipe.[brake line].
WCJR31 Skyline.3.0 manual.wagon
R31 SKYLINE/Passage GT/PINTARA
LPG Ford Falcon 99-06 93 Disco
Local Shire Southern Zone Mechanic.
bellavesus
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Location: asheville nc

#9

Post by bellavesus »

Thanks all for the tips, after i asked the question i wen tout there and tried the 1/2 ratchet just as a matter of course, and it fits. Good point on cleaning it all out before i try to remove it, i was planning on adding some teflon tape wen ti put it back in so as not to have to crank it so tight. I have had the side (filler plug) out, just not the drain plug. Worst case scenario, i was going to suck out all the old fluid with a siphon through the filler hole. Hopefully that will not have to happen....
live to ride...
81' 720 king cab SD22 w/GP problems
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philip
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#10

Post by philip »

When the "bottom" plug is pulled out, then ALL of the oil falls out.

The total replacement 90wt oil is GL3 and/or GL4 oil that is NOT "hypoid" type. Total of 2 quarts (USA). When you do use the hypoid version, the gear tends to seems a little notchie.
Last edited by philip 14 years ago, edited 2 times in total.
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"
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asavage
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#11

Post by asavage »

I spray a whole can of brake cleaner in the fill hole, with the drain plug out, to try to encourage some more crap to come out. I also spray up in and around through the drain hole. The first time you change the oil in an FS5W71, it's pretty bad.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Carimbo
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#12

Post by Carimbo »

moose60 wrote:The next time I take min out, I'm gonna teflon tape the threads and not put it back in super tight.
I've had good results with anti-seize paste. Don't use too much; it will end up on EVERYTHING.
plenzen
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Location: Cochrane Alberta Canada

#13

Post by plenzen »

Philip sent me this link for cleaning the remaining dino oil out of my transmission. (brake clean) I noted that there were a couple of suggestions as to how to remove the drain plug that was really really tight. It appears to be a pipe thread which means it is tapered. Teflon helps you wind it in further for a tighter seal but not actually a sealant.
Back in the day ( 1970 ) when we used to run across these plugs, and other pipe fittings that had tapered threads on them, most times if you tried tightening them slightly just to get them to move the they would then back out easily. Most times you could tighten them at the onset but not back them out. ( Dont know the science behind it but it works) We also used some stuff called PST made by Loctite. Pipe Sealant with Teflon. This was a hell of a sealant and also allowed the fitting to be removed years later. Great stuff!! Just a thought that is all.
Last edited by plenzen 14 years ago, edited 1 time in total.
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Problem with being retired is that you never get a day off.
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kassim503
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#14

Post by kassim503 »

i actually use a 1/2 inch impact gun with the pressure cranked to as high as the compressor can go to loosen these plugs when im too lazy to take them out by hand or the threads have fused a bit. Its probably not good, but ill also get a heart attack pulling on it. I also reccomend a breaker bar with a long pipe and closing your eyes while pulling in case something shatters.
'83 maxima sedan, l24e, a/t, black

227K SOLD 6/7/2012
plenzen
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#15

Post by plenzen »

I think that the cast iron plug into aluminum also has something to do with this and the dissimilar metals thing etc. The tightening method has always worked for me though. I think that the taper that is inside gets crud collected around it and bonds with the casing and does not allow it to back out. Acts like a wedge. If you try and tighten it then it pushes it inside and away from the threads. That is all I can think of

Paul
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN
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