'85 720 Transmission oil change? Need breaker bar? - Nissan Forum
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post #1 of 4 Old Jan 21st, 2011, 08:34 PM Thread Starter
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'85 720 Transmission oil change? Need breaker bar?

Hey guys, quick question that i'm sure nearly all of you can answer but i'm not a real car guy yet (although i'm trying to be one). i am trying to change the manual tranny fluid (using GL-4) on an '85 nissan 720 4X4. I bought the fluid, drove the car like chilton said to so the oil was warm, then got underneath to see this:

So here are my questions:
1) the truck manuals I have kept showing the level plug on the drivers side but I think mine is on the passenger side. Is what my arrow pointing to the filler hole?
2) it looks like I need a 1/2" breaker bar for the drain plug. That is the manual tranny drain plug isnt it?
3) how concerned should i be with the amount of oil that is on the outside of the tranny case?

Now up closer to where the tranny meets the engine, it looks like I have some gaps and missing bolts. Is this a big issue? To be honest when I get under the car i am never really sure what I am looking at. I want to change all the gear oil on the truck, I am just not confident i'm locating the right things. I.E. transmission, transfer case, front differential, steering gear, rear differential (about the only one I know).

thanks for your help guys. take care.


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post #2 of 4 Old Jan 22nd, 2011, 04:36 AM
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On the older trucks, the fill plug was on the right side. On Hardbodies, it's on the left. 17MM wrench should work on the fill plug; 1/2" breaker bar and extension on the drain plug...and yes, that is the drain plug. Looks like the switch on the right side of the trans is leaking, and the other leak could be the trans extension housing rear seal; hard to tell with that picture. The gap isn't a real big issue, but looks like you have an oil leak, possibly from the rear main seal or oil pan gasket...or both.
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post #3 of 4 Old Jan 22nd, 2011, 08:57 AM
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A tip: always take out the fill plug first, that way you don't get the drain plug out and then find the fill plug is hopelessly stuck and your car undrivable.

Soak the drain plug repeatedly with liquid wrench for a couple days if possible before attempting to remove. If you find it's so stuck you can't get it out without stripping it, you can replace 90% of the oil using a mityvac through the fill plug.
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post #4 of 4 Old Jan 22nd, 2011, 03:07 PM Thread Starter
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Thanks for the verification. I will get it up on ramps in the next few days and try to get this done. next time I change the motor oil, i'll replace the oil drain plug and gasket. It the leak is also from an engine seal, i'm afraid that is beyond my abilities. Is there some kind of threadlocker or gasket sealant I could put on the bolts or flanges that is recommended to keep leaking from the plugs? Would I have any issues taking those sensors out, cleaning them up and putting them back in to prevent them from leaking? And maybe putting some gasket sealant or threadlocker on them?


Thanks for the tip, i will definitly make sure I can loosen the filler plug first. I have a feeling that one shouldn't be a problem since it looks pretty wet with oil as is. I'll start coating with liquid wrench today.

Your expertise is always appreciated. Thanks.

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