1974FJ 55 transmission and transfer case fill and drain bolt locations and Mobil 1.

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I was wondering if someone would be willing to take a moment to just confirm the drain and fill locations for the transmission and transfer case on my FJ. I read through a long post on changing the transfer case gear oil on here last night but I don’t think it was appropriate for my particular FJ. Also I’ve also been trying to find somewhere that has the requisite drain bolt washers/gaskets if someone knows of a reliable location.

I plan to use mobile one full synthetic 75W 90 for both differentials, transmission, and transfer case. Am I missing something here? That seems to be appropriate for all three it is hard to beat mobile one.

Took the time to try and clean up the bottom of the old girl today she’s not 100% but she’s getting there. She was a dirty girl.
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1MOA

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You are correct on the fill/drain locations. I would also suggest you get a FSM manual ( you can download it from mud) and also suggest rather than go synthetic you just run regular GL4 oil as you already have what looks to be a few leaks from both cases.
Pay close attention to the old oil and see if the seals have given out and monitor it afterwards with regular checks to see if it is leaking out or between the cases.
 
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You are correct on the fill/drain locations. I would also suggest you get a FSM manual ( you can download it from mud) and also suggest rather than go synthetic you just run regular GL4 oil as you already have what looks to be a few leaks from both cases.
Pay close attention to the old oil and see if the seals have given out and monitor it afterwards with regular checks to see if it is leaking out or between the cases.
Is there a reason to use regular gear oil versus synthetic due to the leaks or is it due to price?

I was planning to have the transmission and transfer pulled and ALL gaskets replaced this year.

S
 
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yeah syn is a waste here....and really probably not the best for them....just good ol fashioned gl4 is all that is required.
So if this was your pig would you pull everything and replace all the gaskets or just drain and refill with GL4 and top off as needed between changes?

If I pull the drain and fill plugs I imagine I am going to need to replace the plug gaskets each time correct?
 

1MOA

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Your trans and transfer case were built for conventional oil with certain additives that GL4 gear oils have. Synthetics are less “bond able” to surfaces and flow easier so if you already have a leak syn fluids will run through them quicker than conventional oils.
You are gaining nothing and actually are hurting older machinery switching the lubricant.
 
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Your trans and transfer case were built for conventional oil with certain additives that GL4 gear oils have. Synthetics are less “bond able” to surfaces and flow easier so if you already have a leak syn fluids will run through them quicker than conventional oils.
You are gaining nothing and actually are hurting older machinery switching the lubricant.
I just got done reading this….


So your point makes total sense. I will shop for an SAE 90 GL4 gear oil for the transfer case and transmission. I will keep an eye on the leaks and plan to have the trans and transfer pulled and all seals replaced at some point this year. Would you go up slightly on the differential viscosity given that I live in SC? Really hot here in summer….90+…however in all honesty I probably won’t drive it much during the day in the summer.
 

WarDamnEagle

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I run synthetic in mine and disagree that it will harm the internals as long as you buy the right spec. I'm a huge fan of Mobil 1 for engines but I run Redline synthetic in gear applications. They make an MT90 which is a GL4 synthetic that is great for these older manual transmissions. Use that in the Transmission and transfer case and their 75W90 in the diffs. You can also use the 75W90 in the transfer case if you want. I'm sure you know this but nobody has mentioned it yet, open the fill plugs before you open the drains.....just in case the fill plug gets stuck.
 

1MOA

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You are fine running a GL4 75W90. if it's leaking no point in running high dollar synthetic that is going to end up in the dirt. The important point is to get it cleaned out make sure the t-case seal is not leaking to the transmission and put new appropriate lubricant in there.
If you open up the transmission filler and oil comes flowing out it is a very good chance the seal(s) between the two have failed and the fluid is passing from the tcase to the transmission. Fill each appropriately and check them both for oil level after a interval and see if the transmission is now over filled and the t case is low. (It might be possible the oil is just leaking out of the other gaskets as well judging from your pictures)
If you are not in a position to get the cases repaired there is a "fix" that will buy you time in the form of a hose that will return the oil back to the T-case.
Thread on it
If you want to buy it:
 
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You are fine running a GL4 75W90. if it's leaking no point in running high dollar synthetic that is going to end up in the dirt. The important point is to get it cleaned out make sure the t-case seal is not leaking to the transmission and put new appropriate lubricant in there.
If you open up the transmission filler and oil comes flowing out it is a very good chance the seal(s) between the two have failed and the fluid is passing from the tcase to the transmission. Fill each appropriately and check them both for oil level after a interval and see if the transmission is now over filled and the t case is low. (It might be possible the oil is just leaking out of the other gaskets as well judging from your pictures)
If you are not in a position to get the cases repaired there is a "fix" that will buy you time in the form of a hose that will return the oil back to the T-case.
Thread on it
If you want to buy it:
All great points. I have decided to use the GL4 GO.

But please correct me if I am wrong. In reading the FSM the gear oil in the differentials, transfer, and the tranny are the same.

So when you mention being aware of fluid transfer from one to the other via seal failure
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you mention because of the concern for the incorrect volume differences versus incorrect fluid type correct?

I plan to drain, inspect and fill my differentials today. They are not leaking. I also plan to check fluid levels and top off as needed the transfer and transmission.

My local Toyota dealer hasn’t had 55 in their shop and they are dying to see it and have offered to give her a complimentary top to bottom review with triaged repair recommendations.

So she’s headed up there sometime this week for a few days. I’ll let them sort out the leaks on the drive train for me.
 
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The concern with the transfer is, it can dump enough of its oil into the trans that it runs low enough to smoke bearings.
I checked it today and the trans was pretty low. I corrected it and will definitely keep an eye. The diffs were good and clean, the trans was clean so that’s good.

Thanks for helping.
 
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Bit of a side note. Anyone know where to find these fill and drain plugs? My differential plugs are all a little beat up, might as well make everything in the driveline match.

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73FJ40

After another night of rust removal!
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