Transmission fluid check procedure (Tremec 3160)

[murick]

Today I went ahead with the transmission fluid check on my Mach 1 with Tremec. I had the fluid fully replaced right at the beginning (now having cca 10k km) at the shop, which later turned out to be not that convincing. So I thought I should give it a try, the procedure is even clearly described in our manual.

The user manual for the transmission fluid check (for Tremec 3160) says:

1. Clean the filler plug.
2. Remove the filler plug.
3. Start the engine and allow it to idle for two minutes with the clutch engaged.
4. Add fluid through the filler hole.
5. The correct fluid fill level is 0.0–0.1 in (0–3 mm) below the bottom edge of the filler hole.
6. Install the filler plug.
7. Tighten the filler plug until you feel a strong resistance.

I have not found any reference to this exact procedure anywhere (neither on this forum, nor on some YT videos I checked before). There was one guy recommending idling after the full change with the plug closed. I guess it might have been related to/inspired by this check (apart from the plug).

I did it exactly by the book, until point 3) where I put in the 1st gear (with the wheels of the ground). Once I realized my mistake and with few puddles of the fluid spilled from the open filler plug hole, I put in neutral, but it either did not help, or there was some inertia in play, either the fluid was still coming out of the plug hole.
Unfortunately I cannot say if it was because of my mistake, or it would spill anyway even in neutral.

After that, I closed the plug, let the car idle again (on neutral this time) and then started to fill in the fluid. Unfortunately I only prepared for a check and eventual small addition so have only 1L bottle of the fluid by hand and only large syringe for filling and until the last shot I was not sure if I ever would have enough to cover what I spilled earlier. I was lucky!

I cannot say if there was enough fluid originally, because when I opened the plug, nothing was coming out, but there was some oil film inside the hole and it is almost impossible to tell just by touch. I thought I did not spill the whole litre, but after I put almost the whole litre back I could not really tell.

Anyway I wonder if anyone ever tried this with the open plug and had a better success.

The other point I was not sure about was how much should I tighten the plug. When releasing it it felt pretty tightly screwed in, with some red sealant clearly visible on the exposed part of the plug thread. But when I was screwing it in, it felt I might actually screw it through, because I screwed it more than it originally was, yet it did not feel as snug as it originally was. The sealant was also coming off once I started to go deeper.

It looks like there is actually no limit and the thread should catch on the sealant. I guess, next time I might give it few loops of teflon thread.

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[AZ_Ryan]

I'd be curious to know if anyone's came low from the factory.

 

[Optimum Performance]

Tremecs typically fill to the bottom of the hole. I think you may be trying to hard. It should be near the hole and move on.

 

[murick]

Tremecs typically fill to the bottom of the hole. I think you may be trying to hard. It should be near the hole and move on.

I would have believed that the filling point was relatively well established - even the Ford manual was pretty clear on that. It basically said fill it up to the hole. Yet there are videos on youtube recommending overfilling it, without any explanation.

Having the trans idle with open(!) fill plug is even worse. Since not all Tremecs come with the external cooler and even those which do can differ by having or not an active pump, the question is real and circulating best practices without context can be as misleading as helping.

 

[Optimum Performance]

Fill it to the bottom of the hole off. If you have a cooler run it, shut it off and re-check it.

 

[murick]

Just to recap here my recent observations.
I found a doc on this forum, which describes the draining and filling procedure for Tremec 3160 (though I did not find the post - it popped out on google), which I attach to this post.

Running the transmission to fill the cooler after the draining makes sense, if the cooler can be drained (apparently it can).

Running it before the check would make sense if the fluid from the cooler can somehow "fall back" into the transmission if the trans was not run for some time.

This would be something that people who opened the filler plug without running the transmission first should observe as the fluid spilling from the fill plug. I cannot verify that since I have a 30 min drive to the place where I can lift the car, so I never work on a cold car.

I did the second inspection during the last weekend, by running the transmission first (on idle) for 2 minutes and then opening the filler plug. Apparently I filled it ok the last time as I observed a small overspill from the hole.

I tried to "overfill" it, and then waited for the spilling to stop, only to measure that what I put there, I caught into the pan after. So this part turned out ok.

The other tricky point was how to torque the filler plug. The thread used there is apparently not the regular thread, but a tapered one (not sure about the English nomenclature) and that more you screw it in, more tight it become but also more "adapted" it become.

It looks like if you overtighten it, you may need to screw it in more the next time to get it to the same torque.
On the other hand, it also looked (felt) like once it "bites" it requires distinctively higher torque to continue, or to unscrew it. Especially unscrewing the plug felt like needing much higher torque than I gave it two weeks ago when I screw it in.

The thing is further fuzzed by the fact that chances are you are tightening it into a thread washed with the oil, and Ford is not explicit about it in the spec. So you may (or may not) depending on the interpretation, further reduce the recommended torque.

The Ford spec (attached) mentioned 21 ft-lb (28 Nm). I did some tests with wrench which goes up to 25 Nm. Going for it from the get go I felt uncomfortable about how deep I screw it without even reaching the torque. So I unscrew it a bit and then set the wrench for 22 Nm, testing how far that torque would get me. Then after reaching 22 Nm and only readjusting the wrench for 25 Nm. I realized I could not move the plug more even with the higher torque set.

Since I did not find the recommended sealant TA-24-B (WSK-M2G350-A2) I put some blue loctite on the plug just to be safe. Even with "undertorqueing" I ended up with about half the thread visible compared to the drain plug, which is still in factory position with the original red sealant on it.

 

[TRDFurgesson]

I'd be curious to know if anyone's came low from the factory.

Not my 2022 Mach 1. Very small amount from the fill hole when removed. Drained, refilled, ran in first gear for 2 min. At idle (Mach 1). I was able to add more after operating the transmission. After topping off a second time, done. I will say the orig. fluid looked terrible (brown) after 8k miles and several track days.

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