What is this bolt/plug on the AW4?

This is Grimm's junk, not mine, but I couldn't find another pic of the side of an AW4.

In the red circle. Doing a drain-n-fill on my junk today, and I noticed this bolt. It's a pretty large Torx bolt, just forward of the outgoing quick disco, right under the dipstick tube. I'm looking to add a trans temp gauge to my junk in the process of replacing/rerouting some cooler lines, and wondering if this bolt is a candidate for replacement with an adapter and sender. Don't know if this is a solid idea, so I thought I'd ask. Thanks.

The parts diagram just says "plug". I think the ball and spring for the shifter detent is under there. I would suggest Teeing into the return line and put the sensor in there. Sensors usually have standard pipe threading anyway.

Aren't those nice new cooler fitting pointing the wrong direction?

nope, theyre pointed to his tranny cooler, which is mounted in the rear.

back on topic, no idea what that is.

Yeah, he has his cooler mounted on the quarter panel/behind the C pillar, IIRC.

I did find a thread where someone said they were going to pull that plug and drop their sender in. The thread size is supposedly M14x1.5, just like the cooler lines, making me think it might actually be a pressure test port. But, they opted to put a tee on the output line instead. Probably the route I would go, but I can't find even find those locally. 3/8 comp (female) to 1/8 NPT (female) is not a common part around here- I can't even find the 4 or 5 pieces I would need to make it work in stock. With AN lines and fittings, this would be stupid simple with no cobbled together fittings needed. Hate living in a small town.

About the best pic I could find- think it's from an FSM, but I can't find any clear reference to it.
http://i266.photobucket.com/albums/ii244/AHhub/forum stuff/aw4bolt.jpg

I want to say it's a pressure test port but I'm not sure. The parts catalog just calls the bolt "PLUG, Transmission Case." I have a pair of scrap AW4s sitting on my back porch though, will be gutting them at some point and I'll let you know where the other end of the hole goes when I do.

Also I'm fairly certain that pic is NOT from a jeep AW4, the dipstick tubes are shown separated. I am pretty sure it's not possible to ever see that on a jeep AW4 :roll:

I would just put the sensor in the pan, or in one of the lines.

If you do confirm what that bolt is, I'd like to know. M15x1.5 to 1/8 npt female adapters are common parts, and that would be a very clean and simple install, if it is a suitable port to read fluid temps.

In the process of digging through a bunch of trans temp gauge install threads on truck forums, I read about Swagelok tube fittings. Supposedly popular with the hot rod crowd for just this sort of thing. They make tees with 3/8 tube and 1/4 NPT male and female threads on the leg (pn B-600-3TTM or -3TTF for brass, SS- for Stainless), which would only require a simple 1/4 to 1/8 adapter, and those are common parts as well. The Swagelok parts cross-ref with 10 other parts from various brands and lines, so such parts do exist, if not specifically for automotive use. B&M gauge kits come with a nearly identical setup. I don't consider that setup ideal, but lots of people use it and don't seem to report a lot of issues. I have never been a fan of compression fittings, but I think the cooler lines see much lower pressure than I've had to worry about in the past- probably overthinking this.

Either way, special order parts and waiting for a week, but better than cobbling together a bunch of plumbing parts and adding that many more potential leaks/inaccurate readings.

kastein said:

I want to say it's a pressure test port but I'm not sure.

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The hydraulic pressure test port is further back. That might be an option.

After more reading, it looks like the test port is actually toward the rear, next to the name plate. Still trying to figure out what that forward plug is. Wondering if that's in the housing for a Toy application.

I'm still amazed/annoyed that I can't walk into a parts store around here and buy a piece of hardware to screw a sender into a line. I hate this town.

It has been brought to my attention that the flow past the test port(s?) makes them poor locations for temp senders. So, that could very well be why no one seems to have done this. In looking at a Supra manual, I see the same bolt depicted in drawings, but is not specifically mentioned there, either. Obviously at least one of them is a test port, but seeing that neither will be useful here, it's kind of a moot point now.

yeah... that is why I will be putting my sensors in the lines. I'd put one in the pan but it seems like a lot of work unless I sneak the wiring in via the same gasket/seal as the solenoid drive wires.

If you can get the pan off, mounting a nut for the sensor to screw into would be the best option

Maybe screw it into the drain plug with an adapter (drain plug is metric I believe)

Putting things that delicate on the bottom of the pan is asking for trouble... I know hubs isn't a rock crawler, but if I put a sensor down there, it would get sheared off quickly.

hubs97xj said:

It has been brought to my attention that the flow past the test port(s?) makes them poor locations for temp senders. So, that could very well be why no one seems to have done this. In looking at a Supra manual, I see the same bolt depicted in drawings, but is not specifically mentioned there, either. Obviously at least one of them is a test port, but seeing that neither will be useful here, it's kind of a moot point now.

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I know a couple people who have used the test port. What is it about the flow there that makes it a bad location?

Gah, long post detailing my reasoning behind and concerns with each approach. Trying to do a couple of things at once, finally hit post, and has logged me out.

I don't wheel, but I do have to drive through brush and unkept lanes, drifted snow in the winter, etc. I don't think the wiring from a sender would last even a year if mounted in the bottom of the pan.

Diesel, I don't really know. This is the first AT I've ever fooled with, having had manual gearboxes almost exclusively since I started driving. I think the fluid at the test ports has only been through the pump, not through the transmission itself, so I wouldn't be reading the "hot" temps. No idea if this is actually the case; I'm pretty clueless here, obviously.

There are different opinions on where to put the sender, how to mount it, which temp readings matter more, etc, and I'm still trying to figure this all out. I've never cared about fluid temps or what was going on, but I'm starting to use the Jeep to do more towing/hauling, and the transmission was pretty neglected for a long time. I've started playing catchup with maintenance, along with adding a cooler, replacing lines, putting a gauge on it, etc, which leads me to this.

Even if it has been through the tranny itself - if it's too far "off the beaten path" i.e. out of the flow of the fluid, it will respond very slowly and will probably read a good amount below actual fluid temp simply because nothing really gets to it. The way I've got mine set up (I have bought the parts and assembled them, but haven't installed it yet) the sensor is screwed into the side of an NPT T-fitting and the "probe tip" (it's a CTS, I plan to set up a toggle switch to feed the stock temp gauge the signal from whatever sensor I want to read at the moment, this will only work 96-) is actually near the center of the fluid path through the other two ports on the fitting.

I'm talking about the side of the pan, not the bottom. What kind of dumbass would even think about the bottom

Also I'd like to see pics of multiple AW4 drain plugs smashed up from rocks

ehall said:

If you can get the pan off, mounting a nut for the sensor to screw into would be the best option

Maybe screw it into the drain plug with an adapter (drain plug is metric I believe)

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ehall said:

I'm talking about the side of the pan, not the bottom. What kind of dumbass would even think about the bottom

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Well, you are the one that suggested the drain plug location. The plug is in the bottom of the pan.

ehall said:

If you can get the pan off, mounting a nut for the sensor to screw into would be the best option

Maybe screw it into the drain plug with an adapter (drain plug is metric I believe)

Click to expand...

ehall said:

I'm talking about the side of the pan, not the bottom. What kind of dumbass would even think about the bottom

Also I'd like to see pics of multiple AW4 drain plugs smashed up from rocks

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the drain plug is on the bottom. I am confused by the fact that you suggest the drain plug, say only a dumbass would think about putting it on the bottom, and then say that drain plugs don't get smashed up from rocks.

I haven't smashed up the drain plug (yet), but I have scraped the pan itself up pretty good.

DieselSJ said:

Well, you are the one that suggested the drain plug location. The plug is in the bottom of the pan.

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:laugh: