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Discussion Starter #1 (Edited)
This isn't a complete writeup, but only supplimentary info via pictures.

Drilling a 1/2" hole in your one and only pan is fun.
OutsideHole.jpg
InsideHole.jpg

How the parts look uninstalled.
PlugOrder.jpg

Inside and outside finger tight. The sending unit will fit where the plug would normally go.
InsideInstall.jpg
OutterPlug.jpg

Inside torqued. The washer squishes. The outer view shows the sending unit installed.
Squished.jpg
SendingInstalled.jpg

Here's a view of the pan/plug/sending unit installed. Over night there was one drip on the ground. I wiped the pan dry and it has stayed dry.
This may be because I ran the engine and heating things up helped the seal. I'll see how it goes over time, but I'm confident.
PanInstalled.jpg

Here's how I protected the wire going to the sending unit. the grommet worked out pretty good.
SenderSnake.jpg
Sendreout.jpg
Oil Clean.jpg
 

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Perfect!, nothing like pictures. Did that adaptor come with the sensor or separate? if so can you provide a part #. As mentioned before, the OEM pans are cheap($17.00) to replace if it leaks or damaged. Mine was rusting so I bought a new one and will be drilling it too.
 

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Nice, are you using a different gage in the cab?
 

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Discussion Starter #4
Thanks. It's all B&M stuff. I'm off to the desert and will write how it worked. The pan is dry of oil so that's a plus.

The part number for the gauge and sending unit is 80212. I tossed the plug packaging already. There's another post on the board with a picture of the plug. Just match them when you buy them.
 

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Discussion Starter #5
Update...At daily driving the gauge hangs around a 100. On a warm day it hits 130. On a hot trail under constant stress it hangs around 160. I'm thinking that my installation has a particular electrical resistance that registers lower temperatures. I noticed that I could go with a different gauge that begins registering at lower temps, but as long as I see it when it climbs I'm happy. It drove me crazy at first because it seemed that my installation was goofed up some how.

Maybe someone could explain my gauge/resistance thing better than I, so the next guy could be dialed in better.

I do have a cooler.
 

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Funny you should say that. When I saw the pics, I thought to myself, "That's not a good method for a one-wire sender"... The sender (especially if sealed with teflon tape) probably has resistance to the bung. The bolted-in bung probably has resistance to the pan, which has resistance to the case, which has resistance to the engine, etc.

A better method would be to MIG a sender port into the pan and then install a 2-wire sender or at least seal with loctite instead, then verify less than .25 ohms resistance to the battery with the installed sensor shell to the battery ground post.

Bolt-in fittings are often leaky (copper washers are far better than those squishy teflon ones, too) and be sure to remove all paint from the inside and outside of the pan at the new hole for good electrical contact.
 

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Discussion Starter #7
Thanks DoctorD. I'll work on that. A sender port was my preference, but the transmission shop resisted welding in a port like it was foreign to them and approved of my plan. It's a good shop...I guess not for welding a port. Is this a welding specialty?
 

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No, not at all. It's a BIT tricky since you're welding thick to thin, but I do SEVERAL. I do fleet work, and see many trucks with automatic transmissions. I often punch a hole in the pan the first time, then weld a drain bung for subsequent maintenance. The Rubi pan is easy, since it's only painted. The galvanized pans take a bit more prep. .023 MIG and a few minutes time is all it takes.
 

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Dr. D I'm not too familiar with welding on a thin pan, will the pan distort with mig or would it be better to have it brazed on? I would like to add one to my pan but fear it leaking with the nylon washer type.
 

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Discussion Starter #10
And as you answer his....There seems to be a hundred sending units.

Can you suggest one that is a two wire type? Many have snapping connectors and such.
 

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rubicon joe said:
Dr. D I'm not too familiar with welding on a thin pan, will the pan distort with mig or would it be better to have it brazed on? I would like to add one to my pan but fear it leaking with the nylon washer type.
They're thin and even if they distort, they will still go back on and not leak. Brazing adds MUCH more heat than a quick weld. Don't braze it.
 

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Norminator said:
And as you answer his....There seems to be a hundred sending units.

Can you suggest one that is a two wire type? Many have snapping connectors and such.
I can probably come up with a 2 wire sender if we know the industry part number for the original, or have the ohmic values for the one in there now. Most of these gauges are 60 ohm or 90 ohm (some use 120 ohm) and the senders USUALLY drop in resistance as they rise in temp. In other words: If the gauge reads nothing at 60 ohms and pegged at 0 ohms, or reads nothing at 90 ohms and pegged at 0 ohms, or vice versa...

Once we establish that, the rest is thread size and connector style.

The one wire sender WILL do fine as long as it's understood that the sender MUST have a good ground path without ANY added resistance. even one ohm will knock the readings off. If you installed the sender in a tee fitting inline with the cooler hoses, for example, and used rubber hose to splice the cooler line connections, the gauge won't work at all.
 

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Discussion Starter #13
When I get around to it, I'll work on the grounding a bit and see what happens. I know I could do a better job at putting bare metal between parts.

Appreciate your input.
 

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Norminator said:
When I get around to it, I'll work on the grounding a bit and see what happens. I know I could do a better job at putting bare metal between parts.

Appreciate your input.
An easy test would be to vise-grip a bare-ended wire to the hex base part of the sender that you installed, and touching the other end of this wire to battery negative while watching the gauge needle, (key on). If the needle moves at ALL, your ground path needs help.

Alternately: You could do the same with a digital voltmeter, positive lead to the sender's shell, negative lead to the battery negative stud, scale set to DC volts. ANY reading above 0.05VDC means you need to fix the grounds.
 

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Discussion Starter #16 (Edited)
Update on the original install...

I finally got around to checking the grounding of the sending unit and came up with a solution. Now my gauge acts as expected, registering 180-190 on the streets. I'm assuming that's accurate because I think I heard on this forum that the transmission temps follow closely the engine temps, and I do have a second transmission cooler.
Edit - Since the update, I've done some mountain driving. The temp held at 210 at the highest. The gauge and new grounding position continue to prove themselves.
Edit #2 - I've rerouted my auxiliary cooler and I have better temps now. viewtopic.php?f=23&t=79524


I really didn't understand how sending units are powered and grounded until I mentally chewed on DoctorD's (great help, thank you) suggestion to check the grounding by running a wire from the sending unit base, back to negative on the battery. It also helped to look at the sending unit I broke (tightened the post too much) and figure out how it worked.

The solution was to ground the base better and I wasn't sure how I was going to get a solid metal to metal connection that was secure and durable. I then came up with the idea of putting an eyelet on the ground wire that fit the sending unit. The sending unit acts as a bolt, holding the ground wire to the base.

The oil residue is from the engine. The bolt-on drain is working well and not leaking at all. Ignore the previous snipped ground wire attached to the pan bolt.
 

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Discussion Starter #17
I know this is an old post, but I just want to brag :) My bolt on drain plug hasn't leaked in three years :elf:
 

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I know this is an old post, but I just want to brag :) My bolt on drain plug hasn't leaked in three years :elf:
You're extremely fortunate. I added an aftermarket drain plug to my wife's WJ tranny pan. It leaked from moment 1! Tried another style......no joy. My Rubi's started leaking recently, after three years. I ended up solving both leaking pans by yanking them and taking them to a shop to have the holes welded closed or solid.
 

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Discussion Starter #19
You're extremely fortunate. I added an aftermarket drain plug to my wife's WJ tranny pan. It leaked from moment 1! Tried another style......no joy. My Rubi's started leaking recently, after three years. I ended up solving both leaking pans by yanking them and taking them to a shop to have the holes welded closed or solid.
I hear you. Leak or no leak, I do think welding it in is the preferred way. It's common sense.
 
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