Welding the tranny temp sender bung into the auto tranny pan

**Jerry Bransford** · 12-01-2007, 04:44 PM

I've decided to mount a tranny temp sender in the pan itself instead of into a T-fitting in the cooler line. My MIG welding skills are only fair so I'm concerned about welding a heavy steel bung to the fairly thin steel 32RH tranny pan (the Mopar deep pan).

Should I just tack it at one point and let it cool, then weld it at widely separated points with cool-down intervals between welds? I'm concerned with getting adequate penetration into the heavier bung without it warping or damaging the thinner pan material. Or am I just overly concerned about this?

**Grape Ape** · 12-01-2007, 05:16 PM

It will be important to keep the heat to the bung. The biggest problem you will run into is burning a hole in the pan. Trying to get the heat to the bung without burning a hole may be a bit tough. If it were me I would do the tack and cool around it, it may take a bit more time but much better than taking a chance of burning a hole in the pan that you have to then fight with to get filled up.

Mr.Crowley · 12-01-2007, 05:39 PM

tack oposing sides while letting it cool inbetween..U dont want to warp the pan..Fill in the voids when theres about an 1/8-3/16 apart..Like said above keep the heat on the bung..I have welded diff covers like this with a cold wet rag under the bung to keep it cooler,but a steady temputure..To pressure test you could get a peice of plexi gass drill bolt patern in it and silicone it on..Get adaptor fittings for air line and put 4lbs of air in it and let it sit..see what it leaks down to after about 10 minutes or spray with soapy water around welds..

**BESRK** · 12-01-2007, 08:44 PM

When I do tranny pans and bungs, I tack weld one right after the other.. tack tack tack. Keep the welder setting at a point where it almost burns through. I hit the next tack just as the puddle from the previous tack "freezes". Warping hasn't been an issue to date. Might practice with a similar gauge of sheetmetal and a large nut or something similar in size to the bung.

One note of caution... make sure to double check the space inside the pan so that the temp sending unit doesn't interfere with the valve body. Also, take a quick look at everything with the pan mocked up to the tranny. Did a sending unit on my T350 pan one time and the "manual" sending unit had the line come out and almost hit the torque converter..

**Jerry Bransford** · 12-01-2007, 10:39 PM

Awesome help guys, I think I'll use the tack-tack-tack method.

One more question, is there any reason I can't flip the new 32RH (TF999) over (upside down) so the pan is on top so I can figure out where to put the bung more easily? I haven't installed the tranny yet, it's still on my garage floor.

**BESRK** · 12-02-2007, 08:32 AM

No problem flipping it as long as it's empty.. that'll keep fluid from pouring all over the floor.

**Matt Gertsch** · 12-02-2007, 10:44 AM

Before you start, take the pan off and wipe the weld area down with lacquer thinner or some other heavy petroleum solvent, it'll prevent weldment contamination. It'll be easier to weld if it is off the trans too.

I'd put a tack at opposite sides from each other ,12 o'clock & 6 o'clock, then let it cool. 3&6, let it cool. 11&5 let it cool. 7&1... No more than 1/4" diameter tack.

Also, point the wire at the bung, about 1/4" up from the pan, then push the puddle down, so it just touches the pan and the puddle flattens out into the pan. The second that the puddle drops like that, release the trigger or you'll blow through. After the first weld, look at the inside of the pan to see if there is discoloration. That discoloration will show that you're penetrating into the sheet metal.

You might want to get some 14 ga scrap and something sized similarly to the bung, like some spare nuts, and run a few mockups to get the hang of it.

Heh heh heh, Jerry said bung.

**Jerry Bransford** · 12-02-2007, 04:04 PM

Matt your last big of advice was exactly what I needed, pointing the wire at the bung and pushing the puddle to flatten out into the pan and then checking for color for adequate penetration. Awesome help, that made sense.

Oh, one last stupid question... weld it from the inside of the pan or on the outside?

Ryanpowell167 · 12-02-2007, 05:22 PM

Both if there is room for a bead on the inside. Double it up will keep it stronger and maybe it will seal up and invisible leak you would have with just one weld.

**leftlanetruckin** · 12-02-2007, 05:27 PM

kind of OT jerry, but when i got the autometer gauges for the heep, i got a tranny temp gauge, and like you, didnt want to do the T fitting deal...
i laid everything out, marked for the bung, and had a local fabricator tig weld a bung in there, cost me a whole $10. $$$ well spent in my limited opinion.
i do have the 220 mig, but just felt a lot better about it being tig'd in there.
also, mine is welded from the outside only...

good luck
martin

**Matt Gertsch** · 12-02-2007, 08:35 PM

I'd weld it from the outside, just to minimize internal clearance issues. If you go slow and let it cool enough, you won't run into warpage. It'll also be easier to get all the way around the bung from the outside of the pan. Just be sure to mock it up after the first tack and see that the sensor will be in the fluid enough to pick up the temperature properly.