Adding transmisison temp gauge

Thanks B-300.

I wonder which temp is better to watch... the pan or the outlet. Outlet is STILL a transmission temp.. it's the PEAK temp the transmission is getting. If I put it in the pan, it won't be a true PEAK temp for the fluid... and I think that could, in theory, be what's mort important. That hot fluid heading to the cooler is touching parts of the inside of the transmission after all. The pan is actually going to be partly cooled fluid that hasn't yet been sucked up into the transmission, heated up and pumped out.

Wherever you install it, normal driving on flat roads would give you a reference point.

Originally Posted by Cubey

what's mort important. That hot fluid heading to the cooler

Yes, this is a more telling temperature as to if the tranny is overheating. The pan fluid temperature is just telling you that you have a good working cooler.

Thanks. I will be installing on the pressure line then.

Now to decide which gauge to get...

Hey, thanks for the link to the aftermarket deep A-500 pan. Wish I could justify the expense.

Here is one chart indicating the life of the fluid given varied temperatures measured in the pan.



Not sure of the accuracy or if it takes Synthetic fluid's supposed greater resistance to heat into account. Don't know if you are running synthetic anyway in a 727. I gotta run ATF+4, which is at least group III synthetic.

I don't know enough about transmission plumbing but I suspect the cooler output line would be a lot hotter than the fluid in the pan, so perhaps a sender mounted in the output line might unnecessarily cause alarm at first?

I'd guess the Pan temperature sender would report much steadier temperatures than one in the output line. I think I'd prefer the greater range likely to be seen on the output line than an averaged pan temperature.

I wonder if the pan temperature more closely relates to the return line than it does to max fluid temp.

It would be nice if the brass fixtures existed so you could hook a sender inline right at the transmission itself on the output cooler line, rather than at the rubber lines up front.

I bet they do. It might very well be normal brass or iron pipe threads. I'm betting the radiator end of the lines are probably the same as the transmission ends thread wise. Only way to know would be to unhook it and try a nut that fits the radiator's cooler threads on the tranny. I'm gonna just do it up front.... easier to keep an eye on for leaks for one thing, since it already has a rubber hose setup with the big aftermarket transmission cooler.