Ok, thanks for the advice. I'll try to find someplace that will hold
it in place with some heatsink goop. The actual measurement value is
not so important as is a relative reading that its either like it
normally is or something that is different. I've already used it
like this to check the tranny fluid temperature on my suburban. I
think I found out that the radiator usually warms up the tranny fluid.

I don't have a pressure gauge. Does the pressure gauge sending unit
simply connect to the telltale spout on the water jacket and elininate
the telltale?

tks
Don WA5NGP