Thread: Transmission temp guage.....

assuming you mean for an auto the easy way is to put it into the filler plug on a later model ZF/GM and on the early ones to do it at your next service and then braze a pipe fitting onto the sump pan (I advocate getting a spare pan first JIC).

The alternate methods are fitting a T piece into the cooler pipe BUT as they have to be replaced if it springs a leak at the flex line you have to remod it.

you can also fit it to the cooler but if you get the wrong side of the cooler you will be reading the cooled temp of the oil which means your atuo box temp is higher than your reading.

the last method is to braze a tab onto the pan and fit a temp sender like the one that just connects onto a bolt but these are known to produce different readings depending on ambient conditions and can be slow to react due to the delay of the heat transfer into the tab and the sender.

I recently fitted one to the D1 when I changed the oil and filter on the ZF. I was going to use the Blknight method and braze a fitting into the pan, but it was then I remembered about the OE temp sensor in the cooler line and just got an M10 1.5(I think) to 1/8 BSP adapter to install the new sensor that came with the gauge into that spot. I figured if the original pickup for trans temp used this, it should be OK for the gauge. I was surprised just how quick the oil heats up on slow big climbs and as the oil momentarily hit the peak 230F max temp towing up timbertop with a HEAVY camper I suspect the original sender wasn't working. As last year I smelt auto fluid in the cab but the light on the dash never came on. Since seeing how the fluid heats up, I have changed my driving habits as I used to leave the auto in D and let it do all the work, I now see how it will just abuse the box and oil. Slippage equals heat and lots of it.

Now that you know how hot they can get, time to get a bigger trans oil cooler.
.5 cents