Where to put trans oil temp sensor?

[ohecht]

I am looking for a decent way to install a transmission oil temperature sender onto a 915 transmission.

I would prefer to do something fairly easy from the outside that is reversible, like replacing a case bolt, fill or drain bolt, or a magnetic probe or ring mount.

Does anyone know of some good methods fitting this criteria? Tread sizes and pitch for the bolts? Depth available behind the opening, etc.?

Here is a page with some sending unit options.

http://frostalarm.com/cat/p34.html

Thanks,

Olivier

[widebody911]

Perhaps something that replaces (but maintains the functionality of) the vent on top?

[TRE Cup]

We have used the filler plug on the side of the trans case. You can drill and tap the plug for the vdo available sender. That way the hot trans oil splashes up against it while driving. You can't place it in the vent tube up top.

[ohecht]

Through the fill plug sounds like a good idea to get inside without major work or potential damage.

Do you know a good size to use through the fill plug? I think I also need to consider the depth so there is no interference with parts inside the opening.

Thanks again.

Olivier

[Tim Walsh]

For a second I thought you were the one with the transmission cooler but my vote would be through the filler plug. But would that hit anything or get in the way inside?

my $0.02 worth of unexpert opinions

[TRE Cup]

The VDO part number is 323 095. This is a sender that screws into a 1/8" 27 thread NPT (this means pipe thread/tapered) hole.
You can purchase the drill and tap at local hardware store. Check with Pelican re: the sender and matching guage.
This does NOT interfere with internal parts of the trans in any way.

[ohecht]

Thank you, I will look for that part. Once it is installed, I assume you just remove it each time you need to check the fluid so the 19mm allen can fit into the plug?

Olivier

[TRE Cup]

just use a deep socket and leave the sensor attached to the plug. No sense making work twice. The sensor has a slide on connector, so removing the wire is no brainer

[ohecht]

My plug is a recessed 19mm allen, so I don't think that would work.

Is there another type of external hex plug I could use instead to avoid removing the sender to get the fill plug out? Thread size, etc.?

Olivier

[TRE Cup]

some of the 915 equipped cars (72-89 production run on the basic trans) have the external hex plug. Check with some of the shops in your area to see if they have one. We would sell you one, but we like to hoard them for trans pump installs.

[ohecht]

I understand...do you have the thread size and length of the bolt?

[TRE Cup]

24mm x1.5 thread pitch x 17mm long. (Do NOT use the drain plug from the motor /oil tank- that one has a bevel for a seal ring- won't work on the trans)

[ohecht]

Thank you, I will start looking for such a bolt.

Olivier