Where is the test port on an old (87) C6 ? I'm installing a tranny temp gauge and didn't see the test port. Am I missing it ?

 

No test port on a C6, you have to drill and tap into the pan.

 

Really ?? Are you serious ?!?!?!?! That seriously sucks !!!! I thought I was missing it somewhere, but that presents another problem. Since I haven't planned on pulling the pan, any idea on the best location in the pan? I had planned on only doing a tranny flush, but if I have to pull the pan, I'll just do a complete tranny flush/ filter change and get the bung placed in the pan.

For what it's worth, I pulled the front end down today and found a good spot for the coolant temp gauge sensor right beside the distributor. The stock sensor is located on the intake manifold just on the driver's side of the distributor. There is another port (with a plug in it) located just on the passenger side of the distributor (between the distributor and thermostat housing). I took out the pipe plug an the gauge probe fit perfectly right there. This way, you can leave the stock gauge intact while having the aftermarket gauge also.

 

A pressure test port would do you no good for anything but testing pressure.
The sensor needs to be where the fluid moves and mixes.
A believe a sensor in the supply line to the trans cooler close to the trans would be most accurate.

 

I agree, I was just trying to figure out a decent compromise between best and easy. B&M makes an inline mounting kit usiing a brass "T" with compression fittings. I'm just not sure how the compression fittings will hold up on the steel lines. I guess I could put the compression sleeve on the line and slightly tap the line end to make a very slight flare to help hold it on ??

 

The compression fitting will work just fine. I still think the pan is the best place.

 

i believe compression fittings can work quite well on steel lines. and i would figure B&M tested their product on steel lines before putting it on the market. maybe google their name with words like "failed" or "junk", and see what you find. i haven't looked, but if they're prone to having problems, you'll find plenty of people posting about it, and if they don't have problems, you'll find nothing about them

 

I think the pan would give the best "average" temp. The line coming from the trans will likley give me the hottest readings. Doesn't the line come out right after the fluid exits the torque converter?

If I could fiind a reasonably priced pan with a sensor bung in it, I'd buy it. I just refuse to pay $200 for a pan. Looking at the stock pan, I'm not sure there is enough clearance in there for a sensor. I looks REALLY close. If I knew a place it would defineltly fit, it might be worth it to have one installed, but I'm not looking to screw up my pan if I measure wrong. I'd much rather buy one already installed.

So I figure the line is the next best place.

 

Yes, the supply line to the cooler shows the hottest fluid temp, and the fluid temp indicates the damage done to it and it's life expectancy.

To have the trans fluid (and the seals in contact with it) experience a long life, the trans fluid's maximum temp no matter where it is should be the guide to cooling it.

I have rebuilt transmissions where the hot fluid caused the seals to harden and wear grooves into the aluminum parts they touch.

The major key is that if it is not a closed/sealed system, is to have the fluid be just hot enough to "boil" off any moisture it may accumulate, but no hotter.

 

Does anyone know if anyone makes inline (in cooler lines) temp sensors?


I to want to add a temp gauge to my C6's, but ain't much a fan for drilling pans.... and the finned aluminum ones with the plug for the sensor, are to expensive for no reason.

 

That's kind of what we've been discussing.

B&M makes a kit that includes everything including the inline sensor. This is just a quick link, but Summit and Jegs sell it also. I think I'm going to make a similar kit to use with my Autometer gauge since I can't afford a new pan either.

B&M Transmission Temperature Gauge kit | Northern Auto Parts

 

Gotcha...So what kind of temps would I be looking at if I tapped into the front line ? My Ranger has a temp gauge also (in a test port), and it shows pretty much a constant temp of 190 F during the summer unless I'm towing. If this proves to be better, I'll probably re-plumb my Ranger.

 

A good range for any auto trans is 150-190*, but safely go up to 210-220 under towing conditions, as long as you don't let it stay that hot for ever.



And big thanks for that link! I'm gonna order a few when time comes!

 

I never liked those "clamp the pan between two nuts" types of drain plugs.
There is always a little old fluid and possible trash caught by the internal nut that would get pushed out by the flow if it were flush.

I drill a hole and braze a nut to the bottom corner of the pan.
I also place a doughnut shaped magnet over/around it and remove it before draining so that any metal gets pushed out first thing when draining.

 

When the sensor is in the line to the cooler expect your temperatures to go WAY above that!