Transmission Question -you may have just solved my problem!

[richard waters]

Gary,
I was wondering why my new "Custom Instrument Panels" transmission temp gage was
reading so low. The gage goes from 150-300 and most of the time it never gets off
the peg. Sometimes it will go up to 170 degrees after driving up a grade. Your
informative post made me think about the way I installed the sensor. The sensor is
installed in the transmission case (I removed a plug from the case and installed the
sensor according to the instructions that came with the panel). In my ignorance I
am sure I installed the sensor with teflon tape. What was I thinking of at the
time? Could that be the source of my low readings? I bet if I remove the sensor
and clean the threads and then install as you suggest, "Do not put any thread
sealers on the sensor when you install it -- it must make a good electrical ground
contact", I 'll start to get accurate readings. Thanks for the advice!

This is another example of how one thing leads to another. Keep it up GMCnet! I am
sure learning a lot here and am looking forward to being able to contribute
information rather then just receive it.
Richard Waters, 1976 PB, Troy, MI
- -------------

> "Do not put any thread sealers on the sensor when you install it -- it must make a
> good electrical ground contact. My transmission runs about 170 degrees on
> straight easy roads, climbs to 200 on grades. Get a gauge what goes from 150 to
> 300."
>

 

[richard waters]

Again the power of the internet! I just sent the message and a few minutes later another "tip". So maybe my low readings are normal then?

The readings from my other gages seem normal (water temp, engine oil temp and oil pressure) and their sensors were installed with teflon tape.
Richard Waters '76 PB, Troy, MI
- ----------

> Richard,
> The problem you may be having is that the guage doesn't start soon enough.
>
> If my rig is any indication (I hope the correct one) your temp in the tranny pan is less than 150 much of the time. I'll check my log later to confirm, but I know for sure that in normal driving the temp is less than 150 in the pan most of the time, even towing.
>
> Unless you put LOTS of teflon on, it'll bite through and make a connection ok. (usually
>
> Heinz
>
> -

 

[thomas g. warner]

If you are getting readings than the gauge is working properly. the threads
on the sensor bite thru the teflon tape if you put the correct number of
turns on it.Take an ohmeter and tough the case of the sensor and ground and see.

The problem you may be having is reading the temperature at the wrong place.
You need to read the temperature when it just comes out of the tranny and
before it goes to the cooler. On the hardest pulls you need to keep the temp
below 200 degrees F.



>Gary,
>I was wondering why my new "Custom Instrument Panels" transmission temp
gage was
>reading so low. The gage goes from 150-300 and most of the time it never
gets off
>the peg. Sometimes it will go up to 170 degrees after driving up a grade.
Your
>informative post made me think about the way I installed the sensor. The
sensor is
>installed in the transmission case (I removed a plug from the case and
installed the
>sensor according to the instructions that came with the panel). In my
ignorance I
>am sure I installed the sensor with teflon tape. What was I thinking of at the
>time? Could that be the source of my low readings? I bet if I remove the
sensor
>and clean the threads and then install as you suggest, "Do not put any thread
>sealers on the sensor when you install it -- it must make a good electrical
ground
>contact", I 'll start to get accurate readings. Thanks for the advice!
>
>This is another example of how one thing leads to another. Keep it up
GMCnet! I am
>sure learning a lot here and am looking forward to being able to contribute
>information rather then just receive it.
>Richard Waters, 1976 PB, Troy, MI
>-------------
>

>
>> "Do not put any thread sealers on the sensor when you install it -- it
must make a
>> good electrical ground contact. My transmission runs about 170 degrees on
>> straight easy roads, climbs to 200 on grades. Get a gauge what goes from
150 to
>> 300."
>>
>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach

 

[john dolan]

Richard...

>I was wondering why my new "Custom Instrument Panels" transmission temp
>gage was reading so low.

Tell us a little about your new panel... which one did you get... color..
how long to install it? How does it look?

- --
John, 74 Glacier

 

[david l greenberg]

>I was wondering why my new "Custom Instrument Panels" transmission
>temp gage was
>reading so low. The gage goes from 150-300 and most of the time it
>never gets off
>the peg. Sometimes it will go up to 170 degrees after driving up a
>grade.

Snip................

Keep in mind the oil in the pan will generally be cooler than the oil
exiting the torque converter by about 50 degrees. 130-140 in the pan
under normal level highway driving is not unusual. 180-190 out of the
T.C. seems to be normal.

With a 150 gauge it is likely the pin will stay pegged, eh?

David Lee Greenberg F22009
GMC Motorhome Registry
200 MacFarlane Drive PH4
Delray Beach, FL 33483-6829

 

[thomas g. warner]

But if he is reading 170 on his gauge he is actually exceeding the safe
limit of transmission fluid in the tranny of 200 degrees F (170 +50 = 220).
Maybe this is why GMCs go through so many trannys?

>
>>I was wondering why my new "Custom Instrument Panels" transmission
>>temp gage was
>>reading so low. The gage goes from 150-300 and most of the time it
>>never gets off
>>the peg. Sometimes it will go up to 170 degrees after driving up a
>>grade.
>
>Snip................
>
>
>Keep in mind the oil in the pan will generally be cooler than the oil
>exiting the torque converter by about 50 degrees. 130-140 in the pan
>under normal level highway driving is not unusual. 180-190 out of the
>T.C. seems to be normal.
>
>With a 150 gauge it is likely the pin will stay pegged, eh?
>
>David Lee Greenberg F22009
> GMC Motorhome Registry
> 200 MacFarlane Drive PH4
> Delray Beach, FL 33483-6829
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach