Help Me Decide On Filter Strategy!

[rgiles]

Thanks for all of your inputs. Based upon feedback and research I decided to go with the external oil filter approach using the perma-cool

 

[ALYZ1FLR]

Remote filter delima.

Go with the spin on mounted under bumper and mount temp sender in transmision pressure test port!! HMMM

 

[rgiles]

Re: Remote filter delima.

Originally posted by ALYZ1FLR
Go with the spin on mounted under bumper and mount temp sender in transmision pressure test port!! HMMM

What do you mean by this dilemma, please explain? I was planning on placing the temp sensor on the spin on oil filter mount but if there's a convenient and easy way to get it off the pan, that would be preferrable. Where is this transmission pressure test port?

Thanks

 

[ALYZ1FLR]

Test port

The presure test port is on the drivers side of your trans just above were the shift linkage is. Its hard to see. just feel above the shelf, were the pan mouts. It has a threaded plug in it. This is the port were you check the line presure in your trans.

 

[dogfriend]

There is a port on the side of the transmission case. I don't know exact location, but I could look it up in the manual. The purpose of the port is for testing the line pressure inside the transmission for diagnostic purposes. The line pressure is regulated by the EPC solenoid for the 5R55E.

I would be very wary of using this port for the temp sender. The pressure at this port can be pretty high (> 285 psi, if I remember correctly). I don't know if the typical temp sender is designed or rated for this high of a pressure. (It is a temp sender, not a pressure sender). It may work, but if it fails, the result could be catastrophic.

I think that a better option for the sensor would be in the transmission pan or possibly in the cooler line just as it leaves the transmission. This would give you the hottest temp which is what you want to know. You could add a port to the transmission pan by installing a drain plug (search for trans drain plug). The pressure in the cooler line should be much lower than the line pressure port, so you could tee into the cooler line.

The easiest location is the port built into the aux trans filter unit, but this temp will be lower (another thread says about 15 deg lower) than the high temp.

 

[ALYZ1FLR]

Most gauges that are specifically desighned for transmissions are rated for 500 lbs. Mine was drilled and tapped to 3/4 inch. That port has fluid passing just in front of it coming from the pump. If you want to know what your core temp. is, that is the place to get it.

 

[rgiles]

ALYZ1FLR,

So you are recommending using the pressure port for temperature sensing. Is this what you do? I'm a bit nervous about using that, but puting a tap from the line as it leaves the transmission doesn't sound too bad. I guess I will add it to the remote filter, and then decide over time if I want to move it based upon the results and getting more comfortable with the whole idea.

Thanks

 

[aldive]

Use the port on the filter housing, don't fool with your tranny.

 

[rgiles]

Originally posted by dogfriend

The easiest location is the port built into the aux trans filter unit, but this temp will be lower (another thread says about 15 deg lower) than the high temp.

I think I read this too, but I believe they were talking about after the cooler temperature weren't they? I would be surprised if there is a 15 deg drop in the 6 feet of line from the transmission to the cooler but I can see where the outside temp could play with the numbers significantly.

I plan on tapping in near but before the cooler. The whole pressure port makes me a bit nervous too, although getting a good measurement is important also. That is a dilemma. I don't feel like tapping the pan either, not real confident in tap and dye on such an important component. The inline tap right as the line leaves the tranny might be the best compromise.

 

[dogfriend]

There is another possible option for your transmission. The 5R55E has a transmission fluid temperature (TFT) sensor built in. The signal goes to the PCM and is used to determine shift pressure, timing, etc. I believe that it is attached to the valve body. I believe it is possible to scan for this PID with a scan tool.

If you could figure out how to calibrate the signal, (theoretically) you could use this signal for your trans temp gage.

Re: getting the exact true temp. This is probably not absolutely necessary. If you know that your temp at the aux filter is -15 deg from the "true" temp, then you know the "true" temp. The purpose of monitoring the trans temp is to make sure that you aren't exceeding the fluid capability and turning it into a black, burnt substance. If you are 5 deg off, it won't matter for the purposes of protecting the transmission. If you are 100 deg off, then it would be an issue.

Just my opinion

 

[X24]

Originally posted by aldive
I use the oil filter typr filter and at each change I cut it open to see what it "caught". I have yet to see any particulate matter. But I sleep better knowing its there.

Dead Link Removed

 

[rgiles]

Originally posted by dogfriend
There is another possible option for your transmission. The 5R55E has a transmission fluid temperature (TFT) sensor built in. The signal goes to the PCM and is used to determine shift pressure, timing, etc. I believe that it is attached to the valve body. I believe it is possible to scan for this PID with a scan tool.

If you could figure out how to calibrate the signal, (theoretically) you could use this signal for your trans temp gage.

Re: getting the exact true temp. This is probably not absolutely necessary. If you know that your temp at the aux filter is -15 deg from the "true" temp, then you know the "true" temp. The purpose of monitoring the trans temp is to make sure that you aren't exceeding the fluid capability and turning it into a black, burnt substance. If you are 5 deg off, it won't matter for the purposes of protecting the transmission. If you are 100 deg off, then it would be an issue.

Just my opinion

I know the tranny has the temp guage built in because the service manual specifies using a certain scan tool to monitor the temp to check the fluild level. They specify the "New Generation Start (NGS) Tester". I imagine that the OBDII scanners might start getting this information but for now, I think you need an expensive scanner.

The reason I want close to the real temp is because to check the fluid level according to the service manual, you need to use the NGS to make sure the temp is in the 80-120 deg. F range. That's a pretty wide range so I would guess if I test the level at 100, I should be ok. The temp gauges don't tend to be acurate below 100 so that's the lowest I could test it at. If you assume the internal temp is 15 higher then I'm still within range.

I agree with your opinion that it's just to make sure the temp doesn't exceed the fluid capability.

 

[dogfriend]

I found an RV forum where a couple of guys suggest using the line pressure port: http://www.woodalls.com/forums/index.cfm/fuseaction/thread/CFB/1/Tid/332731/DoOnePage/Yes.cfm

I would still be wary of this however; my manual says the line pressure is 93-123 psi at idle, 228-263 psi WOT Stall in the Forward gears; it is 102-132psi at idle , 282-350psi WOT Stall in Reverse. So if you are going to install a temp sender in the pressure port, don't stand on it in Reverse.

For comparison, the manual says NOT to apply more than 50psi to the cooler lines as a leak check, so I would assume that the pressure in the cooler lines is less than 50psi.

I wasn't able to find any info on the pressure ratings for any of the temp senders that I looked at. Keep in mind that unless the sender uses a separate terminal for ground, they are grounded thru the threads that go into the port. This means you cannot use teflon tape or pipe sealent on the threads because you won't get a good ground connection. This also means that it will be more likely to leak at high pressures.

There is a chart in my manual which gives the resistence of the TFT at various temps, but on second consideration, I wouldn't recommend altering the wiring because you could affect the signal received by the PCM. This could cause more problems than its worth.

I think that there may be other scan tool options that would allow reading the TFT info. I read in another thread that obd2 software can read trans codes Dead Link Removed

 

[Opera House]

Temp sender in transmission

I don't know about newer transmissions but the older A4LD's do not have an internal temperature sensor. There is a trick that could be done to measure the internal temperature. This is the same method I've used to measure internal relay temperatures for my submittals to UL and is very accurate. The transmissions have internal electrical solenoids wound with copper wire. If the resistance of the coil is taken at ambient temperature and then the resistance is measured at operaing temperature, the temperature can be calculated from the percentage change in resistance. Of course you can not do this when power is applied to the coil. This would be easy for a diagnostic tester that plugs into the transmission.

 

[rgiles]

Success! I have just finished installing the Daktota Digital gauge and it all works as expected. I think I'll start a new thread on the gauge installation because it was a totally customized job.

Gave it a road test and my temperature got as high as 187 F but liked to be in the 150-160 range on the freeway with the outside temperature at around 65 degrees.

Oh yeah, I'm getting the temp sensor on the cooler line leading to the radiator. I tapped in at the perma-cool external filter.

EDIT: Here's the new thread Dead Link Removed