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Tranny temp gauge- elec. or mech.?

Discussion in 'Chevy Trucks' started by JohnnyU, Jan 13, 2003.

  1. JohnnyU

    JohnnyU 2000 Club Member
    Messages: 2,040

    I have found many threads recommending the use of a gauge, but none have indicated an advantage of one over the other. Is an electrical gauge better than a mechanical? or vice versa? Or, does it even make a difference which i get. One last question about installation. Which type is easier to install, I would assume the electrical gauge would be, but have never had experience with tranny temp guages.

    Thanks, John
     
  2. wyldman

    wyldman Member
    Messages: 3,265

    A mechanical gauge is easier to install,although it may be harder to plumb,as both the sending unit and tubing is sometimes much larger and all one piece.You only need to connect the electric portion if you want it to light up.

    An electric gauge uses a smaller sender,the wiring is smaller and easier to feed,and you can mount it wherever you want.I have had problems with the wiring corroding off on electric ones due to the location (under the truck),and all the salt.

    We run mechanical gauges in our trucks.Weld a bung into the pan and the gauge tube comes right up threw a hole in the floor.
     
  3. fordman

    fordman Senior Member
    Messages: 327

    I run an electric one. It works fine for me and I have never had a problem with it. It was a little complicated to install however. The part that taps into the tranny in the kit I got was to small. Made for a 1/4 inch tranny line. My truck has 1/2 inch tranny lines. Managed to pick up the right fitting thru my mechanic who works on a lot of bigger trucks.
     
  4. Joey D

    Joey D Senior Member
    Messages: 280

    I would not istall the sensor in the pan. True temp will be in the line going to the cooler as close to the trans as possible.
     
  5. Dave_Dean

    Dave_Dean Junior Member
    Messages: 28

    temp gauge

    I am running an electrical temp gauge from Autometer. They aren't too hard to install. Autometer suggests putting it in the pan but I opted to install it in the cooler line. Napa sells a T fitting that can be spliced into your out bound line going to the cooler. They sell all the fittings needed. If you are really concerned about the temp you can also install another gauge on the return line to see how effective your cooler is working. If you install the sending unit in the cooler lines you will have to run a ground wire from the T fitting to a grounding point. Haven't had any problems with mine as of yet and it'll give you piece of mind.

    If salt and corrosion is a concern mount the sending unit somewhere in the engine compartment out of harms way. This way if need be you can rinse it off when you are rinsing off the rest of the truck.
     
    Last edited: Jan 15, 2003
  6. JohnnyU

    JohnnyU 2000 Club Member
    Messages: 2,040

    I installed the gauge this morning, turned out great, I'll try to post pics when I get them. But I have one other question.

    My truck had an aftermarket cooler in it in addition to the cooler in the radiator when I bought it. I noticed today that the atf goes into the aux cooler first then into the radiator cooler, isnt that backwards? Should I reverse the lines or just leave them alone?
    Thanks for your opinions guys.

    -John
     
  7. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    Ive run both,go with mechanical if you can. They are more reliable,IMO.
     
  8. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    Bowtie, it should go through the radiator cooler first, that will knock down the temp, then pass through the Aux. to knock down the temp some more. At the same time, passing through the radiator first will help warm it up in colder months (though probably not much). If it was my truck, I would replumb the lines correctly. Now that it is installed, you might need some pieces of line and a few fittings to change it around.

    ~Chuck
     
  9. wyldman

    wyldman Member
    Messages: 3,265

    I think it's better off going through the aux cooler FIRST,and then back through the radiator cooler.

    The tranny fluid coming out of the trans can get pretty hot.In the summer months,when the engine,and tranny are working hard,like towing a heavy trailer or load,adding all that heat to the cooling system can overtax it,and make it run hot.Running it through the aux cooler first will pull the temps down,and not add all the extra heat to the cooling system.

    In the winter,a large aux cooler can cool the fluid too much,causing the trans to run too cold.This effects the newer electronic trannies of today much more,as they are designed to operate with the trans oil at the correct temperature (they use a trans temp sender for the PCM),and if it's too cold,they will not operate correctly.Running the oil through the radiator mounted cooler LAST,will add heat to the trans fluid,and keep it at the correct operating temperature,even if it has been overcooled first by the aux cooler.

    I have hooked them up both ways,and for a year round truck,that gets worked hard,going through the aux first,and then back through the rad,seems to provide the best combination,for normal,steady fluid operating temperatures.The only time I would do it different,is if you don't run in cold weather,then you can connect it the other way,or even eliminate the radiator cooler altogether.Like on a race car,or hauler.

    Now that you have you trans temp gauge hooked up,run it the way it is for a bit,and pay close attention to the trans temps and engine temps when working\driving\towing,and then switch it around so the fluid goes through the rad first,and note the differences.Try the same thing in the winter,and again,see which way works better.Post your results,as I know many people are probably going to disagree with my opinion on this one.
     
  10. CARDOCTOR

    CARDOCTOR PlowSite.com Addict
    Messages: 1,310

    only problem with mechanical gauge is you have trans fluid running to the gauge if it spring a leak you lose fluid and its all over the inside of the truck



    cardoctor:gunsfiring:
     
  11. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    Cardoctor, trans fluid will not come in the truck,the most that can happen is a sender failure,the temp bulb seals off the hole,so no issues there.If you have a guage that runs trans oil into the cab,it must be a pressure guage,not a temp guage,and they would be used for oil pressure in 99% of the cases,
     
  12. CARDOCTOR

    CARDOCTOR PlowSite.com Addict
    Messages: 1,310

    DAh
    had a momentary lapse of stupidity

    i knew that. miss read the question
    think my brain was waterlogged



    cardoctor:blush2:
     
  13. JohnnyU

    JohnnyU 2000 Club Member
    Messages: 2,040

    Chris- I shall try that. Since ive not even been able to monitor temp on this truck a have noticed something strange. It seems to be very slow in climbing, is that normal? It will hit 100 around the same time the radiator does, then it slows down, tops out at around 130-150, under normal load (just truck, two passengers, no trailer, just tools in toolbox) Thanks again,

    John
     
  14. Garagekeeper

    Garagekeeper Senior Member
    Messages: 459

    Trans Temp

    Hey John your transmission temp should be much lower then your engine temp. Remember that your reading "cooled" trans fluid thats been thru two coolers, while the engine temp is taken off the engine block or a water jacket on the intake manifold. The other thing is when you reroute your lines on your cooler see if you have room to separate the trans cooler farther away from the a/c condenser, this will allow for more airflow and heat dissipation. I have measured anywhere from 10 to 30 degree trans temperature change during summer usage just by moving them apart.
    Every degree you knock off adds to the life of your trans....
    :rolleyes: John
     
  15. wyldman

    wyldman Member
    Messages: 3,265

    Those temps are pretty normal.If you didn'thave it through the rad as well,it would hardly climb at all until you work it hard.That's why I recommend going through the rad last,so it keep the operating temp up to normal when it's not being worked hard.

    Put a trailer on it,or start pushing it hard,and it should get up there a bit.
     
  16. JCurtis

    JCurtis Banned
    Messages: 862

    My 2000 GMC Sierra has a blank knockout in the dash pod under the message panel . The owners manual shows this as a spot that would hold a transmission temp gauge.

    I would love to try and install it myself, but I was thinking maybe I should get the OEM gauge and have a dealer install.

    Any thoughts?
     
  17. wyldman

    wyldman Member
    Messages: 3,265

    Check with the dealer to see if you can get an OEM unit and just pop it in.It will have to have all the wiring,sensor,etc already in the truck for it to work.The dealer should know if it is possible.

    If it is,it's not hard to pop out the cluster and put it in yourself and save the labour $$$.
     
  18. JohnnyU

    JohnnyU 2000 Club Member
    Messages: 2,040

    Many guys have just bought a cluster from new HD, Most are getting it from Ebay. I am not sure if the Dealer has to reflash the computer or not, Here is a link to a thread that discusses this in a little more detail.

    -John
     
  19. wyldman

    wyldman Member
    Messages: 3,265

    There is no reflash required to do a cluster swap,but the cluster will have to be reprogrammed to get the correct mileage.Everything else will work fine,including the trans temp gauge,but the mileage will read at whatever it was on the donor truck the cluster came out of,or 0 if it is a brand new one.

    You must by law attach a sticker to the door showing the unit has been changed and what the original mileage is.I would highly recommend you reprogram the correct mileage though,as it is stored in other computers,and a discrepancy will result.