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safe tranny temps?

Discussion in 'Chevy Trucks' started by highlander316, Aug 16, 2009.

  1. highlander316

    highlander316 Senior Member
    Messages: 578

    on my 07 NBS 2500HD, sometimes when pulling my trailer, the tranny temps get decently high. They'll be around 160 to sometimes even 180 on the hotter days. Is it ok to turn the truck off at these temps? Or should I let the truck sit for a bit to cool the tranny down? If I let it sit, sometimes, it's almost five minutes before it begins to cool down. Would I be better off to put a bigger tranny cooler on?
     
  2. snocrete

    snocrete Banned
    Messages: 2,862

    We run a couple trucks with the same drive.....I asked the dealer about this and was told that those are normal temps, you dont have anything to worry about until you get to around 200 deg.?
     
  3. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    160*-180* is the designed running temp range, so it's working perfectly- don't change a thing.

    If it gets to 210* and continues to climb then you need to take evasive maneuvers and ease up on it.
     
  4. lilweeds

    lilweeds PlowSite.com Addict
    Messages: 1,178

    They tell my it's normal for the Ally's to run a bit warmer, is that correct? They say 210 when towing on a hot day is nothing to worry about at the ally shop.
     
  5. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Allison's will normally run at about twice the ambient outside temp when unloaded plus approx another 20* or so when loaded. 210* is fine and within spec but it depends on the fluid type as to how much "cushion" you'll have after that. The trans itself is happy at 210* day in and day out all day long, its the fluid that makes a difference. If it's filled with Dex III then you want to limit it as much as practical to 210* as a constant running temp. And if you do find yourself exceeding that, then highly consider upgrading to an Allison approved TES-295 series fluid such as Allison's own Transynd or Mobil 1's full synthetic ATF. With either of these two fluids running a constant 240* is no problem and won't shorten the life of the trans or fluids due to heat induced breakdown. It also gives you much more leeway for those extra hot days or those extra big loads before getting into a "too hot" condition. The trans filled with either of these fluids will be happy to run at a much higher running temp than any dino based Dexlll ever could.
     
  6. RichG53

    RichG53 PlowSite.com Addict
    Messages: 1,135

    B&B : What fluid would you recommend for an 01 2500HD Dex111 or ???????
     
  7. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Mobil 1 full synthetic, Amsoil's synthetic ATF, Schaeffer's All Trans ATF or Red Lines synthetic ATF are all great choices Rich. You should have a fluid exchange (didn't say FLUSH) done to purge the old dino fluid out of there in order to get the maximum benefits from it. But it's well worth the small added expense for rewarding you with maximum protection.
     
  8. RichG53

    RichG53 PlowSite.com Addict
    Messages: 1,135

    Thanks !!! What do you mean by fluid exchange ????
     
  9. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    In other words don't allow someone sell you a "flush" for $159.00 (which is a misconseption anyway). Do the job yourself by purging the old fluid out of the cooler return line while simultaneously pouring the new fluid in. A catch can and a few feet of rubber hose is all you need. If the trans hasn't been serviced for a while be sure to also drop the pan and change the filter too.
     
  10. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Ah, confirmation what I've been doing all these years is not crazy. You will see the fluid change color when you get all the old stuff pumped out.
     
  11. Novadiecast

    Novadiecast Senior Member
    Messages: 194

    when you hit 300 and the display says Caution Trans Hot you have over done it. Ask me how I know. It happens very quickly without warning. So watch those guages.