Igotr8e8rs

Hot auto transmission

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I'm draining the trans pan on my Silverado. I noticed how close the exhaust pipe is to the pan. Ive seen trans temp as hi as 280 on a warm day towing a fully loaded toy hauler. That temp is/was only for short periods like going up a hill. I was told not to worry about it if it's for short periods and if it stays under 300. And change the fluid regularly. Which I do. It's 35k miles since I last changed the fluid and filter. So, in regards to the ex. pipe I wonder if I put a heat sheild of some sort between the pan and pipe if it would help at all.

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When you're driving down the road and air is flowing over the pipes at 70 mph, it's not transferring much heat to the oil pan.

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You're right. But, I'm more concerned when I'm doing 30 or 40 up a hill with the pedal to the metal. The exhaust pipe is getting hotter and hotter, and the trans is getting hotter and hotter and it seems it would perpetuate the heat.

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the exhaust is not the source of the problem, the load is. Allison or the 4L60E or 4L80E? Would highly recommend Transsynd synthetic fluid over all others. Also a THOROUGH cleaning of the radiator fins with water flushed from back to front to get rid of debris/dirt build up. I did this with a 2004 duramax, and it made significant changes to operating temps under load as well as unloaded. If you are diesel, keep EGT's under 1100

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I wasn't saying that there was a "problem.  I'm just wondering if I could maybe lower the temps a bit by covering the ex pipe. 

I'm gonna look into the synthectic fluid. The radiator is clean. Trans is the 6L80E

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I mean, it is going to hurt anything?  Probably not, but I suspect you'd be much better off spending the money on a larger transmission cooler and good fluid.  Just my personal opinion.  Those are some pretty high temps.. hotter than I'd let mine get for sure (same transmission)

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After you pull the pan and change the fluid, you can put a hose on one of the trans lines at the radiator and pump the old fluid out two quarts at a time.  I over fill by one quart, start the engine, pump two quarts out, and repeat until fluid looks clean.  

For convenience, buy a pan with a drain plug, if you’re changing fluid often.  

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Replace GM's little tiny trans cooler with a real one. If I remember correctly the coolers they used on the 4L80 and 6L80 are around 9,000 btu. An upgrade to a 24,000 will run around $100. If you're pulling extreme hills at 1st gear slow speed then a fan forced unit isn't a bad idea. GM must know this, I think the cooler on the old P30 chassis with the 4L80  was around 40,000 btu.

GM has always used undersized coolers on their gas vehicles. It's the very first thing I've done on every Suburban or Silverado I've ever owned. Heat wrapping the exhaust pipe isn't going to do much of anything. 

If you live in an area in CA that gets real cold then you'll likely want to install an inline thermostat control to your trans cooler. My 8100 Suburban doesn't have one because it rarely gets cold in Arizona but I've seen the temp needle stay on the low peg in Colorado in extremely cold weather even towing with the large cooler (35,000 btu). That's probably not really the best thing in the world for the trans, especially if you're not running synthetic oil. 

The 4L80/5 and 6L80/90 are tough trans. Keep them cool and they'll outlast the truck. :thumbsup: 

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12 hours ago, Baja Rambler said:

After you pull the pan and change the fluid, you can put a hose on one of the trans lines at the radiator and pump the old fluid out two quarts at a time.  I over fill by one quart, start the engine, pump two quarts out, and repeat until fluid looks clean.  

For convenience, buy a pan with a drain plug, if you’re changing fluid often.  

I've already put  drain plug on the pan as I've done with several vehicles over the years

4 minutes ago, Ud_Luz said:

Replace GM's little tiny trans cooler with a real one. If I remember correctly the coolers they used on the 4L80 and 6L80 are around 9,000 btu. An upgrade to a 24,000 will run around $100. If you're pulling extreme hills at 1st gear slow speed then a fan forced unit isn't a bad idea. GM must know this, I think the cooler on the old P30 chassis with the 4L80  was around 40,000 btu.

GM has always used undersized coolers on their gas vehicles. It's the very first thing I've done on every Suburban or Silverado I've ever owned. Heat wrapping the exhaust pipe isn't going to do much of anything. 

If you live in an area in CA that gets real cold then you'll likely want to install an inline thermostat control to your trans cooler. My 8100 Suburban doesn't have one because it rarely gets cold in Arizona but I've seen the temp needle stay on the low peg in Colorado in extremely cold weather even towing with the large cooler (35,000 btu). That's probably not really the best thing in the world for the trans, especially if you're not running synthetic oil. 

The 4L80/5 and 6L80/90 are tough trans. Keep them cool and they'll outlast the truck. :thumbsup: 

That's good to hear! That's another thing that I've done over the years on quite a few trucks, is an aux trans cooler. But, I haven't on this truck just cuz........idk, cuz it's so modern? :excuseme:  But I will, tho. :thumbsup:

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