Fluid Type

**wdw66** · 08-31-2009, 03:53 PM

I have a 2004 Suburban 2500. I tow a 33 ft Travel Trailer weighing 7000 loaded. Should I follow the suggested maintenance intervals in the manual or service sooner? Are there a heavier duty fluids I should use?

**Z71_guy** · 08-31-2009, 04:05 PM

i would suggest switching to synthetic fluids

**2COR517** · 09-01-2009, 12:02 AM

The advantage of synthetic fluid is that it is much more tolerant of heat, and will not break down as fast.

Your Sub has the 4L80e, like my truck. When I had mine rebuilt last winter about synthetic, they said I would be throwing money away. These trans just don't build as much heat. All the guys at the shop drive Ford pickups. They said Chevy transmissions are the most reliable/durable, and the 4L80e is the best trans in a pickup right now. Dodge transmissions are the worst. I asked about a shift kit and synthetic fluid. They said not to bother. But they said they always put shift kits and synthetic fluid in the Ford trans because they build so much heat.

Having said that, synthetic fluid is probably still cheap insurance, especially if you do it yourself. You should pump out all the fluid though. Do some searching, Jimmiee and I have outlined the procedure recently.

**2COR517** · 09-01-2009, 12:05 AM

Changing trans fluid annually is a good baseline. Depends somewhat on how you use it. A trans temp gauge would be a good idea. That way if you get in a spot and you really get it hot, you'll know to change it right away.

**1st Synthetics** · 09-01-2009, 12:39 AM

I do recommend using AMSOIL sever gear in your rear end. It is the toughest & longest lasting gear oil on the market. You will notice a diffrence in heat displacement along with fuel mileage. Also I would use a good synthetic ATF, this is always a good idea.

As far as drain intervals I would stick to whatever the sever service drain interval is in you manual or what the manufacture of the product recommends for severe service.

**Jimmiee** · 09-01-2009, 07:58 AM

Originally Posted by 2COR517

Changing trans fluid annually is a good baseline. Depends somewhat on how you use it. A trans temp gauge would be a good idea. That way if you get in a spot and you really get it hot, you'll know to change it right away.

Good point about changing the ATF annually. The manufacturer recommendations are way out of whack on most vehicles. The key to making your transmission live is to keep the oil clean. If you change it annually you will never have to worry about flushing as a pan drop and filter change is all that's necessary.

**wdw66** · 09-07-2009, 09:02 AM

Thanks guys, I drive my suburban everyday in normal conditions but tow a 33 ft travel trailer several times each year in varying conditions, most of the time relatively flat or foothills and sometimes in the mountains of GA, NC and TN. I did recently have one hill that the trans temp gauge got up to the red but not into the red. I am planning another mountain trip next month so I'll go ahead get it changed. I want to keep it in as good shape as possible. I've looked at other vehicles but in talking with folks about brands I definatley want to stay with a Chevy or GMC and until I need a deisel my burb is great for the family. Thanks again