Transmission Temp

[bill18163]

I have a 2008 Suburban with a 4.10 rear end. I took my flat bed trailer to get some gravel the other day and I told the guy with the loader to put 2-2.5 tons on it. I had never hauled any gravel before so I had no reference in my head as to the volume that would be approx that weight. When they weighed the load on the scale I had 4.4 tons on the trailer. There was no way to get it back off and the trailer looked OK so I took the load and limped home at 25-45mph. Something made me check the transmission temp so I pulled it up on the display and it hit a peak of 209 on the way home. This was when I was going slow in the city. When I hit the open road and could get up to 45mph the temp went back down to 169 or so. The question I had in my mind at the time was how much temp could the transmission stand without the fluid breaking down? Anyone have any input here?

[Jimmiee]

I have a 2008 Suburban with a 4.10 rear end. I took my flat bed trailer to get some gravel the other day and I told the guy with the loader to put 2-2.5 tons on it. I had never hauled any gravel before so I had no reference in my head as to the volume that would be approx that weight. When they weighed the load on the scale I had 4.4 tons on the trailer. There was no way to get it back off and the trailer looked OK so I took the load and limped home at 25-45mph. Something made me check the transmission temp so I pulled it up on the display and it hit a peak of 209 on the way home. This was when I was going slow in the city. When I hit the open road and could get up to 45mph the temp went back down to 169 or so. The question I had in my mind at the time was how much temp could the transmission stand without the fluid breaking down? Anyone have any input here?

Hi Bill,

It all depends on the type of fluid. Synthetic oil can stand much higher temps than conventional oil. 209 degrees is well below the threshold so you have nothing to worry about. I think 250 is the borderline with non synthetic oil.