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Fresh Rebuild With Temp Problems

Austin Huff
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Austin Huff New Member

Austin Huff

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This may have been covered somewhere before and I’ve spent hours googling it, but I’m having what I think might be temperature troubles with my fresh rebuilt transmission. It’s a 2008 4.8 4x4 with the 4 speed and 3.42. My owners manual says normal operating temp is between 160-200. All summer long, it was nothing for me to hit 215-220 with no load. The shop had it in for a long time to try different things. They said they pulled the trans back apart and everything still looked new and they put another new torque converter in it, just in case. They said they added an additional trans cooler. They said they replaced a pump that pumps the trans fluid through the cooler and replaced the radiator. He eventually said he didn’t know what else to do to make sure everything ran cooler. He did all the work, except the rebuild, for free. That makes me think he was also worried that the temps on the transmission he rebuilt was too high. Now that he did all of that, it will run in the upper 190’s out on the road and go back over 200 (208 is the highest so far) at slow in town speeds and idling. The truck is lifted only 3 inches and has stock size all terrain LT tires, so I wouldn’t think that would cause much extra heat from working harder. I also don’t know if the only reason it’s now running in the 190’s instead of over 200 is because the temperature has dropped from the 90+ degree days down to the low 70’s. I also feel like the trans shouldn’t go over 200 from just sitting there idling. I prefer to drive with my windows down, but I have noticed it’ll stay a bit cooler, or cool down much faster at idle, if I turn the AC on and cause the fans to kick on. I planned to get slightly larger tires and/or maybe a small travel trailer and I’m worried that the temps will stay over 200 all the time with that, especially hot summer days. I don’t know if I should be worried about these temps or not. 

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