2012 GMC 1500 trans hitting 250 towing Jeep up mountain pass

[401 YJ]

I'm not going to say the motor got hot. It was at the hash mark between the 210 and 260. The motor wasn't as big of a concern as the tranny. Power wasn't really an issue either. I wasn't setting any land speed records. I do think that was also part of the problem. You can't go too fast anyway due to the curves on those mount passes.

 

I think I am going to try to run a second cooler in line with the stock cooler. Some guys around here are running tranny coolers that basically look like a large cylinder with fins on it on Jeeps. It should hold an extra quart of fluid. Unless someone thinks this will hurt more then help. How much fluid can you move before the pump is working too hard in the tranny? I have read that 270 is where the warning lights come on but at 250 you could really smell the tranny standing next to the truck. Not a good feeling when it only has 3000 miles on it. I felt guilty for abusing it.

[Jsdirt]

The pump is only going to move what it can move - adding capacity won't change that. By doing that I believe you help the fluid last longer, & make the tranny run cooler - a win-win in my book.

[aflesch]

The pump is only going to move what it can move - adding capacity won't change that. By doing that I believe you help the fluid last longer, & make the tranny run cooler - a win-win in my book.

 

 

+1 The amount of fluid the tranny pumps is directly related to RPM. Period. Adding more fluid will only add more cooling capacity. I design hydraulic systems for a living (a tranny is just that) and the fluid capacity / flow rate = retention time (the time it takes the pump to circulate all of the fluid in the resevoir (pan). This is directly related to cooling capacity. The longer the retention time the cooler the system will operate. So, adding more fluid = longer retention time = cooler running.

 

 

Edit: Adding more fluid by simply overfilling the pan can cause catastrauphic failure of the transmission.

[CKNSLS]

There are a few placed that sell deeper pans (adds about a quart) that also have drain plugs for easier maintenance. I have hit 235 on several occasions towing my 5,000 pound 28 foot travel trailer.

 

My truck is a 2011 Crew Cab-2WD with the 5.3.

 

PM me if you wish and I will send you a link.

[demech23]

For a deep trans pan...

http://www.yourcover...nspan_11025.php

 

For a finned rear diff pan with drain plug...

http://www.yourcovers.com/diffcover_gm85.php