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What did you do with your GMT400 today...or yesterday....

Cant find any dripping from the return line, but it looks like oil is seeping from around the entire timing cover... im about to take this thing back to the shop that did the work and raise all holy hell...
 
Engine degreaser and a power wash. Get it all cleaned spiffy, drive it for a bit and let it sit and then the leak source becomes easy to trace. If they didn't Ultra Black the timing cover, block and WP backing plate mating surfaces (either with or w/o gaskets) before assembly, leakage of any amount is just about guaranteed.
 
Used the truck to pull my 7500 lb camp trailer approximately 400 miles round trip to and from elk camp. It didn't break any land speed records, but made it there and back. The Sisters on I-80 east of Evanston were a crawl, but I expected that not wanting to push things to failure again.

Coolant temperatures were much more under control than the last trip, but still need help. Once EGT got up in the 900 degree range, coolant temp started rising. I'm thinking a new aluminum radiator is in order to replace the used one I put in, I will just have to add the heater core return and steam vent ports to make it work with the stock cooling circuits.

Transmission temperatures were another story. Everything was fine while we were moving and air was getting to the cooler. Once things slowed down after getting off of I-80 and climbing in to the mountains, temps started rising. Judging by heat issues and the awful shudder when moving off-idle, the torque converter is toast. I ordered a Quadstar billet unit today to replace it, hopefully that helps. Next will be a cooler with integrated fan to help get temps down.
 
Will L. said:
If you are seeing the egt cause the ect rise- an inner cooler ought to catch your eye...
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I put a 2nd Gen Cummins CAC in the cooling stack earlier this year. IAT was never above 110 degrees under max boost, approx 16 psi. All of that heat removed from the pressurized intake charge is now going in to the radiator though, which probably isn't helping the issue.
 
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If the torque converter is toast it would be a good idea to put in a new transmission cooler when you put in the new converter
 
I upgraded the transmission cooler to a larger one when I did the CAC install because I'm using the Cummins radiator with it and got rid of the secondary cooler in the stock radiator.
 

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@Chewy1576 , if you want to add a pusher or puller fan to your current transmission cooler, dependent on your mounting configuration, I suggest you check out www.surpluscenter.com for a very good selection of General Cab 12V cooling fans, or if you want to go with higher BTU shedding and a fan, their AKG DCS Series of Oil Coolers with an integral DC fan might be what you're looking for. It's all brand new stuff and a lot cheaper than the performance aftermarket.
 
Chewy1576 said:
Roughly 70 degrees ambient.
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Huh. I wouldn’t have expected much heat trouble at that temp, especially with those low IATs. The converter certainly isn’t helping, but then again that isn’t running through the radiator....though it is still in the cooling stack.
 
n8in8or said:
Huh. I wouldn’t have expected much heat trouble at that temp, especially with those low IATs. The converter certainly isn’t helping, but then again that isn’t running through the radiator....though it is still in the cooling stack.
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It is a used Cummins radiator, it could not be fully flowing or gummed up somewhere. I didn't want to put holes and new ports in a new radiator until I knew it would work, so I started with this one. I'm considering going back to an aluminum GM radiator and modifying the intercooler or going with a big aluminum Cummins radiator and having bugs welded in the end tank for the ports to make it work.
 
@Chewy1576 If it were me, I'd pull that transmission cooler out of the stack, slap the biggest CFM fan that fits on it (and possibly get a larger cooler with a higher BTU shedding capability and/or have Chris coat one up for you) and find someplace you can mount it horizontally (parallel to the floor/road) out of the engine compartment and perhaps next to a frame rail for some protection. The fan (thermostatic switch controlled) will provide plenty of airflow through the cooler.

Pulling that large tranny cooler out of the stack does two things: 1) It increases airflow through the A/C, the CAC and radiator core and 2) It removes a source of heat that's being shed into the above mentioned components
 
Husker6.5 said:
@Chewy1576 If it were me, I'd pull that transmission cooler out of the stack, slap the biggest CFM fan that fits on it (and possibly get a larger cooler with a higher BTU shedding capability and/or have Chris coat one up for you) and find someplace you can mount it horizontally (parallel to the floor/road) out of the engine compartment and perhaps next to a frame rail for some protection. The fan (thermostatic switch controlled) will provide plenty of airflow through the cooler.

Pulling that large tranny cooler out of the stack does two things: 1) It increases airflow through the A/C, the CAC and radiator core and 2) It removes a source of heat that's being shed into the above mentioned components
Click to expand...

Next step with the transmission cooler for sure is adding a fan. If it won't fit where it is behind the grill, I'll look at relocating it. The CAC is sitting where the AC condenser was, so I have that going for me.
 
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