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Annie Sam posted on March 01, 2010 22:58 
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| The finned exterior of the PWL Titan oil pan give it more surface area to help disperse heat. It also gives the pan more strength, important if you bottom it out offroading or something bad. The thick pan body reinforces the transmission case and helps prevent leaks in the rail area. |
To hopefully cure our transmission overheating woes, we installed the PLM Titan transmission oil pan. The PLM pan holds 3.5 more quarts than the stock Nissan pan. When draining the oil from the pan, usually only about 4 quarts of the transmissions total capacity of 11.25 quarts will come out. The PLM pan ups this to 14.75 total quarts of fluid so you will need 8 quarts of ATF when you install this pan. We used Amsoil’s synthetic automatic transmission fluid due to its superior high temperature properties. You will also need a replacement OEM pan gasket.
In addition to higher fluid capacity, the PLM transmission oil pan has many features such as baffles to prevent sloshing that also act like heat sinks to conduct heat from the fluid to the finned exterior of the pan, thick wall construction that helps strengthen the transmission case, thick sealing surface for leak free service, a boss for a temperature sender unit and a magnetic drain plug.
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| The baffles inside our PWL pan help prevent fluid slosh away from the pickup and act as heatsinks to help draw heat out of the oil and conduct it to the finned exterior of the pan. |
Since we are servicing our transmission and our differential, we also changed the fluid in our transfer case with 2.125 quarts of Amsoil ATF and changed the front diff fluid of our 4X4 Titan with 2 quarts of 75w/90 Royal Purple gear oil.
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| Our pan in place, hopefully this cures our issues and shuts Mike up! |
Hopefully these simple measures will cure the Titans problems as we are sick of Mike bragging about how good his Tundra is. So far we haven’t had an issue at all but the weather is cold. We will update this story in the summer when we have some long hot tows under our belt with this combo. Stay Tuned!
Sources
PWL
Amsoil
Royal Purple
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Tuesday, March 02, 2010 5:23 AM
Interesting story, I've always liked the Titans but it seemed like the Tundra would always steal their thunder. Hopefully these modifications will help keep those temps down. If you guys ever feel like gettin' real crazy why not tap that rear diff cover and plumb in an oil pump and cooler :)
Tuesday, March 02, 2010 6:58 AM
It sounds like alot of your excessive heat problems are coming from towing in D5 instead of D4. I tow my racecar with an Armada and have noticed similar phenomena in the past. In my experience, towing in D5 is OK as long as the torque converter can stay locked, but when it unlocks and slips, the shearing of the fluid in the torque converter causes the ATF temps to go thru the roof quickly. The extra engine speed in 4th gear is enough to keep the torque converter locked and avoid this problem. I don't have my owner's manual in front of me, but I believe it says to tow in D4 mode. Here is a link to a relevant [although not all encompassing, just what I could find quickly] thread on TitanTalk.com about the topic: http://www.titantalk.com/forums/titan-towing-hauling/38568-towing-d-versus-4th-gear-w-tow-mode.html For $200 it's probably not a bad investment, but I could find a better place for that money on my racecar :-)
Tuesday, March 02, 2010 8:14 AM
$200 isnt bad, not if you have ever been stuck on the side of the road. Nissan messed up on this truck, put stuff not rated for the power and claimed tow capacity on it. These is no way I would tow 9000 lbs with a Titian. I have friends that tired to tow big enclosed trailers and had there rear end glow red hot! Tow mode should take care of transmission scheduling issues like torque converter lock up. Nissan just didn't test this truck enough before releasing it. I am not sure if the torque converter can stay locked when towing, it is just a thin band of cardboard like friction material, it would probably burn up easily. Usually tow mode unlocks the toque converter.
Tuesday, March 02, 2010 9:38 AM
The rear end is definitely a weak point as well as lack of testing, which is suprising because that is my job at a competing automaker. We regularly test fully loaded on the same grades mentioned in the article. Sounds like we are doing a good job using customer oriented courses... The Armada was released a year after the Titan I think? And with the IRS I have never had an issue and have heard many tales of people towing tall motorhomes at max capacity in the summer over Grapevine. I disagree on torque converter control though. From what I've read, Tow Mode just changes the 1->2 and 2->3 shift mapping. During flat road towing, there really isn't much load so lockup is feasible if not feedback control with small amounts of slip. But if you're talking about climbing grades, then yes, it will slip the t/c significantly creating lots of heat that the extra engine speed and thus transmission oil pump speed allow more flow for better cooling in 4th gear rather than 5th.
Tuesday, March 02, 2010 9:55 AM
I know on our F250 tow mode unlocks the converter, you can feel it. The Armada uses the Nissan R230 diff which is stronger than rocks. The Titian uses the Dana 44 which is underrated for this app. I think this is the same diff in the old F Body Camaros. The odd thing is that Nissan Tests on the Baker Grade and the Grapevine. They were testing with a big heavy toy box, yet I know racers that experience the glowing rear ends, overheating trannies and warping brakes, in fact every person i know that tows with a Titan usually experiences two out of three of these and some experiance all three. Later Titan's have bigger brakes and the finned alloy rear diff cover which helps alot. It took Nissan years to fix these issues correctly. I think the trannies still overheat. The Titan was a ground breaking truck but Nissan didn't attack its problems aggressively enough and perhaps released early without enough testing.
Tuesday, March 02, 2010 10:16 PM
thats what feeds the heavy aftermarket for Nissans. They do a great job out of the box, and I am convinced that they under-engineer some components as to give their motorsports department something to work on and cut down on pricing. Kind of a big brother looking out for his younger sibling effect. Imagine if everything that Nissan,Honda, Toyota etc. made was perfect from the get go. That would make them overpriced from the showroom floor and make the aftermarket that much more exclusive, taking the pricing and accessability away from a strong consumer range. Essentially they would become like Mercedes/AMG or BMW/M Division. Wonderful cars and development but not accessible to everyone.
Wednesday, March 03, 2010 1:41 PM
From my experience with diesel Chevys and my CTD Dodge, tow/haul makes for more aggressive converter lockup. Putting my Dodge in "2" with the tow/haul button pushed means it locks up at 30mph instead of 40mph. Same thing I've noticed with Allisons. Either way, the key to managing transmission temperature when towing with an automatic is managing converter lockup. If the converter is unlocked, you're making huge amounts of heat. Either drop down a gear, or get out of the accelerator (or both) until it locks back up. I'd rather crawl up a grade at 45mph than nuke an automatic trans. BTW, to tell if your converter is locked up, just let off the accelerator and get back on it. If the rpms follow your foot in a linear fashion, the converter is unlocked. Dick with the gears/accelerator until it locks up. Keep in mind that you can overheat a trans going downhill as well. Mike, I agree, the D44 that comes in the Titans is WAY too small. Previous D44 rear axle applications include such towing beasts as the Izuzu Rodeo, XJ Cherokees and the newer Wranglers. Everyone else only trusts it on the front end. Looking under a Titan, the pumpkin is just laughingly small. I'm pretty sure that F-bodies came with GM's 12 bolt though.
Wednesday, March 03, 2010 2:11 PM
BTW, did you guys look into a larger cooler?
 
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