Nissan Titan Large Capacity Oil Pan, Cure for Transmission Overheating?

 Nissan Titan Large Capacity Oil Pan, Cure for Transmission Overheating?
By Annie Sam

If you are an avid MotoIQ reader you will have read how transmission heating problems while towing in my Nissan Titan has lead our editor to purchase a Toyota Tundra.  When Nissan first introduced the Titan, it was a half ton truck like no other with performance and towing capacity that were best in class by a long shot.  In fact it was the Titan that triggered a war in performance in the half ton truck category among the manufacturers that the Tundra is currently winning.  No matter, the Titan is still a good truck, especially if its major weaknesses can be fixed.

Getting stuck on the side of the road in the middle of summer on the Baker grade while trying to get to a race gets old real fast.

Without forcing you to read about our Nissan Titan's transmission woes, basically the trucks major problem is that the transmission temperatures get very high when towing going up long steep grades such as the notorious Baker grade and the Grapevine, especially in the summer time.  We have experienced this even though our Titan has the factory tow package which has two oil coolers, one in the radiator and an oil to air unit in the front of the truck. Since we have to climb over the Grapevine to get to Buttonwillow where we race frequently, this is quite an issue.  We have been forced to stop several times to let the tranny cool as to not damage it.  When it’s hot in the summer and you are tired and want to go home or are eager to get to the track, this sucks.

The added volume of the PWL oil pan on the left is obvious when compared to the stock pan on the right.

Strangely we have noticed a puzzling phenomenon, it helps if you go faster up the hill; we have noticed that the transmission temps drop significantly if you maintain 70 mph.  This is not always possible as you often don’t have the power to go up steep grades this fast, not to mention that it's 15 mph over the California towing speed limit. We also noticed lower transmission temps when we manually down shifted into lower gear and revved the engine higher instead of leaving the transmission in drive.  This indicates that something must be slipping when the transmission is left in drive although no obvious slipping can be felt.  It’s not the best thing for the engine or for fuel economy though.

We also didn’t seem to overheat the transmission in the first 30K miles that we had the truck, although our heaviest towing in hot weather was after this point.  Note that we never tow anywhere near the truck's 9000 lb capacity, our average towing weight is usually under 5000 lbs. 

This is what the OEM countermeasure finned diff cover looks like.  Nissan used this when fixing Titans with warranty claims and it came on all Titans after the second year of production.  If your diff cover looks smooth and you tow, you had better get one of these or one of the good aftermarket higher capacity units or you will be sorry!

We are not alone in our problems.  The Titan is notorious for overheating its tranny and rearend, especially when towing near its maximum capacity. So what to do?  Our Titan has the later Nissan countermeasure differential cover which is an alloy piece with fins and a slightly larger capacity.  It is imperative that you use a premium oil for the Nissan differential as it runs hot and the factory fill is high quality synthetic gear oil. We replaced the 60,000 mile old OEM fluid with 2 liters of Royal Purple synthetic gear oil in the 75W140 weight as recommended by Nissan.  If you feel that you need more oil cooling or capacity, PML makes a diff cover with .75 quarts more capacity, Stillen makes a part with 7/8 quart more capacity and Mag Hytec makes a cover that holds a whopping 3.75 quarts more than stock and comes with a dip stick.  If your Titan comes with an old style unfinned cover, and you tow, you need to invest in the finned cover or one of these aftermarket parts.

We used Royal Purple gear oils and Amsoil ATF for this project.