How hot should your Allison transmission run?

If you own a 2001-2004 LB7: Your normal operating temperatures will run around 160-180 degrees.  These transmissions will warm up when towing or driving in the summer months. 200-225 is very common when the ambient air temp is 80-100 degrees and your transmission is under an increased load. Temperatures from 230-240 have been reached with no damage to the transmission. If you are seeing temps above 225 degrees on a regular basis you should check your fluid level. Fluid levels too high may cause excessive temperature. Higher mileage transmissions or trucks using aftermarket tuners with increased power may be experiencing converter slippage and will see increased heat. A quality replacement converter and or a full transmission upgrade may be required.

The 2004.5-2010 LLY, LBZ, & LMM: This transmission will run at a higher normal operating temperature than the LB7 models. Normal operating temps will range from 180-200 approx. 100 degrees above ambient air temps. These transmissions will run from 200-230 in the summer months when towing in hilly areas. These temps are normal and will not hurt the transmission. If you are seeing temps above 235 degrees on a regular basis you should check your fluid level. Fluid levels too high may cause excessive temperature. Higher mileage transmissions or trucks using aftermarket tuners with increased power may be experiencing converter slippage and will see increased heat. A quality replacement converter and or a full transmission upgrade may be required.

Service time?
Your owner's manual recommends servicing your Allison every 30k miles. An Allison transmission should never be flushed. The internal filters should only be changed when rebuilding the transmission or changing pans. The correct way to service your Allison is by draining and refilling with quality fluid, we highly recommend Transynd Synthetic Transmission Fluid. During service, you should also remove and replace the external filter. Be sure to clean and reinstall the magnet on top of the external filter.

Larger transmission coolers and deep sump pans?
Aftermarket Allison trans coolers are inexpensive and effective in reducing some trans temps. They must be Allison specific not universal. You may destroy your transmission by using the wrong cooler. Higher capacity or deep sump trans pans will help reduce some trans temps and hold additional fluid.

DmaxStore carries a full line of Allison transmission OEM and aftermarket products.