Just recently I posted a message about my pulling a 23 Ft trailer with my truck. I have another question or two regarding the same subject. If I pull the trailer around the 5000 lb limit(give or take a 100 lbs or so)and pull it about every 6-8 weeks, will this shorten the life of the engine and tranny even though I change fluids sooner than normal? I'm getting about 12 mpg towing with it and I hate to get rid of the truck especially with the gas prices the way they are and the truck runs great. I've never had a problem with it and I have 68K miles on it. Also, the truck hangs pretty low in the rear with it on. I bottomed out a few times going up the I-5 on my way to Sacramento. I was looking at the Timbren Suspension Enhancement System that is advertised in Mr.Trucks website. Which would be better to get? The Enhancement System or put a few more leaf springs on? I don't want the ride to be rough without a load and I've heard that with additional leaf springs it will be rougher.

Do you have an automatic transmission? It sounds like moderate use for towing, which if you don't haul in the mountains shouldn't hurt your truck if you do change the engine oil, tranny oil, diff. oil more often, even changing to synthetic fluid. I'd recommend using SuperSprings. I like them better then Timbrens or air bags. SuperSprings will work as a torsion stabilizer improving handling like an anti-sway bar. And for leveling out your load, they will automaticly adjust for your trailer and not effect your empty ride. Read my article, http://mrtruck.net/springs.htm Thanks

I have an automatic tranny. I'm changing my engine oil now (even before I started towing) every 3000-4000 miles and the tranny oil when Toyota states it should be done. How much more often should I change the tranny oil? I don't ever recall them changing the diff oil? Thanks for all the great info you've been giving me.

The rule of thumb is to change tranny and diff oil twice as often as the manual says when towing. On larger trucks, they will show two oil change intervals one for normal use and one for severe duty.