Keeping Torque Converter Locked???

I just added a switch to my f250 for similar reasons. Not a difficult mod and I will use it only when towing.

Thanks Brian,

My truck is equiped with a "Juice With Attitude" and I can control all parameters of fueling, EGT, boost etc. So I can keep a good eye on conditions and if parameters are exceeded then the JWA will "de-fuel" the engine and keep me out of trouble.

At over 600 pounds foot torque, I think I'll be ok with a locked up converter at 40 - 45 mph. This is about the only time the truck downshifts. Even with a 10,000 pound tow, it never downshifts at highway speeds. Even in the mountains out west. Amazing truck and engine!

Just remember that a 2006 vehicle is highly programmed and very smart. You won't do a mod that does better than what the engineers put into it. At 40 - 45 mph your drivetrain obviously needs the torque multiplication of the unlocked torque converter in some situations. At steady speeds it probably is locking, ask it for small speed variations or go up and down a little hill, and it unlocks. 200 degrees is not hot for an automatic trans. Locking the converter and forcing the engine to develop more power than it needs to at low rpm will increase EGT, probably not to a danger point but higher than they should be.

Brian

Here is a "How To" on installing a torque converter lock up switch on a 3rd gen Dodge Diesel

http://www.cumminsforum.com/forum/3rd-gen-powertrain/107415-3rd-gen-mystery-switch-diy-works-great.html

Top-A-Cal...Thanks! Great explanation. Obviously you know this stuff and this isn't your first rodeo!

Bucky...Up hills at 40-45 mph on back roads

I'm thinking about installing a Torque Converter lock-up switch as is detailed in many threads on the Dodge Diesel forums. Just need to remember to turn it off as speeds decrease or you come to a stop. It would act like forgetting to put the cluch in on a manual transmission.

At what speeds is this happening? BTW, nothing wrong with 200 degrees. My Dodge is older buts locks up in 3rd and OD. Owners manual could be a source of info for you.

The converter slips when not locked and does less RPM than the engine. That's where heat is produced. So the heat is cooled by the fluid and the transmission cooler. The fluid must be clean to keep heat from being held in any particles present in fluid due to breakdown of components the transmission is made of and condensation caused by heating and cooling. Fully locked is no slipping and moving with the engine 1 to 1. Newer transmissions that are fully locked in all gears, use a wet system to switch gears by double clutching so fast that they switch to engine RPM without friction like torque converters produce by slipping in all gears except high gear. I've known transmission rebuilders to drill holes in the converter to allow more fluid through which fastens and gets closer to a lock than the slower fluid produced by factory design. So the heat registering is the engine working to hard, using more fuel to get the speed that a locked transmission would yield better MPG at cooler temps. Also transmissions will not go into high gear if the engine temperature is appearing to low through a bad temperature sensor signal from the engine block, causing heat buildup in transmission and engine and bad MPG.