wisdom of lock up converters

[KParsons]

I would like to hear anyone's thoughts on lockup converters pro and con. I have had my stock 06 for a year now,7k miles. The trucks in my past are all autos since 1980. fFord ,Chevy , Dodge -all gas. None of them had any kind of lock up, i can see it in top gear. But it seems unnecessary. I am not hard on my trucks , but i will push them if i need to. The hunt and peck the transmission goes through, seems a waste of time. I still have not put my pac brake on yet. I was wondering if you can get rid of the lock up in 1-3 gears? kp

 

[BHolm]

There is a pretty good chance you have had autos with a lock up convertor, unless you stopped buying trucks in 1980. Pretty much all of them went with a lock up convertor when they went to four speeds instead of three. That would include most trucks built after about 1988 or so.



The pros are simple, less heat, better economy, better transfer of power. I can't really think of any cons and can not imagine why you would not want this feature If you plan to run an exhaust brake with an auto trans you must have the convertor locked or it will a) overheat the trans b) not provide effective braking because of the slip.

 

[Buffalo]

My first Dodge/Cummins was a '91. 5 W-250 with a 4-speed auto. , non-lock-up TC. It was horrible. Especially towing in the mountains. On a good grade, it would not go over 47 mph. with the 25' travel trailer hooked on the back.



I spent a small fortune trying to upgrade the power, thinking it was the underpowered little 6 cylinder engine not making enough power to haul the trailer uphill. I, even, upgraded the TC by having Hughes Torque Converters rebuild my stock unit. I don't remember exactly what the stall speed of the stock TC was but, it was way too high. That TC was built for higher revving gas motors. The low revving Cummins never got enough rpm's to create enough 'grab' to pull the load uphill. That stock TC DID create some big heat, though. Hit 270 degrees at the top of many hills.



The Hughes, rebuilt unit had much more 'grab' to it. But, only at low rpm's. Like at a stoplight, it wanted to go & sometimes, I had to really stand on the brake pedal. Towing in the mountains, there was no improvement, at all. So, for $600/700, all I got was an undesireable effect. (In Hughes TC defense, I understand they have a TC that works much better than what they built for me, now. )



After all this effort, I decided that the engine was making enough power & that the power just wasn't getting to the rear wheels. The main power loss was in the TC. So, I started a search for a lock-up TC.



At my first May Madness ('02), I ran across Clint Cannon from ATS transmissions & explained my problem. He said that it would not be a problem. Later that summer, I drove to Denver & had them install one of their units in my truck. Turned out that it was their first attempt in a first generation Dodge. It worked beautifully!!!



I now can take the same hills, easily at 55+ mph with no problem, at all. Could go faster but, their is no need. Now, the engine even sounds different because ALL the power is getting to the rear wheels. What a difference!!!



I understand that the DTT TC's work very well in the 1st gens. but, I was afraid to try one because of the experience with the Hughes unit. Didn't want to duplicate that experience & expense. However, today I would not be that afraid.



If you need to get all the power to the rear wheels that the Cummins makes, you will DEFINATELY need a lock-up TC, in my opinion. It made a world of difference in my truck.



I feel so strongly about being able to lock-up the rear wheels to the engine that when I bought my '03, I got the NV-5600 6-speed, because I did not want to have to, eventually, incurr the expense of an aftermarket auto. trans. They are expensive but, they DO work!!!



Hope this helps.



Joe F. (Buffalo)

 

[KParsons]

clears that up

thanks for the info, all my old gasers were 3speed auto,s no lock up . kp

 

[BHolm]

The reason the 48re is so busy is because it is a bit of a dinosaur. It is based on the old 727 with obviously a lot of updates. It would be preety tough to make it both smooth and durable, that is part of the reason why it has been replaced with the new six speeds that have fully integrated electronic controls. Complexity is way up but so is the quality of the performance.