It will help-you can control lockup in Drive and OD. Unless you have a moded VB it will not lockup in 1 or 2. Mine has been modded so I can L/U in 2-3-OD. It will help "slow you down" when locked, but you need to be aware that if the T/C slips you can kill it.

 

I don't have personal experience with this but my understanding is that yes locking the TC will reduce Trans temp. However I'm not sure how well the stock TC will take being locked under heavy load. I'd guess you'd be okay locking at above 30 mph but that is truly a Wild *** Guess. For me, I'm waiting 'til I know I have a TC that'll take it.

As far as engine braking goes it may reduce temp but I don't think you'll get much braking either way, apparently diesels just don't engine brake like gassers. I do know a TC lock helps a true Jake/pac brake work and may even be required for full functionality.

 

It is my understanding that it will help alot during towing as well as if you want to go NOW!!. I do not have mine yet (and I'm sure someone will correct me if I'm wrong) but I think you hit the switch as soon as you get into 2nd. It will up shift 2-3 and 3-4 in lockup. Once you are in 4 (OD) it will not down shift so you have to take it out of lock up or you will stall the motor. If you have OD turned off or have not achieved OD it will down shift from 3-2 and 2-1 but you will again need to disingage it or you will stall. Hopefully someone will stop by and correct any part of that that is wrong so we don't have to learn the hard way.

 

NOT RECOMMENDED on a stock transmission!!!! Only lock it up once you are in D or OD. Locked shifts have broken many an input shaft.

 

Can the D - OD shift be done in lock up without busting shafts? What VB mod need to be done to allow 2nd gear lock up? If I have to do more moding to my VB and can't make at least a d-od shift locked I just may be wasting me time running the wire.

 

Your stock VB will go from 3 to OD locked up with a switch. It is a "noticeable" bump, but not to drastic. Overtime I think you will be tempting fate on stock shafts. If you want to lock up in all gears or whatever, I would go buy a good VB.

 

i have a stock TC but I also have a DTT valve body, is there any way to get it to lock up in 2nd like it does in 3rd, the stock TC is so inefficent(sp) when it does lock up it just like hitting the power band on my dirt bike, I wouldn't want it to shift locked up for fear of breaking a shaft, is there any way to do this?

 

What is the difference in VBs that allow the 2nd gear lockup? I don't have an after market but mine is kited. Is there a mod that can be done?
If it breaks it breaks I will have a legitimate excuse for a full build!

 

Is there any way to get the TC to lock up in 2nd, 3rd, but have it unlock to shift to avoid breaking a shaft. Is the TC locked when it shifts from 3rd to OD? Or is there at leasta way to get it to lock up sooner in 3rd maybe right away?

 

My trans always shifts from D-OD locked, any throttle position. In fact it always shifts from 2-3 locked also. I have no switch and it never stalls coming to a stop. It is never locked in 2nd however. I dont know about busting shafts, but I dont tow heavy and I always am accelerating WOT. Havent broke a shaft yet, but I have no clue if they are stock or what I got. Bret