Engine/Transmission (1994 - 1998) Mystery switch with stock auto

[yenga80]

I've searched and read lots of threads on the mystery switch to lock the TC. I found info on tst's website to wire up a switch. First question what kind of switch and in what location works best for you? I've read about putting one next to the O/D switch next to the cup holder; one on the floor to toggle with your foot; one on the gear shift stalk.

Second question and most important is will this do any damage to my stock transmission? Only fueling mod to the truck so far is #8 tst fuel plate. Afc is stock as break off screw is still intact. I do plan on upgrading the transmission some day but the stock transmission is doing great.

Thanks!

 

[KB0OU]

I have a toggle switch right next to the O/D lock out switch. If I am going up or down long steep grades I can push the O/D switch and lock up in the lower gear, helps the brakes going down and pulls good going up without a lot of heat. As far as your stock transmission, it will work fine as long as the transmission works ok, don't put too much power through that transmission. I have the DTT torque converter and a built up transmission and I have had no problems running 300 HP. I have 420,000 mile on the truck.

 

[champspa]

you have already done the best thing with the tps delete . the lockup switch doesn't work that good but that's just my opinion .

 

[cerberusiam]

Second question and most important is will this do any damage to my stock transmission?

It has the potential to destroy the transmission if you are not very careful. Unless you build the trans up somewhat it will slip clutches, stress the input, etc. You have enough TQ stock to snap the input shaft in the right conditions. Don't even think about using it to help braking or you will take out the direct clutch pack. You would have to modify the VB to get lockup in anything other than drive or OD and both of those gears need help before forcing the issue.

 

[yenga80]

Okay thanks for the info guys

 

[KB0OU]

champspa,

I will have to dissagree with you, I think the "mystery switch" is a very good mod, and cheap to do. I don't use it much here in Missouri but I used it a lot when I was hauling out West and to Alaska. When you have a good size load behind these pickups and get into big mountains you need all the help you can get to ease down the mountains and when pulling them being in lockup on the torque converter clutch is very important in reducing heat produced. You do need to upgrade the Auto transmission from stock for it to work good with the horsepower the Cummins can produce but the transmission will handle it if properly built up. Like I said I run right at 300 HP which is real good for getting around with a load and I have not had to do anything to the transmission but change fluid and filter for 350,000 miles in the 420,000 miles the truck has on it.

Any real good shop that knows that transmission can upgrade it for you, and you need a good low stall TQ like the DTT that I have.



Good Luck