tc lock up

[ehines218]

So a couple weeks ago I put a lockup switch in my truck and finally tried making a hard run with it. i locked it at a stop sign and then floored it. as soon as truck shifted to 2nd gear it slammed 3rd and bogged the engine then shifted into OD just like it should. ive tried it running around town and it does the same thing. if i lock it while in 2nd it shifts to 3rd locked real quick. what is going on here it is really frustrating and have no clue why lock up is causing a shift. also my transmission doesnt do 2nd lock so it cant be that.

 

[Nighthawk]

So a couple weeks ago I put a lockup switch in my truck and finally tried making a hard run with it. i locked it at a stop sign and then floored it. as soon as truck shifted to 2nd gear it slammed 3rd and bogged the engine then shifted into OD just like it should. ive tried it running around town and it does the same thing. if i lock it while in 2nd it shifts to 3rd locked real quick. what is going on here it is really frustrating and have no clue why lock up is causing a shift. also my transmission doesnt do 2nd lock so it cant be that.

You answered your own problem, its called stacked shifts due to valve body setup. I would suggest some reading is done before your trans ends up scattered all over the road.

 

[97$moker]

You have to modify the valvebody to do 2nd lockup, otherwise only lockup In 3rd and od. Since its in 2nd and you commanding lockup its shifting to 3rd so it can lockup. There is a thread on here showing what to do to get 2nd lockup.

 

[ehines218]

O ok. I just figured that it would drive normally and then do a locked 3rd shift and locked 4th shift. I didn't know it would try to go to 3rd. Why will it drive normally in 1st then.