tc lockup

[tmar04]

how can I tell, for sure, that my TC is actually locking up? I feel all the shifts up to OD, which happens at 45 mph, dthen nothing after that. No computer codes present. A4ld shifts smooth, engine runs great and smooth, just wondering about the TC.veh is 87 2wd B2 2.9L. No tach to observe.thx.

 

[BRUTUS_T_HOG]

it helps to have a tach.

i just drive lightly until it shifts through all the gears and then very lightly try to accelerate.

if the engine lugs without revving more then the TC is locked. if it revvs then its slipping or not locking.

if you try to put too much load on it then the TC would unlock or the trans downshifts

 

[bonedoc]

Too the best of my knowledge, all the overdrive is, is the locking of the torque converter clutch. Drive the truck, get it to cruising speed and let it shift all the way up. Then downshift the auto shifter from OD to D. If you hear it downshift then you were in overdrive.

 

[ChopTop84]

Too the best of my knowledge, all the overdrive is, is the locking of the torque converter clutch.

No. There are 4 distinct gear sets in an A4LD, plus the locking TC. The TC locking could almost feel like a 5th gear depending on how firm the lockup was.

I dont know much about the a4ld locking command from the computer. If its a simple on/off command, then you might feel it, but on most of the fords with a locking TC I have driven, the computer uses a pulse width modulation (PWM) command to gently lock in the TC clutch. Little more difficult to notice.

Also, depending on computer code on late model stuff, the lockup could happen as early as the 1-2 shift, below 45mph. Thats how my superduty is, and then I put a manual lockup switch, and two LEDs to give me visual on what the computer is doing, and what Im doing if I manually lock it up myself.

 

[tmar04]

thanks to all for input. I installed a manual on/off toggle switch. problem solved for now.