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I feel like this has been discussed to death, but still can't seem to find the specific answers to my specific issue. 94 4-runner V6 2wd, 250,000 miles. A friend rebuilt the trans and we put in new TC. I just put a new engine in (block and heads), new thermostat and water pump, and a new PS pump. Old trans was mighty burnt but he cleaned the whole thing up and it shifts great except no lock up. I was having lock up issues before the rebuild but I could finesse the throttle and get it to lock up. Before the engine rebuild it was starting to stall randomly at lights for no apparent reason at least once each day I drove it. No shudder or anything, it would just stop running. After new engine, rebuilt trans with new TC and a boat load of $$$, it's still stalling and no lock up. Checked ETC, TPS, TV (aka Kick down) cable (it has a real good snap-back on the cable, adjusted it every way I could think of) even took out the Normal/Power switch next to the gearshift and cleaned it all up. No codes. It's mighty frustrating but I LOVE my '94 and she's super clean and never in a wreck ... interior looks new, so I'm committed to this relationship! Oh, did I mention I've been to too many trans shops to count and all they do is drive the living hell out of my brand new engine and then blame it on the injectors or worse, scratch their heads and say "I dunno". And I pay them for that??!!! Thanks in advance!
The Throttle cable has nothing to do with lockup (or "kickdown") (it controls how hard the transmission shifts. The shift points themselves are controlled by the ECU.) But good to check it.
The ECU won't command lockup with a cold engine. So if the ECT (ETC?) is not read correctly, it won't shift to lock up. How did you test it?
Hey scope, how did you know the average "I dunno" cost exactly $149!? Ha ha. As I understand it this is electronically controlled lock up. Tested the engine coolant temp sensor by pulling it out and dropping the lead into hot water and following the readings on my voltmeter. Seemed to spec out OK, plus the guy that did the motor said it was fine. Thanks for the computer tests ... I'll do that this weekend. Could I have a valve body issue and if so is there a way to check without pulling it? THANKS FOR ALL YOUR HELP! This is frustrating ... especially the stalling part. I was making a left turn at a non-controlled intersection, yes, on a blind curve, where the speed limit is 50 (which means 80) and it stalled just as I started my turn. Lucky nobody was coming and I was able to start it in N without any problems, but jeez ... stalling sucks!
Did you check the two transmission fluid temp sensors(NOT the temp switch that activated the light)? One is on the transfer case and the other is by the Park/neutral/gear selection switch.
Check the wire harness and the plug for damage, I have seen some where the harness has been rub and worn through sections.
check it all the way over the trans, That leads to the O2 sensor and if its damaged it can cause the engine to also stall.
Examine both sides of the trans plug for burn or oxidation marks and maybe spot some of the terminals with di-electric grease before plugging back in.
Thanks Punchy ... exactly what I was looking for and will check it out tomorrow. Went to a (another!!!) trans shop Friday and the tech was really cool and spend about 40 minutes with me - NO CHARGE - and admitted he was a little stumped, but at least we have narrowed it down to no lock-up. OD is working fine. He said it really felt like it wanted to lock-up. If not the A/T fluid temp sensor, then I guess it's time to pull the valve body ... it was mighty burnt and might just be worn out. Anyway, I'll crawl under there tomorrow and check out that sensor and the wiring and report back!
Sorry gang ... can't find it on the passenger side ... is it on top? The only other obvious things I could find are in the second pic on the driver's side at the very back.
While the A340H has an AT Fluid temp sensor, this page http://web.archive.org/web/200812091...20electron.pdf says the A340E does not. At a minimum, if there is a temp sensor, it doesn't influence shifting in an A340E.
So why, again, are you looking for one? Lock-up is controlled by ECT, not AT fluid temp. If it were me, I'd go back to the beginning and run the FSM tests in order. That's why we have a manual.
04-25-2017, 12:20 PM
