Torque converter slow to lockup?

I've got something strange going on with my 2002 3.2, auto, 43Kmi. The torque converter takes a ridiculously long time to lock-up in 4th/OD. Once it does lock, it occasionally goes in/out of lockup seemingly at random @ steady hywy speeds. You barely feel it and might not even notice if you didn't look at the tach, or had the radio turned up. She runs like a top, shifts as smooth as butter, no CEL or check trans light, decent MPG's, PRND32L lights are perfect. The only oddball thing I've noticed this winter is the heat kinda sucks. She does heat up and the temp gauge registers right in the middle, but the heat output is mediocre to say the least. I know TC's wont lock until the engine/trans warms up. It's an emissions thing as the engine/trans & cats supposedly heat faster in unlocked mode. Do you fellas think this could be bad coolant thermostat given the fairly weak heater output? I wouldn't suspect an IMG as she starts, idles and performs perfectly in all conditions. The trans range sensor is also not a suspect as the PRND32L lights are perfect. I'm stumped & I hate to pay the dealer to 'troubleshoot' as we've dumped ~$700 into our other car in the last 6wks. :banghead: Oh and as far as trans service goes, I did an ATF swap (3pan drains/fills) @ 15Kmiles and paid the dealer to do a 'trans service' @ 24Kmi (one drain/fill) A bit overboard I know!:rolleyes:

Thanks
Joel

My truck is also experiencing the low cabin heat issue right now, just started this problem last night into today. If you look at the update in my thread, I believe that's the reason, water pump's had it's day - least that's what I'm suspecting it is.

With your's I'm not 100%, my original thermostat was still good when I opted to rid of it just for safety sake at 118k miles - I think it lasted so long because I've had new antifreeze put in every 28-30k miles like clock work; or, could have just been pure luck.

However, on our Toyota that was the 1st sign of a failing thermostat followed by headgasket issue - BUT, the engine never got hot, OR at least according to it's gauge. The cabin in that truck would NOT warm up for the life of us, and before we could see other signs we had no clue what was causing it. We did 2 radiator flushes, replaced some hoses, had good heat for a FULL day, truck was running good - then she popped a tall-tell leak.

I know you've checked the obvious levels of fluids, so the only other thing I can think of is it it's just way too cold in your region combined with a short drive?? Thermostat and/or, and yes it's been known to happen :crying:, a failing water pump. Believe it or not, my 1st Rodeo, 3.1L had a failing waterpump at 24k miles.

..only other thing I can think of is it it's just way too cold in your region combined with a short drive?? Thermostat and/or, and yes it's been known to happen .

It hasent been too bad the last 2 weeks. Anywhere from 30-55degF. I have a 30mi commute to work, 23mi of which are interstate hywy. It's been taking about 10-12 miles for the TC to lock. It never did that before :uhoh: . The heat really doesnt feel any worse either.

Thanks
Joel

Hmmm, something's up.

Any CEL codes?

FWIW - since I changed all O2 sensor's, tranny's shifting at clear/precise points, and readily downshifting sooner then it has in a while. Feels normal again, whereas when the old sensor's were in downshifting came after acting like it was lugging a bit.

Wondering if you've got a weak sensor and it's just not showing yet; I swear I've felt symptoms long before any codes popped up.

My truck has always put out good cabin heat, with the exception of only a 5-10 mile drive on a -0F day; but heat output increased after the flush, gets hotter quicker.

A 30 mile drive is definitely more then enough, even on a cold day.

Share some of those 55F temps would'ya??

If you can do it yourself, and save some $$$, flush your radiator and throw a new thermostat in and check all hoses, least that's a start. But, I'm not positive that it IS the cooling system, but it will start to narrow things down.

Also, one other thing, make sure you're using good fuel and not a mom/pop shop; I've had my share of bad gas that has given some pretty wicked symptoms - like stalling out at a paytoll on 75mph highway!

At least you're truck is dumping the nasty green goo - wondering if all night I shouldn't just start pricing a new I-380, Nissan Frontier, or Nissan X-terra. I don't know where it is that's leaking, but it's bad!

Keep me posted on your rig!