Axiom Home Page Forums General Discussion The Water Cooler Change transmission fluid in my vehicle.

My father in law has the same problem, same truck.

I have a 00 Chevy S10 that I've been fighting with the "Passlock" system. There's been numerous accounts of folks having the same problem and no action from GM to make things right. My brother just called me and asked if I knew what "Passlock" was. It's hard to think that the same problems keep cropping up with no proper response from GM.

Hence GMs predicament....

I really wanted to "buy American" when I replaced my van this past Fall, but the Dodge/Chrysler just wasn't in the same category as the Honda in terms of build quality/design. At least the Honda is built in the U.S....

What I couldn't figure out was that Gm/Chev kept reinstalling the same defective part. When my brother had his ABS fail on his '05, I figured GM is still using the same design on their sensors (mine's '01)and I should add that my brother had to pay for his repairs(not warrantied or recalled as it should have been). This is, to me, a serious safety issue that should have been fixed permanently/redesigned years ago when problems first came to light.

I have never liked ABS and wish it was still optional on the vehicles I bought recently so I could have opted out.

Adrian, I had been thinking this, too. PCV valve, gunky throttle-body, etc.

Randy, when you start noticing the symptoms, can you put it in neutral, rev the engine and see what happens? I had a somewhat similar problem with our Ford Windstar that turned out to be an oxygen sensor. Obviously, if the engine revs freely from idle to redline, that is not the problem, but it might be worth checking.

PCV valve, mmmmm possibly, unlikely, it would show up at idle speeds more than cruising speed as would a gunky throttle body.

I checked out a couple of sources for similar complaints with his Isuzu, the most common for driveability issue(not a surging issue though) has been a corroded Engine Coolant Temperature sensor wire, the fun part is the sensor and subsequent wiring are under the intake plenum. I can remember doing one a number of years ago, I remember thinking the engineers were out to lunch the day they decided to put this sensor under the plenum. I did see a few complaints of surging, hesitations, etc., unfortunately no fixes were posted, but I have seen some unhappy owners having to rebuild their transmissons at 80,000 - 100,000 miles, which in my books isn't that bad anyway, well 80,000 is a little short but 100K(although most do go well beyond now adays) is what most cars are designed to live to, anything beyond that should be looked upon as gravy. Of course if most of the driving is highway the the mileage will be increased substanially before breakdown.

The light throttle at cruising speeds causing the surge is a pretty good indicator that the torque converter is hunting or your OD trannie band is slipping. If the truck was older, it could be the vacuum module for torque converter lock up. I think they went electronic in the late 80’s, early 90’s and have been pretty fool proof.

But…if it was torque converter related, you would not feel as if the wind was pushing the rig back. The engine RMP would pick up to compensate and you’d notice that. I can’t help but think this is your OD band slipping.

Can you actually hear the engine hesitate, cough, sputter, miss or anything unusual? If you could verify if it is the engine or not, that would help. Low RPM cruising speed surges can be caused by a multitude of different thing. Vacuum leaks come to my mind first. It’s not the PCV, but if you want to check, pull it and look for milky goo (emulsified oil) in the valve cover. You can usually see it on the PCV…

It’s not your fuel line. You’d be missing and sputtering all the time, right before the engine died completely.

I can remember replacing the TCC switch on the old THM200's from the late 80s and early 90s, it was always the first thing to disconnect when the complaint was surging at highway speeds.

I have a 2000 Silverado Z71 never had a single problem.

Knock on wood!