Surging Silverado

[tcbuckner1]

I have a 2000 Silverado Z71 5.3L....I bought this truck brand new and have taken very good care of it and it has rewarded me with over 170K miles without any major service. recently though it started surging around 45-50MPH....I tried to eliminate the small stuff...here is what I have done

 

plugs, wires, fuel filter, O2 sensors (yes all 4),

 

I think that I have narrowed it down to the torque converter lockout.....my quesiton

 

can I simply disable the lockout solenoid to test my theory...if so where is it located and what is the best way to do this. Also what ramifications might I have to leave this disabled other than possibly a SES light or reduced fuel economy?

 

I plan to eventually fix the source of the problem but I will probably want to rebuild the trans at the same time.

 

any help or input would be greatly appreciated

[svensk]

Make sure it isn't a intermittent misfire instead. I had a very similar issue last year (40-55mph), ended being a misfire after having the transmission specialist drive it.

could be leaky intake gasket, EGR, etc.

[2500sierra]

If it is the TCC, i dont think there is a simple way on the 4l60e to disable it, i know on the older 700r4 you could just unplug them, but these new transmissions are PWM (pulse-width modulated) so you cant unplug them.

 

A good transmission shop, with a high dollar scanner should be able to turn off the TCC (tourque converter clutch) solenoid. for ya and that would tell. The solenoid is located on the valve body right under the pan.

 

The only downsides to no TCC, are poor fuel economy, and it will heat up the tranny alittle more in OD, espically if towing.

 

Possible underline causes for this ive found are, Bad TCC solenoid or wireing to it, bad TCC out of round bore in the VB, fried TCC clutch, or defective TCC clutch piston. Either way maybe replacing a valve body or torque converter.

http://www.transmissioncenter.net/4l60e.htm the screen shot is the part you may need, i screen shotted it because that tranny parts page is super long.

 

This is about all i know, because my truck has intermediate lockup problem, its super annoying, just wait til your transmission realizes that a component is slipping, it will start shifting super hard once it sets the soft code.

 

dont quote me 100% on everything, this is just the info i could rustle up from forums on it. but hope it helps

[tcbuckner1]

Thanks Guys!!! I will look into these other potential sources of the problem first and report back my findings. I really want to eliminate the easy stuff before I have to get into the trans.

[noahraysanders]

I have a 2000 Silverado Z71 5.3L....I bought this truck brand new and have taken very good care of it and it has rewarded me with over 170K miles without any major service. recently though it started surging around 45-50MPH....I tried to eliminate the small stuff...here is what I have done

 

plugs, wires, fuel filter, O2 sensors (yes all 4),

 

I think that I have narrowed it down to the torque converter lockout.....my quesiton

 

can I simply disable the lockout solenoid to test my theory...if so where is it located and what is the best way to do this. Also what ramifications might I have to leave this disabled other than possibly a SES light or reduced fuel economy?

 

I plan to eventually fix the source of the problem but I will probably want to rebuild the trans at the same time.

 

any help or input would be greatly appreciated

 

My truck is doing the same thing 40 -50 mph it surges... i just got the transmission rebuilt about a year ago. if it is a tcc problem how much is the cost for a shop to fix? is it something easily corrected in your driveway or is it a pain in the but?

[2500sierra]

it could be a PITA if its your torque converter i wouldnt consider it a driveway job. If its a valve body bore issue that takes good talent and skill to do rite but removing the VB and taking it to the tranny shop for them to rebore it would be the guaranteed fix. Or you could install a reman VB for under 300$.