2005 Chev Silverado 1500 4.3 2wd, 164,000KM

Im pretty sure it is the torque converter/ Tranny but i am curious if other people have had this prob.Or think im off my rocker lol

Ill start off by saying i did a tranny flush a while back, and the old fluid was as black as Engine oil! And it was slipping haha No metal parts in the pan though.

Anyways, I notice it most at 60 and 80 km when the truck goes into lockup at 1100rpm. It vibrates the truck in a way that all the panels inside the cab hum.

I dont know how else to describe it, the truck doesnt shake or vibrate like a unbalanced wheel or u-joint. It just vibrates all the panels in the cab to the point where they hum. Once the truck is above 1100rpm/lockup it wont hum.

Now when im driving at 80km the engine is at 1100 rpms/lockup, and the truck is huming. i keep my speed with the right foot, and touch the brake with my left. Turning off the lockup,
The hum is gone!

Does this sound like a Torque Converter?

I've Checked engine mounts, and im going to check tranny mount and u-joints...but i just dont think their my problem.


ANY THOUGHTS GUYS? Is this normal for a V6?

 

I also suspect something along those lines. Torque converter or flywheel.

What happens when you brake torque it when you're at a stop? Doesn't matter if you burn rubber or not, just hold the brake down hard and give it some throttle.

Have you actually checked your u-joints?

 

Ill try that today.

I havent checked the u-joints recently..just about due for oil change so i will check them, i check them every oil change and they have always been good( only have had the truck for a year). And the vibrating hum has always been there.

Ive had the hood up and loaded the engine up in gear, watching it to see if the engine moves. Both in forward and reverse, loaded the engine up it does not move at all. So i know the engine mounts are good. But i still need to check tranny mount.

 

30 Common 4L60E Transmission Problems & Repair | Charlotte NC

I believe #25 applies to your symptoms.

 

Nullhead
I tried holding the brake and getting on the gas, truck just grunts to try to overcome the load being applied.

RUFFNECK4LYFE
That sounds EXACTLY like my prob.
But would the tranny fluid being black effect anything else? Say Clutch packs? Do you think a complete rebuild be best?
I just dont wanna put a converter in it and one of the clutch packs goes or something else goes.

 

Any Transmission guys on here have any thoughts? Should I rebuild it or just put a Converter in it?

 

Well I'm taking a transmission class at my school right now. I wouldn't call myself a transmission guy though ... If you're doing the work yourself, throw a torque converter on it. If you're going to have a transmission shop do the work, let them do their own diagnosis, repairs and what ever they want. They'll offer you some sort of warranty at least.

Just my 2 cents.

 

Do a flush and new TC, if it still does the same thing, then it may need a rebuild. But Im no expert on trannys. The fluid being that dirty is probably from the clutch packs. If you get it rebuilt, install a very good cooler for the trans. No. 1 killer is heat. I have mine cooled and romped on it and every time I change fluid it is pretty clean. So its hard to say, I would just get it rebuilt with a warranty to have some peace of mind.

 

I think for the peace of mind and warranty, im gonna get it rebuilt. Plus i dont wanna pull the tranny twice haha

I appreciate ur help and thoughts guys, THANKS!!