Silverado Knocking

[jshibe]

I have a 99 Silverado 1500 with a 3 inch body lift and 285s. Lately I have been hearing a knocking noise coming from the transmission or the rear end. I think that it is in the rear end. It only does it from first to second and it only does it after I have ran the truck for about 30 minutes. It shifts really hard from first to second and it makes a popping noise. Has any one ever encountered this problem or have any suggestions? Thanks
Justin

[nnunez]

I have the same problem....but this seldom happens. No knocking though. Just a serious pop to the u joints from the hard shift. I've had people look at it with no results. The tranny may be telling me its tired but I will run it until it dies.

[jshibe]

Yeah that is what I have too. How many miles does your truck have on it? Mine has 104000. Someone told me to change the transmission filter because they think that junk is building up on it when I run it and when I shut it off then it frees up. I just dont know and I dont like how it sounds.

[75K30]

Is this knocking actually related to he shifts? IS this noise actually coming from inside of the transmission, or is this just a case of a bad u-joint or something really minor?
Also that truck uses a 4L60E transmission, and the 1-2 shift solenoid is known to be troublesome. They are also known for a failing harness / plug assembly, as they get old and the connection gets a little dirty.
A good code reader can be very helpfull here.
Those tires are not very large, but even at the size they are, and given the mileage on the trans, I would feel very lucky to have 100K miles on the clock without a re-build so far. I see these fail with less than 100K on them quite often.
Lack of maintenance is usually the killer.

[jshibe]

Yeah it is during the shifts and the U joints are not bad. It is only between first and second and if I shut the truck off after it does it and restart it, it does not do it. Im thinking it is electrical. All of the fluids are good.

[nnunez]

My truck has 165k miles. Now, keep in mind that it will not do it all the time. It only does it when it wants to do it. My Fifi is a spoiled brat and only acts up when she wants.

The knocking that I hear is the rear end when it engages. It is a big bump similar to being at a dead stop, putting it in neutral, reving it and then put in drive with higher than normal RPMs.

Long ago, I had a van that did that only after the tranny was replaced. I drove it like that for 10 yrs too.

Good luck in repairing it and if you figure it out let us know what the problem was.

The tranny shop did recommend that I DO NOT change the tranny filter though. They implied that with that many miles it may do more harm than good to open up the tranny...........

Originally Posted by jshibe

Yeah that is what I have too. How many miles does your truck have on it? Mine has 104000. Someone told me to change the transmission filter because they think that junk is building up on it when I run it and when I shut it off then it frees up. I just dont know and I dont like how it sounds.