Bit Of A Clunk When Starting Off In 2nd

[VMaxtastic]

My 2000 4.8 did the exact same thing. If I have the gear shift in 2nd and hit the gas, there will be a dead spot in the gas pedal, followed by a clunk as the truck lurches into motion.. Is this common? It sure seems to be considering both my GM's have done it. Should I take it to the dealership?

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My 2000 4.8 did the exact same thing. If I have the gear shift in 2nd and hit the gas, there will be a dead spot in the gas pedal, followed by a clunk as the truck lurches into motion.. Is this common? It sure seems to be considering both my GM's have done it. Should I take it to the dealership?

 

 

Yeah, when you put it in 2nd, it starts in second, I think. I don't know if mine clunks or not. I don't ever put it in 2nd, just drive, it is an automatic.

[VMaxtastic]

Thats what the mechanic told me about my 4.8.... that its starting in second. Perhaps a sensor that isnt working properly was what the guy told me. But like you said... I use 3rd in the city and D on the highway.. but the odd time I'll put it in 2 instead of 3 and not notice till I take off from a stop.

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Thats what the mechanic told me about my 4.8.... that its starting in second. Perhaps a sensor that isnt working properly was what the guy told me. But like you said... I use 3rd in the city and D on the highway.. but the odd time I'll put it in 2 instead of 3 and not notice till I take off from a stop.

 

 

No, when you put the gear shifter into second, it starts in second. That's how it's supposed to work. This is not true with third, though.

[VMaxtastic]

Why though? I don't see the benefits of it. Unless starting on a hill with a load maybe? Its not really a clunking noise it makes I guess. It just jolts a bit like something is slipping. The sensation is identical to my 4.8, even after I put a brand new tranny in it it still did it.

If its normal then thats great to know. That is why I'm on this forum after all. We all drive the same trucks.

[Gregs]

i had the same problems, read up on greasing the transmission output shaft that fixed my problem.

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Why though? I don't see the benefits of it. Unless starting on a hill with a load maybe? Its not really a clunking noise it makes I guess. It just jolts a bit like something is slipping. The sensation is identical to my 4.8, even after I put a brand new tranny in it it still did it.

If its normal then thats great to know. That is why I'm on this forum after all. We all drive the same trucks.

 

 

I don't know why it works that way, but it does and it's supposed to, if you want it to start out in 1st move it to 1st then to second. All those gears are really there for though is downhill degenerative braking.

[VMaxtastic]

Thanks greg... That search answered some other questions I had too.

[oldscsc]

Second gear start out is particularly useful in the winter in slippery conditions (less torque = more traction taking off). Second gear start was actually an option on the GM W-body lineup in the early-mid 90's, among other cars.

[redvett]

Second gear is the fail safe mode on the 4L60e & THE 4l80e TRANSMISSIONS.

[GPSilverado]

When most late model 4 speed GM transmissions are driven from a stop in 2, the truck will start in second. If you try to accelerate very quicky in 2 from a stop, the truck will downshift to first. That could be the clunk that you are experiencing.

[Stevens03]

I think the clunk your hearing is actually coming from the lockers locking up with the low torque applied. I've heard it too.

[ColoradoSkiCountry]

If there is a clunk there from when you take off in 1st gear, it's likely the slip yoke. GM was supposed to have fixed that issue around 2003/2004 with a different type of nickle plated slip yoke, they also changed to the blue transfer case fluid which helped smooth and quiet things down alot. Not sure why it would be happening on a 900 series truck.

[demonchevy123]

Have you checked you U-joints?