C6 initially wouldn't shift and now 1st gear binds up

C6 initially wouldn't shift and now 1st gear binds up

Joined: October 2nd, 2004, 3:33 am

May 14th, 2011, 11:43 pm #1

I have a C6 behind a 460 that started going directly from 1st to 3rd. Then it began starting out in 3rd and I could pull it down to 1st, but it would still skip 2nd when shifted manually. I changed the vacumm modulator and it still starts in 3rd, but now it locks up when I shift it into 1st.

Any suggestions on where to look first? I assume probably a clutch pack is now stuck causing the lockup in 1st, but not sure what caused the intial problem of starting out in 3rd.

I can't complain, it has lasted about 8 years with street and dragstrip use so I guess it's just time for a rebuild.

Thanks,
James
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truck doctor
truck doctor

May 15th, 2011, 6:50 pm #2

the high clutch is likely welded together.
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James
James

May 15th, 2011, 8:00 pm #3

Thanks for the response Truck Doctor.
I figured the final outcome was probably a clutch siezed when 1st started binding. I am just not sure how I got there from the transmission skipping 2nd on the upshift. Something may have been causing it to be in two gears at once.

I'll see when I tear it down.

James
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truck doctor
truck doctor

May 15th, 2011, 10:57 pm #4

obviosly if second was sliping to a point that it shifted from first to third, then when it went into third it was sliping goin in as third gear was working harder by shiftin in early. it's kinda a result of the overall wellness of the tranny. mabe it should have been taken apart when second started to crap out. it just shows how severe these tranys can get worn befor final death.
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James
James

May 16th, 2011, 1:23 am #5

Truck Doctor,
It all happened pretty quick. It began acting up about 20 miles from home and it seemed like it might be the vacuum modulator so I changed the modulator and then 1st gear locked up when I test drove it.

It lasted for 7-8 years of street and dragstrip usage so I can't complain. I was going to freshen it next winter anyway. These are pretty tough transmissions.

Thanks,
James

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truck doctor
truck doctor

May 16th, 2011, 11:15 am #6

well to get seven or eight years of pounding on the track well what can i say you got 6-7 extra years out of it.
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