HELP needed with GMC transmission problem

On Jul 5, 11:33 pm, Terry <[email protected]> wrote:
> My 2000 Sierra just started having a problem with a server jump from
> 1st to 2nd gear.
> When starting from a dead stop and my automatic goes from 1st to 2nd
> on take-off, I get a very bad jumping jerk of the truck.
> All other gears are good.
>
> To get around the problem I began starting off in 2nd gear from a dead
> stop.
>
> Any help is appreciated.
> Terry in Texas

Do you have a 4L60E transmission? Is this a 1/2 ton truck? If so,
this could be the dreaded P1870 code. Get the codes scanned because
iirc the P1870 does not always trip the check engine light. This has
something to do with the valve body boring out the valve sleeve. If
the trans isn't too far along, a Sonnax valve-sleeve installed by a
good, independant transmission shop might save you from a complete
rebuild. I am sure someone else in this group can explain it better
as I am certainly no transmission guy.

HTH,

Derek

My 2000 GMC Sierra truck started having a problem shifting from first
to second gear. The other gears are fine.
The whole truck shakes when it goes into 2nd gear.

UPDATE: I found out the next day that it was working okay and it
hasn't done it again since.
So I'm thinking that once the truck is hot, is when it's going to do
it again.

any ideas?

Terry in Texas

Terry <[email protected]> wrote:
>My 2000 GMC Sierra truck started having a problem shifting from first
>to second gear. The other gears are fine.
>The whole truck shakes when it goes into 2nd gear.
>
>UPDATE: I found out the next day that it was working okay and it
>hasn't done it again since.
>So I'm thinking that once the truck is hot, is when it's going to do
>it again.
>
>any ideas?

Does the shudder happen when you put the clutch in, or when you take the
clutch out, and does the shifter move evenly or do you have trouble
getting it in?

If your clutch is not disengaging completely, this sort of thing can
happen, and it's always much worse going from first to second than
on the other gears.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Jul 10, 3:59 pm, Terry <[email protected]> wrote:
> My 2000 GMC Sierra truck started having a problem shifting from first
> to second gear. The other gears are fine.
> The whole truck shakes when it goes into 2nd gear.
>
> UPDATE: I found out the next day that it was working okay and it
> hasn't done it again since.
> So I'm thinking that once the truck is hot, is when it's going to do
> it again.
>
> any ideas?
>
> Terry in Texas

Get the codes scanned. The valve body issue is only when the trans is
hot. When cold it should act "normal." You might have a time bomb
here but if you act quickly, you can avoid a complete rebuild.

On Jul 11, 9:58 am, genius <[email protected]> wrote:
> On Jul 10, 3:59 pm, Terry <[email protected]> wrote:
>
> > My 2000 GMC Sierra truck started having a problem shifting from first
> > to second gear. The other gears are fine.
> > The whole truck shakes when it goes into 2nd gear.
>
> > UPDATE: I found out the next day that it was working okay and it
> > hasn't done it again since.
> > So I'm thinking that once the truck is hot, is when it's going to do
> > it again.
>
> > any ideas?
>
> > Terry in Texas
>
> Get the codes scanned.  The valve body issue is only when the trans is
> hot.  When cold it should act "normal."  You might have a time bomb
> here but if you act quickly, you can avoid a complete rebuild.

My 2000 Sierra is a automatic.
Thanks,
Terry in Texas

My son had the same problem with his 97 GMC K1500. He had the trans
rebuilt and the problem was still there. They replaced the valve body
with a new updated one from GM and it worked perfectly. He said that
after the valve body was replaced the trans never shifted better. You
may be able to just replace the valve body on your's and not have a
complete rebuild. If you do it yourself, there are allot of steal
balls on top of the valve body when you take it down, be careful not
to tip it over and misplace any of the balls. Hope the info helps.

Warren