Automatic Trans Problem

Any ideas?? I have a 1991 toyota 2wd 4cyl. automatic with 75k on it.
Recently I have encountered a shifting problem. About every 3rd time I
drive the truck it will go up to an abnormally high rpm before it
shifts into the next gear. I tried shifting it manually and that
doesn't work either. When it does shift it slams into the next gear.
I don't know enough about mechanics to know where to begin. Do these
transmissions have a speed sensor??
Thanks for the help. Peter

<peterbmason@aol.com> wrote in message
news:1138197117.069553.17720@g47g2000cwa.googlegroups.com...[color=blue]
> Any ideas?? I have a 1991 toyota 2wd 4cyl. automatic with 75k on it.
> Recently I have encountered a shifting problem. About every 3rd time I
> drive the truck it will go up to an abnormally high rpm before it
> shifts into the next gear. I tried shifting it manually and that
> doesn't work either. When it does shift it slams into the next gear.
> I don't know enough about mechanics to know where to begin. Do these
> transmissions have a speed sensor??
> Thanks for the help. Peter
>[/color]

Just curious: Are you the original owner of the truck?

I am the 3rd owner.

<peterbmason@aol.com> wrote in message
news:1138201741.584368.61360@g14g2000cwa.googlegroups.com...[color=blue]
>I am the 3rd owner.
>[/color]

OK....I asked because 75K miles sounds odd for such an old vehicle, and it's
even stranger for a tranny to go bad at that age, unless it had been abused.

<peterbmason@aol.com> wrote in message
news:1138197117.069553.17720@g47g2000cwa.googlegroups.com...[color=blue]
> Any ideas?? I have a 1991 toyota 2wd 4cyl. automatic with 75k on it.
> Recently I have encountered a shifting problem. About every 3rd time I
> drive the truck it will go up to an abnormally high rpm before it
> shifts into the next gear. I tried shifting it manually and that
> doesn't work either. When it does shift it slams into the next gear.
> I don't know enough about mechanics to know where to begin. Do these
> transmissions have a speed sensor??
> Thanks for the help. Peter
>[/color]

Start by checking the trans fluid level and condition. Is the fluid at the
full mark ? Is the fluid clean or dirty ? Does the fluid smell burnt ? Has
the trans fluid ever been changed before or is it still the original fluid ?
If the fluid was changed was the correct fluid used ?

That means the friction plates(clutch pak inside an auto trans) is
going bad and starting to slip. You'll be needing another trans soon,
or have yours rebuilt.

[email]peterbmason@aol.com[/email] wrote:[color=blue]
> Any ideas?? I have a 1991 toyota 2wd 4cyl. automatic with 75k on it.
> Recently I have encountered a shifting problem. About every 3rd time I
> drive the truck it will go up to an abnormally high rpm before it
> shifts into the next gear. I tried shifting it manually and that
> doesn't work either. When it does shift it slams into the next gear.
> I don't know enough about mechanics to know where to begin. Do these
> transmissions have a speed sensor??
> Thanks for the help. Peter
>[/color]
I'd try draining and refilling the transmission, cleaning with
[url]www.auto-rx.net[/url], then a complete flush and refill. This works very
well if the problem is due to varnish buildup or stiff sealing
parts. If there is mechanical damage, you'll need a rebuild soon.


Ken