I also own a 2000 Venture with the same problem. The pressure switch
is inside the transmission and you are looking at about $30 part and
$750 labor charge.
GM will not help you on this COMMON problem.
Changing the trans oil a number of times does not help, I have tried
I understand "dirt/varnish" builds up in the pressure switch which
keeps it from working correctly.
When the trans is cold, it shifts correctly. The problem appears to
get worst with heat.
This problem does not cause a trouble light or check engine message to
come on. However, if the dealer plugs his GM scanner into your car,
THEY can pull a code and will know the pressure switch is no good.
When we had our van "scanned" they told us the pressure switch was bad,
the good news is the transmission is not slipping.
The dealer also offered us $1,500 on a trade-in. Not a very good
investment on our part!
Apparently you cannot "hide" a problem from GM's scanner.
I then made several trips to Walmart and AutoZone looking for a "fix in
a bottle". Nothing worked.
A few days ago I ran into a product called "TransTune" for $6.15 with
tax. This product was different than the other products I tried. It
cleans "gum and varnish".
The directions on the bottles were not clear.
It said "use 1/2 of a can and drive 5 miles" then change the trans
I wanted to use a full can, maybe more than one can! I called the
company. The guy I talked to was the son of the original inventor. I
told him I wanted to use more than one can to "really clean the
pressure switch out". He would not even let me use a full can, just
1/2 of a can.
Within the first mile I could not believe how well the trans shifted!
It has never shifted so smoothly!!!!!!!
I then jumped hard the gas and the trans still shifted smoothly.
Since I have added the product, we have not encounter any hard shift
and the problems appears to be FIXED.
Best $6 I have ever spent!!!!!!!!!!
If the trans oil needs to be changed, use a 1/2 can, drive a week,
replace the oil and filter and then but the other half of the can into
The details on the product can are as follows:
Product name: TRANSTUNE
Sea Foam Sales Co.
PO Box 5178, Hopkins MN 55343
If it works on your van, spread the word.
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