Why does a 1997 Chevrolet Astro Van transmission change hard into 2nd gear after it gets warm?

Answer 1

First, I am not a mechanic. However, I am technically inclined and have owned many astro/safari vans. Hopefully the following is at least informative.

-The astro's 4L60e transmission has a very wide gap (change in gear ratio) from first to second; thus, some lurch forward is normal

-Transmission Fluid flows more quickly/easily when it is hot. Typically, gear changes and clutches engagement/disengagement will happen more quickly when the fluid is warm than cold.

-A quick, firm and positive shift is preferred to a seamless long shift. The quicker the shift, the less the transmission friction material will be worn over time.

How many miles are on the astro? Has the transmission fluid and filter been changed regularly (every 25,000-40,000 miles)?

-If the clutches or friction bands are worn, the friction surfaces may become "catchier/grabbier" when hot. I have experienced this with clutch surfaces in warn differentials before.

-If the transmission has not been serviced in a couple years, I would recommend dropping the pan, cleaning the pan, changing the filter, and filling it with 5+ quarts of Mobil 1 full synthetic ATF. You may also try adding 1/2 or a full bottle of Lucas transmission fix with the new fluid. It supposedly helps bring some life back to warn friction bands.

Good luck, post any success.

Joel

i had the same problum with my 1994 astro van cost me $1400.00 to find out that the problun was in the computer i got a used computer from the salvage yard and for 100.00 i had to switch the long chip at the bottom of the boardwhith the one from mine and it has been running fine ever since hope this info helps Henry