# Automatic Transmission shifting problems **URL:** \ **Category:** Factual Questions\ **Created:** [December 24, 2004, 12:13am UTC](https://boards.straightdope.com/t/automatic-transmission-shifting-problems/281406 "2004-12-24T00:13:29Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Improv\_Geek](https://avatars.discourse-cdn.com/v4/letter/i/b3f665/32.png) [@Improv\_Geek](https://boards.straightdope.com/u/Improv_Geek)\ **Post date:** [December 24, 2004, 12:13am UTC](https://boards.straightdope.com/t/automatic-transmission-shifting-problems/281406/1 "2004-12-24T00:13:29Z")
Alright, so I’ve searched the forums and found a few things which danced around the topic but I am hoping I can get this nailed on the head. I’ve got an old van, 1993 Chevy G20 Custom van, and the transmission has recently begun having trouble shifting from second to third gear. It goes from first to second without trouble, but to get to third I have to over-rev the engine and then let off the gas and then give it a small bit of extra juice for it to catch the third gear. Is this a sign of a need for a rebuild (prays for the answer to be no)? If not, what is it a sign of? Thanks ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [December 24, 2004, 2:48am UTC](https://boards.straightdope.com/t/automatic-transmission-shifting-problems/281406/2 "2004-12-24T02:48:26Z")
> [@ronincyberpunk](#): > > Alright, so I’ve searched the forums and found a few things which danced around the topic but I am hoping I can get this nailed on the head. > I’ve got an old van, 1993 Chevy G20 Custom van, and the transmission has recently begun having trouble shifting from second to third gear. It goes from first to second without trouble, but to get to third I have to over-rev the engine and then let off the gas and then give it a small bit of extra juice for it to catch the third gear. > Is this a sign of a need for a rebuild (prays for the answer to be no)? If not, what is it a sign of? Thanks Sounds as if the shifter mechanism is acting up. Take it to one or two of the automatic transmission specialists for a test and estimate. ---
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [December 24, 2004, 3:40am UTC](https://boards.straightdope.com/t/automatic-transmission-shifting-problems/281406/3 "2004-12-24T03:40:43Z")
The symptom you’re describing is called ‘flaring’. Start with the simple and cheap stuff. Replace the fluid and sump screen/pan gasket. Your modulator may also be in question-GM used to use vacuum modulated transmissions-not certain if they did in '93. If you’re a handy person, this can be done for \<70$. If you aren’t a handy person, you have my condolences. :👍: ---
**Author:** ![Improv\_Geek](https://avatars.discourse-cdn.com/v4/letter/i/b3f665/32.png) [@Improv\_Geek](https://boards.straightdope.com/u/Improv_Geek)\ **Post date:** [December 24, 2004, 11:56am UTC](https://boards.straightdope.com/t/automatic-transmission-shifting-problems/281406/4 "2004-12-24T11:56:47Z")
I got the fluid changed, I didn’t change the filter / screen yet. Unfortunately I’m not a handy person, but we’ve got a family mechanic so he should hopefully not give me a thrashing when it comes to price… Thanks guys. ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [December 24, 2004, 4:05pm UTC](https://boards.straightdope.com/t/automatic-transmission-shifting-problems/281406/5 "2004-12-24T16:05:12Z")
I had a similar problem with one of my cars in the past. A few capfuls of acetone cut through the gum and varnish making things stick in there, and shifting was sweet once more. ---
**Author:** ![ParentalAdvisory](https://avatars.discourse-cdn.com/v4/letter/p/53a042/32.png) [@ParentalAdvisory](https://boards.straightdope.com/u/ParentalAdvisory)\ **Post date:** [December 24, 2004, 5:24pm UTC](https://boards.straightdope.com/t/automatic-transmission-shifting-problems/281406/6 "2004-12-24T17:24:56Z")
> [@danceswithcats](#): > > Your modulator may also be in question-GM used to use vacuum modulated transmissions-not certain if they did in '93. Since it’s a '93 GM van, I’m gonna say that it’s a 4L60, and that it does have a vacuum modulator.