Intermittent hard shifting
Intermittent hard shifting I've searched and can't seem to find any info relating to my specific problem. Car is a 98 Formula and just recently, and without warning, the trans will start shifting really hard. P-D and 1-2 being the hardest. Just had the pan dropped and flushed, new lines, rear yoke seal and trans mount, but the problem exists. I haven't done any programming on it, things bone stock. It's intermittent, might start doing it first thing ,later on down the road, or in a day or two. Driving me crazy. Don't know much about trans, so any suggestions will be greatly appreciated.
Teching In
Joined: Apr 2008
Posts: 7
Likes: 0
Intermittent shifting problems I don't know if its the same issue, but my wifes 2000 was doing the same thing. It seemed intermittent and started randomly. But I am able to reproduce/prevent it from happening.
She noticed that if she quickly decreased speed on the highway from ~60mph to 20 or so, that the 1-2 shift was always hard, snapping the car forward, and the 2-3 Shift would be hard sometiems as well. However if she lets the car coast, or gradually slows from 50-60 down to local traffic speed after exiting the freeway, then the 1-2 and 2-3 shifts are nice and smooth.
Her car is also throwing SES light, when i looked into it, it said it transmission slipping. I think it was pcm 1750? not 100% on that.
If I slow from 70 to 25 hard, it will shift hard every time. If I slow from 70 down to 30 in say, 10 seconds or more, it works perfect.
I am thinking it is my valve body. But I'm not a mechanic, and I am going off of other peoples reported issues. And, this might be completely unrelated to your problem. I just remember the frustration I had trying to figure out the cause. I too also had the pan dropped/cleaned and fluid flushed/changed. Still didnt fix the problem.
Hope this helps.
She noticed that if she quickly decreased speed on the highway from ~60mph to 20 or so, that the 1-2 shift was always hard, snapping the car forward, and the 2-3 Shift would be hard sometiems as well. However if she lets the car coast, or gradually slows from 50-60 down to local traffic speed after exiting the freeway, then the 1-2 and 2-3 shifts are nice and smooth.
Her car is also throwing SES light, when i looked into it, it said it transmission slipping. I think it was pcm 1750? not 100% on that.
If I slow from 70 to 25 hard, it will shift hard every time. If I slow from 70 down to 30 in say, 10 seconds or more, it works perfect.
I am thinking it is my valve body. But I'm not a mechanic, and I am going off of other peoples reported issues. And, this might be completely unrelated to your problem. I just remember the frustration I had trying to figure out the cause. I too also had the pan dropped/cleaned and fluid flushed/changed. Still didnt fix the problem.
Hope this helps.
Have it scanned and look for code 1850. Torque convertor clutch is worn. The pcm reads this as the tranny slipping and ups the line pressure giving you hard shifts. A pretty easy fix but you need to fix it......
It's been scanned, no codes other than O2 sensors, which has been the case since the long tubes. Someone told me the throttle position sensor could/might cause a problem with the trans. Anyone heard of this?
It's an 1870, and most cases the torque converter is not the problem.
TECH Regular
Joined: Mar 2009
Posts: 420
Likes: 0
From: Ricerville
+1 for the P1870 code. When that happens, I think the PCM commands max line pressure for the trans, so it will shift hard. Also, it disables OD and TCC lockup.
That is exactly what would happen on my 96 3.8 Firebird. I used to have to pull into a parking lot or something like that, and stop and restart the car. This wouldn't clear the 1870 code, but it would usually get the trans out of that mode.
That is exactly what would happen on my 96 3.8 Firebird. I used to have to pull into a parking lot or something like that, and stop and restart the car. This wouldn't clear the 1870 code, but it would usually get the trans out of that mode.
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Teching In
Joined: Oct 2009
Posts: 3
Likes: 0
My car just started doing this tonight.....Hence why I signed up. I was driving home nothing seemed out of the ordinary, then slowed down a bit, and as soon as I started to accelerate again, it started to shift HARD. Guess going to get it scanned tomorrow to see if it's throwing a code. If it is, how hard is it to clear it?
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