Rough Downshift
02-04-17, 06:47 PM
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Rough Downshift
Hi guys,
I have a '99 GS 300 with 118,500 miles. I've had it for the last 15,000 miles and it's been super good to me.
The transmission fluid was flushed at about 109,000 miles.
My car has always shifted hard from 2nd to 1st when going up hill. My in-laws live up a steep hill and have a long driveway on the hill with a gate in the middle. When I come to a complete stop things are smooth, but after sitting on the hill for a second if I let me foot off the brake theres a hard thump as it drops into first, which it seems to do at a weird time.
Anyway, I always figured that was the hill and never thought twice about it.
Recently though, after the car is all warmed up, if you're going 30-40 mph and step on it, it will struggle a bit to downshift, then eventually it will do it but the actual shift seems to take a long time (not necessarily how long before it shifts, but the duration of the shift). Today when I left work, while leaving driving through the large parking lot it shifted into second very quickly like normal, but when coming to a stop it downshifted into first pretty hard.
Everything was fine through a 7-8 stoplights until I got to the grocery store, again as I was slowing to nearly a stop, thump, hard downshift. Went to leave the parking lot, same thing, thump, hard downshift. Drove through 4 more stoplights and a couple of stop signs home without any harsh shifts, very smooth.
I'm not sure where to start here. Seems to be intermittent in the rough shifting, but I can't find out why it's doing it.
Any help is greatly appreciated. Thanks guys.
I have a '99 GS 300 with 118,500 miles. I've had it for the last 15,000 miles and it's been super good to me.
The transmission fluid was flushed at about 109,000 miles.
My car has always shifted hard from 2nd to 1st when going up hill. My in-laws live up a steep hill and have a long driveway on the hill with a gate in the middle. When I come to a complete stop things are smooth, but after sitting on the hill for a second if I let me foot off the brake theres a hard thump as it drops into first, which it seems to do at a weird time.
Anyway, I always figured that was the hill and never thought twice about it.
Recently though, after the car is all warmed up, if you're going 30-40 mph and step on it, it will struggle a bit to downshift, then eventually it will do it but the actual shift seems to take a long time (not necessarily how long before it shifts, but the duration of the shift). Today when I left work, while leaving driving through the large parking lot it shifted into second very quickly like normal, but when coming to a stop it downshifted into first pretty hard.
Everything was fine through a 7-8 stoplights until I got to the grocery store, again as I was slowing to nearly a stop, thump, hard downshift. Went to leave the parking lot, same thing, thump, hard downshift. Drove through 4 more stoplights and a couple of stop signs home without any harsh shifts, very smooth.
I'm not sure where to start here. Seems to be intermittent in the rough shifting, but I can't find out why it's doing it.
Any help is greatly appreciated. Thanks guys.
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tiguy99 (02-05-17)
02-08-17, 09:31 PM
#3
09-05-18, 08:01 PM
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Location: Indiana
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Replace ECM
Had similar issue on my 3rd gen. After some research, found out the ECM computer needed replaced. Found a company on Ebay that sells refurbished plug and plays. $300 and an easy DIY and was back running nice again. 06 GS300 195K
Last edited by stel009; 09-05-18 at 08:09 PM. Reason: Clarifying some info.
09-08-18, 08:49 AM
#5
I too have an occasional hard downshift from 2 to 1 on my 98 GS4 with 112k. In my case the issue only shows sometimes when driving at very slow speeds. I don’t think anything mechanical in the drivetrain causes this since the issue is so infrequent. My guess is a shift solenoid in the trans, but I have not been able to confirm this yet reading thru threads here. Other thoughts on infrequent hard 2 to 1 downshifts cause?
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