98 LS400, Transmission Hard Shifting
 

Hi, I have a 1998 LS400 with about 86,200 miles on it. Normally, the transmission shifts smoothly through all the gears from a complete stop. However, if I slow down between 5-10mph and accelerate again, the car jerks harsly before getting into the next gear. This is especially frustrating when driving in rush hour traffic or in parking lots, having my car lurch forward when driving slowly.

So far, I've drained/refilled the transmission with Toyota T IV fluid, but the condition doesnt seem to improve. The engine and transmission mounts on the car have also been replaced. I'm curious if the problem is not the transmission, but the TPS or something else. I'm baffled by this issue :confused: and any suggestions would be greatly apprecited.

check the rear bushing on the diriveshaft

also think about FLUSHING the trans

It sounds to me like it might be a problem with the ECT (drive-by-wire) rather than the transmission itself.

ECT is the transmission controller the drive-by-wire is a different system.

I'm pretty sure Toyota uses the ECT name for both the transmission and throttle.

I own a transmission shop in Miami,Fl and have ran into this problem a few times.... First have a shop with an OBD II scanner that has the software to get into the TRANSMISSION side (not same as gen codes or driveability) check for gear ratio error code,If there clear code and drive again POOF! 99 out of 100 problem is gone! usually caused by playing with or bumping ECT power switch/OD cancel switch or moving selector during shift. ECM reads SLIP and sends pressure solenoid to Max to preserve unit.... Best advice do not ride around with hand on shifter and keep Li'l crumb snatchers in back seat away from pretty brite lites...Big Rob

The problem you speak of is very common with 98-00 LS. I had the same issue on my 98. Theres not much you can do about it... it used to really bother me when i drove through neighborhoods, and traffic. The only thing you can do to alleviate the situation is using the snow mode to ease things up.

The 98-00 had drive by cable... not wire, as there is a physical cable running from the peddle, all the way to the butterfly.

The 01+ has drive by wire (via electrical sensors), for both the brakes, and throttle.

Hello Everyone!

I just bought a very low miles 2000 LS Platinum Edition. I'm changing out the strut bar cushions soon as it was obvious from the first highway drive, they need attention, but the hard shifting transmission at low speeds has me worried about commuting in heavy traffic. Other than parking lot lurching, it drives like a new car in every other respect.

I'm looking at buying a $24 bluetooth code reader on amazon that has 1,000 plus rave reviews that communicates wirelessly to any android device, to clear any transmission codes that might be there. Some are saying that I need one that plugs into the transmission itself.

Does anyone know what specific capabilities I should be asking of the manufacturer before I buy one? If autozone can read the code, can they clear it for me or will just give me the code?

Thanks ahead of time!

Debbie

If it shift hard just check the tranny fluid and do a couple of drain and fills of tranny fluid. Make sure to use Toyota T-IV fluid. Is the check engine light on? Any code reader should be able to pull codes.

There are no codes showing on my base reader from Harbor Freight. There is no CEL light or any other warnings.

The car came from a full service from an Audi Dealer in Orlando after it was traded in there last month.

The reason I am thinking transmission full lock up like the previous guy above said, is that I bumped the shifter with my elbow quite a few times and knocked it out of position, while making the long trip back home to Michigan. Nothing out of the ordinary driving until I got stuck in a traffic jam when almost home.

That is when I noticed the sensitive throttle and hard shift when crawling along or starting and stopping.

Used the slap shift feature a dozen times getting back on the highway too, to feel that VVTI surge.

I've used line locks and driven drag automatics before. It definitely feels like an auto with a shift kit in it now.

Tonight I am going to take it to auto zone and then after crawl under and look at the drive shaft coupler.

Edit: The trans fluid is clear as new motor oil, and sits 1/4 inch past the top fill mark when read after a long day driving in hot weather, with car in park on level ground. Audi changed the passenger side valve cover gasket while they had it during prep for sale.

Just came back from autozone, they could not find any codes either. Their reader had an option for Toyota and still nothing. Theirs reads airbag codes, but there was no special transmission category.

Switched the car to snow until I got on main roads and the difference is dramatic. Nice smooth driving and no feeling the gears shift. As soon as power or normal is selected it is back to unpredictable and hard shifts.

Hit it hard in snow from a stop and it was Lexus smooth, but with 100 less horsepower IMO.

Will I hurt anything running it in snow on dry pavement and at freeway speeds?

Based on the hard launch in snow setting and no lurching, I didn't bother jacking the car up tonight and checking the drive shaft coupler.

Believe it or not, it may be related to the post #489 here.
I have experienced several shift problems when ECU capacitors begin to fail among 98-00 Celsiors. Most of those were fixed as is silos5 has done.

Other than that, a badly clogged throttle body and injectors confuses the ECU and it often causes a too low idle as well as a gear engagement problem. In this case, the engagement is too slow at very low speed.

Thanks for the suggestion! I'll read that thread and see if it pans out for my 2000.

Edit: Wow that looks like a surgery level fix! How easily is the ECU reached in the car? Also, used units are a no go from what I surmise, as they are probably failing too or about to.

Edit 2 : Looked at more related posts. ECU is a bear to remove it seems, so I'll try your test method instead first. Now I need to find the capacitor. I've already got a nice digital multimeter. 😆

my 99 also has this hesitation (causing a lurch) , but being in my 80's, I just make a full stop and then go on my way, most folks see my gray hair and make allowances for me... but I am watching this post to see if I can do anything to get rid of it

Get rid of what Billy? The Lurch or the Gray hair?