Hi all,

I have a 1998 with the 5 speed.

The transmission is not shifting as it is supposed to, I guess.

When is is shifting up in gear, sometimes it is not smooth. This depends on throttle input.
Sometimes it is jerky. With that I mean my head gives a little notch forward, and I can feel it. Other times I can't even feel it.

Downshifting is no issue at all.

Transmission pan was removed to replace filter.
Filled again with Toyota IV oil. (Oil level is correct. )

Which resulted in no change in shifting.

I know that either my motor mounts, and or transmission mount need to be replaced.

No codes.
Checked different sensors on the throttle body, which seems to be in spec.

Have someone experienced something similiar?

Thanks.

 

How many miles on the car?
It sounds like you need to establish where the “jerking” is coming from. The transmission itself, internally, or from a compromised rear (trans) mount. Rear trans mount failure is very common on the LS but most ppl just live with it. Possibly the most notable symptom of a faulty rear mount is a profound CLUNK when shifting from P to D.

 

Car has 153000 miles.

When shifting from P to D it is quite noticable. So at some point I need new mounts.

But when the transmission is upshifting, it feels like it is related to throttle/load.

My first thought was it might be the TPS, but that is in spec according to the scanner.

Thank you for the anwser.

 

MY 2-3 shift has always been the most jerky shift. Some shifts are better quality than others. Also depends on revs\throttle input, that can vary the shift quality as well. Sometimes it's nearly imperceptible, other times you do get a little kick.

It's hard to judge how much of a kick is "normal" vs "something is wrong".

If you get a clunk from P <--> D, yes you need transmission mounts. I replaced mine and it made a big difference. Partly in shift quality, mostly in "tightening" up the driveline for when I give it gas from a dead stop. I think it's like 50 or 60 bucks and 15 minutes to replace.

Also if you rev the engine in park\neutral and you feel any vibration what-so-ever, that means you need motor mounts as well. The allowable tolerance for vibration is zero. Those make a HUGE difference. Makes the car's power feel much more effortless because of the eliminated vibrations.

 

The 2 front mounts can be a PITA to replace. That said, start with the rear (trans) mount which is both cheaper and easier to replace. Most of the time it will solve your clunking woes and you may not need to mess with the 2 front mounts.

 

400fanboy.

That sounds exactly the same as I am experiencing.

I took it for at drive with the scanner connected, and watched what gear it was in. And 2-3 is the "worst"

 

Replacing the mounts are a good idea.

But it doesn't feel like a mount related issue, atleast not when it is upshifting

That kick you get from the shifting is very annoying.

 

So you don't have any codes although the AT is not working right. My idea is to check the 5.0V Vcc's ripple level in the ECU. An ECU for a 98-00 tends to show some rough gear shifting problems when the ripple level reaches to 150mVp-p or so.

At the initial failing stage of an ECU for a 98-00, the engine still runs good but the AT doesn't behave as it should. The best measuring method is to use an oscilloscope and connect it to the MAF sensor's Vcc line. Another quicker but a bit rough method is this.

One idea is simply to replace QAS (Quaternary Ammonium Salt) capacitors unconditionally if the ripple measurement can't be done comfortably. The lifespan of an ECU for a 98-00 is longer than a 89-97 due to the lesser stress to QAS capacitors but QAS capacitors are prone to fail someday due to the character of used material quaternary ammonium salt. Those don't last longer than conventional electrolytic capacitors because the QAS becomes very strong alkali as it ages due to the dry-up. A smart guy would replace those capacitor as one of preventive measures.

 

Good suggestion.

I will try to measure the ripple. That should atleast give me some info about the health on my ecu.

The tps sensor says 14.9% when pedal position sensor is disconnected. So that is good.

I tried to remove the negative from the battery to clear the shift pattern from the ecu.

That actually helped, for a bit. Holds gear longer, and a smoother shift between gears. It is like when it shifting, it is too soon. But it shifts anyways, because not enough throttle is applied. (If this makes sense?)

I usually drive pretty slow.
I also have the problem when turning into a corner, and then hitting the throttle, nothing happens until 1500rpm.

Propably need to clean throttle body/"intake" for injectors.

​​​​​​Thanks for all the suggestions so far 👍

 

That symptom is often caused by the clogged air mix path. You definitely need to clean the throttle body as well as the air mix path which is consisting of 9 small halls and 2 larger halls as is shown below.

 

Aisin A650-E transmission image depicts two filters within valve body.

Their existence suggests they perform some function.




Attached is pdf containing additional images of valve body.

There appear numerous "check bslls" (deliberately misspelling to avoid cyber nanny)

If check bslls worn, perhaps shift quality affected.

 

Yes exactly Yamae.

That is a possibility Yodaone.

When shifting "manual" from 2nd to 3rd, it is just not very soft.
3rd-to4th you can't even feel, only hear it.

Otherwise i have no other problems. Nothing with idle or rough engine.

Only transmission.

When I can get my hands on a capacitor/oscilloscope, I will try to test the ripple.

Thank you.

 

So I did some testing today to refresh my memory

>25% throttle, above about 2600rpm. If a 2-3 shift happens above that, it's a bit rough. It's a fast shift, that kicks you a bit, where it feels like the clutches are grabbing too quickly and not perfectly in sync with the engine.

>75% throttle, above about 4000rpm, if basically any shift happens above that, it's a bit rough.

Wide open throttle at redline ish, it's a crapshoot. It's a slow sluggish shift, but generally speaking smoothly handled.

Anything not listed is basically imperceptible in terms of shift quality\feel.

I'll keep an eye on this thread to see developments.

 

">25% throttle, above about 2600rpm. If a 2-3 shift happens above that, it's a bit rough. It's a fast shift, that kicks you a bit, where it feels like the clutches are grabbing too quickly and not perfectly in sync with the engine."

This sounds exactly like mine, the way it behaves.

Throttle is just not >25%, neither is the rpm above 2600.

But the "issue" seems to be the same.

Have you done anything to correct this, apart from the things you have mentioned above in the thread?

 

No not at all. Yoda and Yamae are both vastly superior to me in experience and knowledge, so they know what's best. It's not a huge issue to me so I have never bothered to delve into figuring out if it's a problem or not.