skyther

Hi guys,

Hopefully someone will be able to give me a hand with my tranny issues. I have an Aus delivered UCF10 that I've owned for about 6 months now. Over the last few months, the car seems to have been exhibiting the following issues:

- rather bad vibration while in D, but not P/N
idle drops from 650 to 600 when placed in D
cleaning the IACV and T/B did not help vibrations
adjusting TPS to factory specs did not help either
- occasional jerk when shifting from P/N to D
- rough and erratic engaging, especially when slowing down or maintaining a low speed
most noticeable when going through a roundabout or driving in a parking lot
ie. if you slow down (but not to a complete stop) and accelerate again the car hesitates for a second and then engages

I then tried adjusting the tranny throttle/line pressure cable to see if I could get the tranny to shift smoothly, and the following issues started appearing:

- rough shifting between gears, especially from 1 - 2 where the car feels like it hesitates for a second before changing
- when slowing to a stop from driving speeds, the car would jerk when downshifting
- there was an occasional squeal from the transmission when reversing under load (up an incline)

- about a month ago, a loud "ticking" (on close listening it sounds like those music shaker thingys) sound started coming from under the car when cold, pretty sure it wasn't an exhaust leak
the ticking is present while in P/N/D/R, and gets louder/more frequent with increasing revs
ticking would stop when the car warmed up
- no diag error codes shown

I spoke to the last owner and was told that he had flushed the tranny with a "suitable for T-IV" fluid (Penrite MHP) about 6 months prior to selling the car. The fluid was by now turning slightly brownish. I purchased a barrel (20 litres) of Mobil 3309 (which AFAIK *is* T-IV) and did several drain and refills to clean the old oil out, which took about 11 litres. The ticking stopped after this. I proceeded to do several drain and refills over the following 2 weeks till the 20 litres were completely used up. At this point I was about to look into getting replacement tranny mounts to see if they would fix the idle vibration issue.

A week ago, the ticking came back, followed by a loud grinding noise as well as a whine that can be heard in the cabin. The noise seems to remain even when the car is warmed up. Does it sound like my torque converter is toast?

Thanks in advance!

Lexozz

This is the key. Should not have flushed it and then use aftermarket tranny fluid.
It's gone bro, time for a replacement or rebuild. I am suprised its still moving.

PureDrifter

iTrader: (10)

mobil 3309= Toyota T-IV.

are you sure the grinding is coming from the transmission?

skyther

Thanks for the replies!

The ticking/grinding is loudest when heard from under the car, behind the front wheels. It's not as loud when listened to from the engine bay. There isn't a blowing sound either so I'm sure it's not an exhaust or EGR leak.

The noise was especially bad yesterday morning when I took it for a short drive, and there were 2 occasions where it would rev to 3k before changing to 2nd when accelerating (lightly) from a standstill.

hypervish

It may be helpful if you can take a video.

Thermactor

iTrader: (1)

Clogged transmission filters have made the difference in two A340 transmissions between operational and non-operational. I can't recommend changing the filter highly enough. I tossed an Aus-made Magnefine filter on my trans cooler lines for extra filtration.

skyther

Hello!

Turns out the transmission filter was clogged up and caused fluid pressure to drop. I had another fluid change done, filter swapped and a new torque converter installed.

However, the car still does not shift smoothly. It's not as bad as before, but there is still a slight but noticeable jerk shifting from 1 to 2, and a less pronounced jerk going from 2 to 3. I have been adjusting the transmission throttle cable in an attempt to smoothen out the shifts. The workshop I took the car to also overfilled the transmission by quite a significant amount - I've drained some fluid out so it's at a the correct level. It shifts a little better now, to the point where I wouldn't call it a jerk, but there is still a noticable "drop" in acceleration as it jumps between gears. The jerkiness seems to vary significantly with small adjustments to the throttle cable, say a 15 degree turn of the nut. Is this normal?

As before, it also jerks when downshifting / slowing down to a stop. This is very pronounced when the car is still cold. The transmission mounts have been changed. I've also adjusted the TPS with a Fluke DMM to ensure that it's set correctly.

Another strange issue is when checking error codes, the ECU is reporting an error 47 (sub-TPS error). My car does not have TRAC and hence only has one TPS.

Does anyone have any suggestions? Thanks!

python

iTrader: (4)

mounts maybe,also try adjusting the cable the other way a little and see if it helps or gets worse...lexozz its not a good idea to tell people their trans is toast. always remember to take ur transmission problems to a tranny shop not a repair shop!

skyther

Engine mounts? I did change the tranny mount and it hasn't made difference at all. Adjusting the throttle cable either way seems to cause it to slam into gear.

Also, the car is still vibrating in drive at idle, as mentioned in the first post. Tacho is showing 600 RPM when the vibration starts. I cleaned the throttle body, vanes in the MAF (with isopropyl alcohol, didn't touch the mirror) and ran seafoam through the engine and fed new oil but it didn't help. When cold, the vibration can be quite severe; to the point where it feels like I'm sitting in an old diesel bus.

The engine mounts are quite pricey so I'm not sure if I should fork out for them since the transmission mount didn't do anything.

Bradster

How many miles on the vehicle? My original motor mounts showed quite a bit of wear not from abuse but the heat and weather cycles in NY over the years...nice and smooth after the switch..1990 LS400 with 230K miles when replaced in 2003 i believe...

skyther

It currently has 270000kms on the clock, so just under 170k miles.

I did a little more searching and it seems that my issues may be linked to the TPS. I did try a different TPS a while back which didn't make much of a difference, although this was off a different car (mid 90s Camry V6) and was Aisin branded as opposed to the Toyota branded one I currently have.

I'm not sure if my TPS is faulty as the IDL-E2 reading seems to drift a little depending on how I release the throttle, ie. gently or let it slam close via spring action. Also, the throttle lever appears to turn several degrees (ie. shaft play?) before the butterfly valve actually opens, so I can't adjust the TPS using the feeler gauge method as inserting the gauge between the lever and stop screw doesn't actually move the valve and hence the TPS does not register a change. I could be wrong, but it appears that this design is intentional on the RHD models. Do the LHD models exhibit the same "shaft play" on the throttle lever?

Also, the IDL-E2 readings for my current TPS scales up from about 5 Ohms fully counter clockwise to around 250 Ohms, before losing continuity altogether. If you make very very slight adjustments between 250 Ohms and infinity you can get a reading of about 1.3K Ohms. The Aisin TPS I tested however, maintains very low resistance up till a certain point where it loses continuity altogether. Is this normal?

GeoIII

Hello,

My name is George and I problem Im having with my 93 Ls400 is the car will not pull any gears! about a few months before I was experiencing some winding noise from the engine but then it would go away. then sometimes when I would shift out of P to R it would shift really hard! Now the car wont go into any gear what so ever. when I first start it up it will but when it warms up it wont. can you tell me what the problem is.. thanks George

skyther

Hi George, check your transmission fluid and make sure it's not low / brown / burnt. There's also a good chance your filter was clogged like mine was.

skyther

Just to provide an update to my jerky shifting issue...

Got a Denso TPS from an import junkyard, didn't fix the problem but the my Fluke DMM shows that the resistance on this one doesn't jump around as much as my original one did. Wrecker was a nice bloke though and seemed to know his stuff. When I asked for a TPS he took a glance at my car and went "Oh a LS400... what do you need a TPS for, are you having gearbox issues?" He told me that it could also be an issue with the solenoids.

I then spent a good 3 hours on the car installing a new exhaust gasket and cleaning the tranny solenoids and doing another drain + refill. I soaked all 4 solenoids in parts cleaner for a good half hour and then tested them - all seemed to work fine. For good measure I also added a bottle of Lucas Transmission Fix as it claims to stop hard shifting and also seems to have worked for a number of others. Not that my tranny was slipping or anything; I could do a standstill burnout with a 1900 RPM stall just by mashing the throttle in. The Lucas stuff is extremely thick so I mixed it with 2 litres of T-IV in a bottle to let it go down the transmission dipstick a little easier. It shifted nice and smooth initially, but after topping the fluid up so that it was at 3/4 of the hot marking on the dipstick it started to jerk again. Even more strange was the fact that I could feel my TC locking up whereas it was so smooth you couldn't notice it before.

Then I suddenly had an epiphany. I had a look at the throttle opener attached to the throttle body and realized that the reason as to why I had that play in the throttle shaft was because the opener was keeping the throttle butterfly open all this while, and hence my TPS was incorrectly adjusted! I removed the bracket holding the opener and dash pot and readjusted the TPS. The car now seems to behave a lot better, especially during a cold start. It still jerks a tiny bit on shifts but it's much more consistent. I may have to play around with the transmission cable a little as the Lucas has increased the line pressure by quite a bit.

expansive

wow i have to say this is a very nice thread. Im so glad i found it because my car is giving me the EXACT same symptoms.

Thank you so much for creating this thread, Skyther. I wish you lived near me because i would pay you to do this to my SC400.

I just have to try to do some of this myself