So noticed today for the first time - 2005 Sequoia w/ 130k miles. Forgive the question, I know almost nothing about slushboxes, having only ever owned them in SUVs, and never having anything ususual go on with them during my ownership. Anyhow:
First, when I was towing the rally car up a hill (in 4th with overdrive off, around 3000rpms), when adding power to maintain speed up the hill, started normally accelerating slowly, and then just for an instant the revs went up maybe 200-300 just for in instant and then dropped back down to normal. It did this 2-3 other times when I "tried" to make it do so.
Then, coming home NOT towing (left car/trailer at the track overnight), going back up the other side of the same hill I had to jump over a lane and accelerate hard to get into traffic flow. I pressed the gas down more, and it downshifted into 3rd as usual and started accelerating, and about a second after that again the revs went up maybe 200-300 again, just for an instant , and then back to normal as I accelerated hard up the hill.
Otherwise, the truck drove normally, and no slips when accelerating hard from a stoplight, for instance.
It didn't do this when I towed last weekend (same route) or ever before - at least not that I've noticed, can't say I usually watch the tach when driving an automatic - but I did change out the cracked header on the driver's side for an aftermarket one. IDK how this could affect the transmission, but just a data point. I also don't know if there's anything on that side of the engine that could have gotten disconnected/pinched as I had to kind of jam the old headers and motor mount in and out of there (not sure if any transmission-related stuff is near that area offhand.
Any thoughts before I start yet another project trying to troubleshoot issues with this increasingly annoying truck?
Sounds like it could be a torque converter momentarily unlocking. That would be worth a few hundred rpm increase. Why? I have no idea. Is there any Toyota software (similar to HP Tuners) that would let you monitor TC lockup?
Disclaimer: I also know very little about automatics so take that with a grain of salt. Hopefully Curtis or someone more knowledgeable will chime in.
Flaky TPS maybe? Possible connector to it or ground not great?
try a fluid change, looks like a fluid flush might work too. at least from what i see from google for that gen sequoia/tundra
Like Chaos said, I would change the fluid three times. Change, drive through the neighborhood making sure you go through all gears and change again, repeat.
I usually measure the fluid that comes out and replace the same amount.
Yeah, I've done two fluid changes in the past 20k miles or so. Super annoying on these since there's no filller or dipstick so you have to pump it up there, open an upper drain, bring the truck to a particular temperature, and then let it spill out until it stops. Thanks, Toyota, for making life more difficult for no freaking reason!
I'll plan to change the fluid next week and see how that does.
Do you have a good scanner? I used a Foxwell scanner to diagnose some transmission issues on our Odyssey. I also used Torque Plus to data log and document what was going on. I had two issues going on, my torque converter wasn't locking up on the highway with one transmission, and the second transmission was slipping. Lockup in OD (in my experience) drops the RPM by a few hundred.
The scanners were a huge help in tracking down both issues. They also gave me the ability to track transmission temperatures.
I agree with the fluid change recommendation, and I'd check torque converter lockup situation on your next tow. Logging temperatures can also be helpful to see if that's a factor. I wasn't towing, but I was surprised to see my highest transmission temps were actually idling, and not climbing up hills with the whole family.
dj06482 (Forum Supporter) said:
Do you have a good scanner? I used a Foxwell scanner to diagnose some transmission issues on our Odyssey. I also used Torque Plus to data log and document what was going on. I had two issues going on, my torque converter wasn't locking up on the highway with one transmission, and the second transmission was slipping. Lockup in OD (in my experience) drops the RPM by a few hundred.
The scanners were a huge help in tracking down both issues. They also gave me the ability to track transmission temperatures.
I agree with the fluid change recommendation, and I'd check torque converter lockup situation on your next tow. Logging temperatures can also be helpful to see if that's a factor. I wasn't towing, but I was surprised to see my highest transmission temps were actually idling, and not climbing up hills with the whole family.
yep, I have torque pro set up for trans and converter temp readings, so I'll keep an eye on it. Temps looked normal on my last tow.
