Please help me diagnose 07 LC jerking forward from a stop while trying to speed up....

[Francis K]

2007 LC with 215k on it, I bought this truck for my mom and completely baselined it plus timing belt/water pump, OEM pads and rotors all around plus other things. Since it came back from the shop I've been chasing down some other issues that my mom has encountered while driving it. I've had her stop driving it since until it can get it back in the shop as there is more than one issue but this was her description of one of the issues before that:

"When you stop or are stopping and you apply the gas to then accelerate the car jolts or jerks forward. I am uncertain if it is in the braking process or the accelerating process. Idk if it is the brakes sticking and releasing while you're trying to accelerate or a huge transmission slip. It happens very infrequently. Like 4 times in the last 4 weeks."


It needed new rotors and pads all around which I did so I was thinking maybe the calipers were sticking as it did kinda feel like that prior, but would a sticking caliper even create enough stopping power to keep the truck stopped and then jolt forward like that? I did a drain and fill on the tranny and the fluid looked great on it plus I know the trannys on these are pretty stout, no tranny issues prior to this whatsoever even before the baselining or any of the prior service records.


Anyone have any ideas as to what's going on here?

 

[rexington14]

She could just be feeling the driveline clunk when getting on the gas and mistaking it for something else. It's pretty common. Start with greasing the driveshafts U joints and slip yokes.

When you did the brakes did you also clean or replace the caliper sliding pins and grease them properly?

For transmission did you check the fluid level after getting it up to temp? If you just measured what came out and refilled it it's very possible the level wasn't correct to begin with.

 

[kpz1234]

Fuel filter?

 

[OEMGUY0720]

Bleed the brake lines, get one of those reverse brake line bleed tool which you can operate by yourself. From the information you shared I believe the brake system is the closest component related to the symptom, start from there and then eventually do a process of elimination.

 

[2001LC]

Sound like AT

Try this:
While idling in P. Press and hold brake pedal firmly. Shift into R then N then D the N then R. Keep repeating at least 5 times.
Does AT delay engaging.
Do you feel/hear a bang and feel as if vehicle lunges as AT engages?
Does it get worst the more you shift?

 

[Francis K]

Updating for the next donkey.....

@2001LC had it, it was a tranny issue. I did test it as he instructed and it tested fine but after taking it to my guy it turns out the hack shop my father took it to had left the tranny fluid two quarts low along with other things they botched. I'm hoping no permanent damage was done but she's running perfect now.....

Thank you again fellas

 

[2001LC]

Updating for the next donkey.....

@2001LC had it, it was a tranny issue. I did test it as he instructed and it tested fine but after taking it to my guy it turns out the hack shop my father took it to had left the tranny fluid two quarts low along with other things they botched. I'm hoping no permanent damage was done but she's running perfect now.....

Thank you again fellas

I too just had one yesterday. I did a 12qt flush, to make sure any mixes of ATF over the years and any insoluble like iron. Cleaned out. Shifts just fine now.

One issue, we have is valve body wear. The cleaner we keep fluid the better. 12 qt flush is best.

You've a 07. It's best to use Toyota WS ATF. Level must be set at 97f to 115f. Some are unaware of the TSB that reduce to this temp. Best set at at lower end of A/T #1 temp of 97F. More fluid the better.

Another issue we're see. Is ATF fluid in A/T case wire housing blocks.

Thread 'Alert, Alert, Alert----- Transmission valve body wire housing block! --- Have you looked into yours? Capillary action drawing ATF in!'

Nov 23, 2025

This automatics transmission's (A/T), wire housing block on driver side (LH) of A/T. Which connects to solenoids & temp sensor(s) within A/T case on valve body. Is heavily coated inside with a gray/green GOO. What is this GOO?

Any guesses what thick appearing oil substance is?

Anyone have pictures or can comment on theirs, they care to share here?

Edited 12/14/25:

As you read through this thread. It will become apparent we've ATF capillary actuation issues with: Transmission wire, that come out of A/T case from inside transmission. It's the wire housing, that connects all valve body...

• 2001LC
• Replies: 62
• Forum: 100-Series Cruisers