Brokenrunner

Hi.
I have been having a strange shifting issue with my 1994 4runner v6 4wd automatic.

It had a leaky valve cover so a friend and I decided to replace it. We removed the upper intake manifold, throttle body and some hoses to get down there to replace the gasket on the valve cover. We replaced the gasket on the intake manifold as well then we put everything back and i drove it home.

The next day I noticed it jerked kinda hard when shifting in to reverse from park and that the idle was a little high. It also jerked a little when shifting from 1st to 2nd. Changed a few old hoses since we thought the high idle was causing it and it seemed to improve a bit and we left it alone.

I tried to drive it on the interstate and it started ok but once it hit about 50-60 it was struggling to keep up. Sometimes id have the pedal all the way down and it would start slowing down and revving a little high. After a few more miles of that the A/T oil temp light came on and we had to pull over to let it cool down. After that the shifting was much harder and it jerked more. Drove it again this morning and it was shifting much harder and jerking out of 1st hard but shifting normally after 2nd until i had to stop and shift out of 1st again. At one point it jerked hard and the check engine light came on for a split second. Please help! Thanks again in advance

85gijunk4x4

I THINK (don't quote me) that the a340h has some kind of vacuum into the intake manifold. Unless im thinking of something else. Deffinatly look into that though, maybe something got crossed.


Sounds to me like you have un-related and coincidental transmission issues. Just my personal oppinion

Brokenrunner

Thanks for the fast reply! Its been driving me insane, Fix one thing break another seems to be my pattern. Ill look in to that vacuum

scope103

Start by checking the throttle cable.
http://personal.utulsa.edu/~nathan-b...32prelimin.pdf

The shifting points are determined by the TPS, ECT and the ECU. But how hard it shifts is determined by the throttle cable. If yours is essed up it could be shifting "hard" all the time.

PS: there is no vacuum connection to the transmission.

Brokenrunner

I originally thought it was the tps since it almost feels like its not shifting in to O/D. Didnt want to dig right in and break something else in the process of guessing at it. Ill check the throttle cable.

Brokenrunner

Unfortunately it looks like a storm is rolling in so I wont be able to work on it today. I'm still open to any ideas though. Thanks

Brokenrunner

Ok. I adjusted the throttle cable and kickdown cable and the it doesnt jerk when shifting in to gear and was able to shift in to O/D.

However, after testing it out on the highway going about 60-65 the car slows down and decelerates with the pedal to the floor going slightly up hill and after a while the A/T oil temp light comes back on.

After letting it cool down the light turns off and doesn't come back on until we hit more slight inclines.

crash813

Adjust the throttle cable. This is different from the accelerator cable. This is what sets the line pressure for the transmission. Relax it off a bit and the shifting, especially out of park, will be much gentler.

Brokenrunner

Would this help the issue when going up small hills on the highway and A/T oil temp light coming on?

crash813

Well, I'm definitely not an auto tranny expert but I have found these things are very picky especially in regards to O/D. If the line pressure is too high at idle, I'm sure it will effect it throughout the range. Plus, this tends to be one of the gotcha's that most people go through when removing the intake for the first time. I would just back it off for now and see if it helps. Hopefully nothing burnt up but you might want to take a look at the fluid and make sure it still looks healthy.

Brokenrunner

Ill check it all out and post back. Thanks

Brokenrunner

It shifts much better now that the cables have been adjusted.

Still slows down going over small hills over 60 with the gas pedal down. A/T oil temp light comes back on after awhile of it struggling uphill even if they aren't steep.

scope103

You don't have a "kickdown" cable. Back in the day ('70s) a throttle cable connected to the transmission set the shift points, so when you pressed the accelerator that cable would cause the transmission to down-shift ("kickdown"). On the A340H that downshift is commanded by the ECU using the TPS to determine accelerator position.

You have a cable to the accelerator pedal, a cable to the transmission, and assuming you have cruise, a third cable for that. Yeah, all three have to be adjusted properly, but the shift shock you had was (most likely) caused by a mis-adjustment of the throttle cable to the transmission.

Brokenrunner

Ah ok. This is why I like this site. I don't know enough about my poor 4runner.

I adjusted the two cables that weren't the cruise control cable.

scope103

Sounds like it is not going into lock-up. (If you labor the transmission through the torque converter, it will eventually over-heat the transmission.) But the "slows down going over small hills" sounds like an engine problem (which you are trying to overcome by holding the accelerator all the way down, which is forcing the transmission out of lock-up.)

Check for codes (both EFI and transmission, while you're at it), check ignition timing.

Brokenrunner

Will do! I'll keep posting updates. Thank you scope103

Brokenrunner

Could it possibly be a vacuum leak somewhere causing the engine issue uphill?

scope103

Sure. It could be lots of things. A vacuum leak will usually cause a lean condition, which will ... throw a code. So I would check first for stored codes.

Ignition timing off will not (usually) throw a code, it will just run poorly.

The key is to do your diagnostics more-or-less in order. Bad rings can cause an issue uphill, but no one would suggest a complete overhaul as a first step.

Brokenrunner

Update! tried to get a reading with a timing light but it looked like it was jumping around. Also noticed that my coolant is disappearing with no visible leak. Ended up swapping some vacuum hoses and replacing the distributor cap and rotors just because it was there and needed to be done.

Tried it out the next morning and it hesitated to shift out of first almost like a bad solenoid or a transmission slip but only for a second. Higher then normal rpm before it shifts out of 1st into second. Also found a hole in my muffler...lol

Any Ideas? could it all be one thing or multiple things going bad at once?