Overdrive slipping when shifting down and then back up 2004 1st Gen

Hello-

I am new to this forum and have a lot to learn. I bought a 1st generation Tacoma (2004 4x4 extended cab TRD SR5 V6 auto) back in September (202K miles) of last year. Right now we are enjoying the truck as a second vehicle, but it will eventually be my 15-year-old son’s first vehicle. I am a single mom and wanted to get my son something I knew would be reliable. 1st generations speak for themselves. The only issue we seem to have is when we have to slow down from 5th/overdrive, then have to shift back up (it’s an auto but I mean when it auto shifts) there is a slight slip (in what I guess is the transmission)? Anyone else have these issues? Or know the cause?

It’s strange to me, because it doesn’t do it unless we have to slow down and shift back up.

Any help would be great.

Thanks in advance.

 

To me that sounds like the torque converter is unlocking and then relocking. That actually sounds normal to me, but I haven't driven an automatic tacoma.

 

That sounds "better" than bad transmission...I will check into torque converter. Thank you so much.

 

Sounds like it maybe it for some fresh fluid. They have a steel mesh filter that can be cleaned, and use Toyota fluid only.
Search for a regional thread near your area and ask for a reputable shop.

 

When you slow down, are you just letting off the gas, or pressing on the brake? I *think* it should stay locked when just letting off the gas, but it would unlock pressing on the brake. Hopefully someone else can confirm this.

 

It happens when letting off the gas and then accelerating again. I will check into that as well Catcrazed. Thank you for the info! This is all very helpful.

 

The whole front end jerks and doesn't feel normal to me at all.

 

I would start with a fluid change...don't do a flush unless you know the fluid has been changed regularly in the past, but given the symptoms I'm guessing it hasn't been...so a 'flush' could ruin it. But a simple drain/fill with new fluid could help it out.

 

?, I don't think she's complaining about it not running like a race car.

No it's not normal. It also doesn't stay engaged while you let off.

i agree it's probably the lock up hanging up. You really shouldn't feel it doing anything funny except right at 45mph where the minimum speed is for it.

Try a good transmission drain and refill and maybe even a couple of times each oil change. hope for the best.
On the dipstick is the type of fluid minimum it takes. Buy from a parts store or WallyWorld, Toyota fluids are actually crap IMO.

 

@eon_blue thank you, yes i've heard not to do a flush (so that's good to know) unfortunately, buying used i am not sure about how good they were about keeping the fluids changed. i know the timing belt etc. was up to date. i will try the drain/fill. i've actually read that a lot when researching this issue.
@Jamesboy2233 it does feel a little like you're describing just worse at times than other (i cannot figure why)? strange to me...

 

It's a better fluid than what you buy at Toyo. IMO. and cheaper for multiple flushing.

I would bet with some deep cleaning (from underneath) you can buy a lot of life on the transmission but I know not everyone is comfortable pulling the valve body down and cleaning it. That's where almost all the gunk collects and gets stuck though.

If you know a guy with a trans. shop they could knock it out for you quickly but it has to someone you trust. The chain shops are horrible. Private owned and willing/ wanting to make a cutomer for the long run is what it takes to get helpon these things.

Or someone who is a hobbyist. You don't have to put your address for location you know, side of a state is usually close enough.

 

no sorry. I was quoting you about Valvoline. You have your town.

 

I am in middle Georgia, small town of Eatonton.

 

honestly, i haven't thought about if i have touched the break or not (i just know it's when i have to slow down and accelerate again). i will make sure to be more attentive to that. it may be the difference in why it's worse at times.

 

Look in regional forums for people local.

 

how much are you slowing down? from what speed to what speed?

how loud is the "noise" when it shakes? thud/thunk, or ping noise?


also these are electronically controlled "lock-up" torque converter so there is no 5th gear. We have L-2-D (O/D) so 4-speed trans.

What I've done is when I need to "shift" is press the O/D button to disengage the O/D for a quicker response. then when I'm almost back up to speed press the button again and let it get to O/D

unless you are on a completely flat road your TC (torque converter) will "unlock" to allow the engine to rev and help move the truck more, not enough to down-shift but allow it to speed up.

 

@frizzman you're correct... if I'm on a flat road I am not experiencing this issue (or not yet).

I apologize I said "5th gear" I just immediately think of 5th as overdrive-not an excuse, but I am a female and haven't really had to work on vehicles. The very reason I am asking on this forum.

This may explain better-I did try taking the O/D off and still felt the "pull" still, but not as much of a "thud/pull" like feeling when O/D is not on. It is happening when I slow down to maybe 50 and then accelerate to 60+. It is for sure happening when climbing hills. It feels almost as if it doesn't have the power, but then "turns over" with a "thud." It also doesn't happen every single time, but more times than not.

I hope I have explained it well. I thought of trying to take a video and uploading it.

 

Lock up hanging is one of the number one things that people first notice about a dirty trans.
Sluggish pressure signals though the valves or solenoids whichever the case is.

It needs a good cleaning out to get the best life out of it that's left.

It may still go a long time if clean. Dirt and heat kill them.

I always rec'd ANY auto. trans. to have a cooler installed. I know they prolong the life of them esp. in the south where it's hot.

 

That is great to know. Thank you kindly.

 

Look for a privately run trans. shop and meet the owner/mech. (usually the same guy in the small ones) tell him what's going on and ask if he rec's a good cleaning. He may have a diff. take than me so that's not the point. What you want is a good relationship with a mech.

If he starts talking about rebuilds and the like without even looking inside, go somewhere else.

I've had Toyo. trans. look like total **** on the dipstick, act sluggish during shifting and got lots of life out of them after a good cleaning. It was however time consuming to do underneath so it's not under 100 bux.

If a pan gets dropped though and there is ground up metal....like chunks.....you have a problem. Something broke. It will have to come apart.