mt_goat

Scary topic for me (2001 Tacoma auto tranny here), subscribed.

MadCityRich

I'd be interested to know the issues surrounding OD gear failures. While I'm not in the camp that thinks there is a problem, I do wonder if there is something to how people drive and where they drive.

First off, I'm not even sure what rear axle ratio I've got. I've looked at the tables and it still seems to be either a 4:10 or 4:30. This is for a 2002 Ltd model. Where I'm going with this is that I think the tranny tends to try to hold OD for too long when struggling up steeper hills on the highway. I run stretches of highway that have rolling hills with some pretty steep climbs. I've taken to attempting to force an upshift early, or dropping the tranny out of OD.

Could there be any merit to the idea of lugging the transmission in OD? This would be similar to lugging an engine - running it at too high a load for the rpm. When an engine is lugging it tends to put more stress on bearings. I don't know enough about auto trannies to understand the issues, but maybe someone here does.

MadCityRich
2002 4Runner Ltd.

mkgarrison5

those trannies first off are dexIII trannys which we all know is a sub par atf fluid by ALL means.. if you are running a basic dex3 atf i would deff switch to a synthetic version first off. if you dont want a syn then do your drain and fills every 10k miles. dex3 gets burned out very quickly..

this is the one thing we dont know, how are they treating their trannys?? they could be from people who neglect them and do not maintain their trannys.

thats why i emphasize how important it is to do frequent drain and fills esp with dex3 trannys. its more important than the motor oil you use in these easy on oil motors..

Greg_Canada

my 99' sticks too in 2nd gear when its cold outside, it only does it for the first shift and i believe it's just because its cold. hell in my 89' i leave it in 2nd for awhile to let everything warm up, because there is very little load on the engine.

It helps it warm up faster. I always drive it slowly when its cold.

mkgarrison5

you dont even have to leave it in second in order for it to warm up faster. just drive normally but drive slower. the key is not to let the rpms get up high (above 3k if you can help it) until your truck is at operating temp.. so drive normal and or slow till it warms up..

Skrillah

The "sticking" is normal-its just the tranny warming up. No biggy.

As for the tranny problem, it seems to affect the A340F transmissions. You can find this information on the door jam of your vehicle. Here is an excellent thread to read through to get more info, and it contains pictures of the damage. Per this thread, it does affect the tacomas as well...:

https://www.yotatech.com/forums/f2/p...images-111443/

It appears that its just luck of the draw...some see the problem...some don't. If it were me and I had one of these trannies...I'd be putting a tranny cooler on asap along with just draining the fluid regularly not flushing. Whether that would actually help...I don't know...but I'd bet it'd make me feel a lot better! Haha...

MadCityRich

Keep in mind that the above post relates to a 4Runner with a supercharger. The thread also explains that the valve body upgrade may have prevented this problem. My point is that the experience of this specific tranny is not generalizable across non-supercharged trannies. If we are really going to get to the root of the problem we need to be clear on all the variables.

I do wonder if the power of the supercharger may be akin to lugging the tranmission in OD - too much power delivery at too low an rpm.

Is it possible to lug a transmission?

MadCityRich
2002 4Runner

INKMAN411

Tranny fluid is dexIII by Pennzoil. I flushed the tranny with a t-tech machine at my shop. This truck did not fit the normal ( highmileage, fried fluid, abused vehicle) criteria that normally would raise any flags which is why I'am a little bummed to say the least. I have put in some lucas tranny additive and that really didnt help which suprised me.

I have only had my 4runner since the beginning of Nov. and went over it quite thoroughly prior to buying.It had 53555mi on to odometer. Prior maintenance records were unavailable. Mine has the a3040le, but on the door sticker indicates an a340f. Go figure.

Speedy

Sticking in 2nd gear when cold is 100% normal. Mine's done that since I got it with 12K miles on it.

naksukow

I don't know about your buddy but John from IPT performance transmissions told me the 01-02 4runners have a weak planetary gear. And it is a known problem.

mkgarrison5

first off switch to a synthetic form of DEXIII (amsoil or M1 preferably). you will see a major difference..
second anything lucas doesnt really work that well, do the research.

try that first and let us know.. btw the color of tranny fluid does NOT indicate (unless brown or black) whether or not your atf is shot or not.

mkgarrison5

so you are saying that ALL of these issues are from runners that are SC'd?

MadCityRich

Nope. You misunderstand me. I'm not saying there's not a problem. I just don't see the clear trend. I like data, not anecdotes. Anecdotes can be informative, but can also be a biased sample.

What I'm wondering about is whether delivering power at too low an rpm might be the cause of planetary gear failure. The fact that it's the OD gear that seems to be an issue could be due to design of the gear itself, something related to "lugging" the transmission, or a combination.

Let's take a non-SC 4Runner. Let's say I've got 4.10 gears. If I'm climbing a hill and the transmission doesn't downshift until rpms get to a very low point, could that cause damage? I don't know. I'm asking the question. But the issue is one of too low an rpm for the power delivery of the OD gear. If I have 4.30 gears, am I less likely to experience planetary gear failure because my tranny downshifts sooner than the 4:10, keeping the tranny delivering power at a higher rpm?

I'm just raising the question. If people want to take offense at questions, that's fine. But on the Tundra forum and others, it appears that there are many '01 & '02 auto trannies that have no issues and last many many years. What I'd like to focus on is the cause of the failures, not whether there have been failures.

Maybe it was a single factory worker who did a really bad job on his line. Maybe it was the undersized washer I've heard about. Maybe it's maintenance habits. Maybe it's driving style. Maybe it's gearing. Maybe it's just that we tend to hear about problem vehicles on Internet forums. I don't have a dog in this fight - I just want the data. OK?

I also know that it's nearly impossible to create reasonable databases of information on Internet forums. Someone's truthiness ox gets gored and the debate devolves. How many planetary gear failures have been experienced in the '01 and '02 4Runners? How does that compare to other years of Toyotas? How does that compare to other manufacturers? We can't say there's an unusual problem until we have a comparison. If someone has this data, please share it. If not, let's talk about root causes since we know many of these transmissions last with typical Toyota reliability.

MadCityRich

mkgarrison5

Mad city, well if you are offroading you shouldnt have the damn thing in OD anyway, its strictly for highway use imo. lol but i get where you are coming from and i think this issue should be researched more

xcmountain80

Oh you'll love this. I only just noticed the hanging in 2nd when cold and I have 195K on mine. I swapped gears over a year aog which was my 1st thought when INKMAN said his was doing it. I had amsoil tranny fluid added at 100k so its probably time as I was under the impression once amsoil in you didnt need to do it again. I have a cooler and don't regularly drive like a tool. So for good measure I'll swap the fluid just because and go from there. B4 I refer to the manual how much fluid and which Amsoil Syn?

Aaron

ARB1977

How do i know if i have the same tranny? Does the Taco and Runner have the same transmission? My 02 Taco has been doing this since the day i bought her. First thing in the mornings when it hits second it will hold it for short period then shift. Once its warmed up shifts normal. If im not mistaking i though the book says it does this. It speeds up the process in warming up the cats. 92K miles and no other issues.

xcmountain80

Yea from what I've been reading this is normal and sleep should not be lost over it. If I'm wrong please correct me. The weird thing was in the 130k that I've had the truck I only started noticing it more recently.

Aaron

Speedy

Totally normal. My 02 4Runner has done the same thing since day one, before I SC'd it, as well as after. It's normal and is actually part of the warm up cycle.

mkgarrison5

you used lucas tranny additive??? WHY????? if anything they do more harm that good.. the additives in that may "collide" with additives in the ATF... never use an additive man

mt_goat

I thought this thread was about this: https://www.yotatech.com/forums/f2/p...images-111443/