Transmission

I’m new here and also a first time Toyota owner. I am a knowledgeable backyard mechanic so I know my way around trucks pretty well. BUT the extent of my knowledge of transmissions is limited to changing fluid and gaskets and filters and how a transmission works. Having said this I just purchased a 2007 Toyota Tundra 5.7 ltr CrewMax TRD 2wheel drive from a friend. He deals real estate for millionaires around the country so it’s has interstate miles on it and in immaculate condition. Miles are 331,000 miles on it. Transmission fluid has never been changed . It is delayed in shifting in reverse and 4th and 5th gear sometimes will not shift . Also slips in low gears sometimes. I noticed a leak near the trans but haven’t looked hard for it yet ( JUST purchased it ). I opened the fluid level plug to check level on the pan while it was running and hot and made sure truck was level when doing this and it blew out about a 1/4 qrt of BLACK trans fluid . I let it run for 5 minutes with plug out and then placed plug back in. It still has a delay at random in reverse gear. My question is SHOULD I gradually change out the fluid ? Say drain the pan and add whatever I take out and do it again the following month or just change it all out at once BUT DO NOT FLUSH THE SYSTEM OR BLOW IT OUT !!! Just drain and fill . Or are the interstate miles to high and I may just mess up the trans ?

 

You probably lowered the level since the level is supposed to be checked at a specific temperature ~115F at the pan.

Yes definitely change the fluid. You don't want to power flush it, the easiest way is a drain and fill, though you can also disconnect the lines going to the trans cooler and have it pump out the fluid and refill it at the same time so you get all new fluid in one go, but most people don't do that.

Drain pan, refill pan, monitor the trans temp with an OBD2 scanner and when the temperature hits 115F then pop the level plug.

 

This 100%. The truck is low on fluid so you need to top that off, first thing. Sounds like a good excuse to do a drain and fill

 

Black ATF is not a good sign. I would do a few drain and fills using the correct procedure to check fluid level. Dropping the pan is not generally recommended since the “filter” is more of a strainer. Also the pan bolts are subject to corrosion and snapping when removing if not careful.

 

If it's already slipping and not grabbing gears there's a small chance fluid change will help. Usually the grit in the old fluid is the only thing giving those clutches friction. Might be too late. Maybe use the cheapest WS fluid you can find for now to see if it even helps.

 

+1

330k is simply too much to ask from your trans fluid. Absolutely no surprise that it is failing. Certainly worth the effort to change fluid, but suspect there is now too much clutch wear from lack of fluid additives. The black color is is all of the worn off clutch material being held in suspension.

I just don’t understand how people will religiously change engines oil, but abuse a trans like this. Sorry, but ther is no such thing as lifetime fluid, unless your view of lifetime is 100000 miles, like Toyotas view.

 

Because it's not simple to fill. That means most people will take it to 'the guy' and let him do it. People aren't all that great about saying "I've reached 100k miles, lets get it into the shop and do all the things it needs" nor do they like paying for it. Radiator fluid is another thing that get's ignored. I can't remember anyone ever changing the brake fluid due to age. Obviously in a perfect world people would do all the maintenance.

When I was much younger I worked at a glass company. We had a GMC 3/4 ton that never had the oil changed. After about 10k miles on the oil it would just get topped off on occasion. After about 75k of this the owner's son decided that he would do it. The oil was so black and nasty that it stained his hands. It took weeks before it wore off his hands. It wasn't that much longer before the engine spun a bearing.

 

I was thinking the same thing myself. I will do this tomorrow. I’m “ worried “ it may be too late. But if I have to buy a new one then so be it . But like everyone else I would rather spend $3,000 on extras for the truck . Worse case decision would be to buy a factory remanufactured or brand new. I will let everyone know how things go. By the way I saw one video where the guy put a “ grenade pin “ in the trans thermostat to hold it open . Should that be done when drain and fill tomorrow?

 

Look up the drain and fill procedure or transmission level check procedure. It’s pretty straightforward but there are a few steps to follow when checking the level correctly. But, yes, if you have a transmission cooler, you need to pin open the thermostat when checking the fluid level.

 

$3,000 seems optimistic. If you get a unit from Toyota I’d expect it to cost 2x that by the time you are done. Given the multiple issues - not sure id throw money at the old one.

 

Depending on the shop, a reman might come in around 3k. One of the guys over on the supercharged thread is having their transmission replaced at the dealer for $3600 OTD for parts and labor. Off hand, I don’t remember exactly who - there are too many guys burning down transmission over there…

 

You can pin your thermostat. Especially if you see temps above 200deg. Toyota WS fluid is supposed to have a sweet spot at 190 deg for longevity. A lot of us are shooting for 170-190deg or even a little cooler but that may seem controversial to some and changing fluid every 30k.