Is this a companion flange? Potential Leak

When under my 2005 2WD DC today, I noticed a small leak at the union of the drive shaft to the transmission. I don't know what this is called. Might you know what the leak is coming from? Thanks.

 

Transmission output shaft seal is what you'd be looking to replace.

The driveshaft has a slip yoke that both slides onto the transmission output shaft and into the output seal.

 

I picked up my 2005 2WD DC in February with 132,000 miles at the time as its second owner. I picked it up from a dealership when the original owner traded it in on a 3rd gen Tundra.

There isn't a lot of service history from Toyota.com or Carfax.com, hence I have made many of the recommended improvements suggested in this forum (drive belt, idler pulley, water pump, timing belt, radiator hoses, etc.)

I want to get some serious life out of this truck, but I am now questioning whether or not I should have the transmission fluid changed. I have a little seepage at the transmission output shaft. The local transmission shop said that I am better to leave it as is. His advice seems to be the opinion of many on the Web.

Should I have the transmission fluid changed? The previous owner took really good care of the truck so part of me thinks that the transmission fluid was changed in the past.

 

You could always pick up 3-4 qts and do one drain and fill to check the condition of the current fluid.


I did 12 qts at about 168k. (4 toyota ws and 8 of the Valvoline Maxlife)

 

I’ve heard redline is a decent fluid as well, I just stuck some in my rear diff.

 

Dunno about their ATF but their gear oil is pretty good. Just skip it for clutch type LSD (OEM/TRD). For those use Motul 90pa instead.

 

I didn’t know the Oem lsd used a different fluid

 

Clutch type LSD's work best with conventional oil with the proper friction modifier added to it. The Motul 90pa has the proper amount already included so you don't have to buy it separately.

 

I believe (I have and 04, so I don't "know") the 05 has the "sealed" transmission. Only use OEM fluid (which I believe to be WS)

 

You are right on the money. My 05 has the sealed transmission. The reputable transmission shop down the street was really cool however suggested leaving well enough alone given the 136,000 miles that are now on the odometer. He told me that the detergents in the new ATFs will break down the varnish that has formed over the years which could result in damage to the internals and could cause slippage.

I have plans to keep this truck for 20 years or more. My issue now is more philosophical. Do I follow his advice and hope for another 100,000 miles with the original ATF before the transmissions dies a natural death or try to change out the ATF fluid in the hopes of getting 300,000 or miles on this transmission.

 

Varnish shouldn't be what's holding the transmission together. Doing a drain and fill (still possible with the sealed transmission, all transmissions are sealed BTW, this one just doesn't have a dipstick to check the fluid and fill) will still provide you with some fresh oil, usually 3-4 qts, and detergents to keep harmful buildup from forming. Flushing is generally discouraged on high mileage units as to prevent dislodging debris that could clog valve bodies and passageways. When I bought my truck with 100k miles on it, I did a drain and fill and changed the transmission filter (older model 4 speed trans) and have done a few drain and fills since then. At 260k+ miles, trans still works great. Now that's an N of one for the scientific folks at home, just my experience.

 

That's a commonly shared story, but it's not fully clear whether it's an urban legend or scare tactic to avoid liability. We talked about it a bit starting on reply 21 over here recently: https://www.tundras.com/threads/1st-gen-high-mileage.58047/#post-2405781

Is it valid? Maybe for some vehicles, in some conditions. But any issues it'd expose would speak to other underlying stuff than the actual risk of the maintenance process. It's important to understand, people often show up at transmission shops when they start to sense problems, and the work they may perform, like flushing the entire system, would just help to exacerbate or further highlight the problem, not cause it. I think that's where the confusion comes in.

Like, I feel it's the same way a deep-root scaling at the dentist to remove plaque from years of dental abuse/neglect can actually expose another issue, or even lead to a failure because the plaque - which would ultimately lead to failure anyway - was helping mask a pre-existing issue. But at the end of the day, if there was no obvious plaque and no evidence or concern of previous failure or abuse, it shouldn't result in problems.

Does it mean you should never get a deep root scaling? No. It's a pretty invasive process though, so if you can get by with a more gentle, multi-step process that would gradually clean out the funk - which isn't necessarily something a transmission shop can afford, a 3-trip visit getting you into a bay - then the multi-step process is the best bet to avoid possible risk, or to be highlighted of a larger problem during one of your early steps.

 

136K miles is not a lot for an Aisin transmission -- this isn't a Chevy.

Drain the pan, measure what came out (should be 3-4 quarts), and put exactly the same amount back in the fill hole. Do that at the next several engine oil change intervals and you'll be good to go!

 

For those interested, here is how the story unfolded. I checked in with NAPA and Advance Auto Parts and neither carried Toyota ATF WS. First learning. I purchased 12 quarts from the local Toyota dealership which was 9 quarts too much. Second learning. I took it to a local shop who drained 3 quarts and added 3 quarts. I was a little miffed that only 3 quarts were replaced but that seems to be the recommended amount. The filter was left alone. The truck was shifting fine before and is still shifting fine. I need to get a few extra tools and maybe a buddy if I am going to fill the sealed transmission at home. I have seen one guy do so on YouTube and it looks tricky. I think that the old transmission fluid didn't appear to be extra dark.

Here's my big takeaway. I talked with a local independent shop who suggested leaving the transmission as is. I called the dealership out of curiosity and he said not to do so because the sealed transmission is good for the life of vehicle.

I am glad that I went with my gut and with the advice from this forum. Thanks to all.

 

Appreciate the follow-up. The fluid does look a little dark, but I prefer to water-paint it onto some white card stock to get a real key on how it is.