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Discussion Starter · #1 ·
I have an 07 LE with just about 200k miles on it.

I think my transmission is starting to slip a little. When starting from a stop or at very low speeds, it seems like every once in a while the RPM goes up but the speed doesn't, as if the transmission does not want to shift. It goes away very quickly when I feather the gas pedal.

My search says the most common cause of slipping trans is low trans fluid. I checked while it was warm, with the engine running, and it was about an inch lower than the upper(hot) range on the dipstick. I topped up but it didn't need very much to return to the right range.

So I'm thinking maybe I can add some of the stop slip stuff as well. Does anyone have experience with this? My trans fluid level is normal now so I'm not sure if adding this will have me end up with an overfilled fluid level, or if it's meant to be used like that. Or more importantly, if it's even worth using at all.
 

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If it’s already slipping, there’s little to lose. A bottle of Lucas transmission fix is 24oz. If you’re pouring in the whole bottle, you might drain or vacuum out that much.

Sixto
‘04 LE FWD 203K miles
 

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Sounds like a fluid and filter problem to me. If you have changed fluid and filter, and have the T-IV or WS fluid (dependent on what's spec'd for that year). If your transmission dipstick is black on top and has "ws" marked on it you need toyota's World Standard fluid. It it has an orange top you need toyota type T-IV, if you want to stick to the original. Not sure how your transmission will like the other fluid. The change from type T-IV to WS fluid happened during the 2007 model year.

If you've replaced the filter and the fluid is fairly fresh, then it might be snake-oil time. Best wishes, and please let us know how it goes.
 

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Discussion Starter · #8 ·
I did a transmission fluid drain and fill in March. The filter should have been replaced at the time. I paid a shop to do it and I can check the receipt later to make sure. It does use the WS which I carry a bottle of and that's what I topped it off with. The current color is obviously not in the brand new pink range. It's more light purple. Doesn't particularly smell burnt but I'm also not familiar enough to be able to tell exactly.

I just drove it about 10 miles to get my tires rotated and didn't notice a slip. It already wasn't happening too frequently so maybe the top up was enough to help? Or maybe it's not slipping and it's all just in my head.... I'll drive some more and try to get a better sense of what's really going on.
 

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Drain and fill usually means draining the fluid through the drain plug and not dropping the pan. Check your receipt to see if the pan was dropped/filter changed. If it wasn't, at 200K miles, it should be changed. Now, if you've owned the van since new and did a D&F every 30K miles then the filter is probably fine. But if you don't know the trans maintenance history then definitely change the filter.

From my experience it takes a bit more than a quart low for the trans to start slipping.
 

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Discussion Starter · #10 ·
Drain and fill usually means draining the fluid through the drain plug and not dropping the pan. Check your receipt to see if the pan was dropped/filter changed. If it wasn't, at 200K miles, it should be changed. Now, if you've owned the van since new and did a D&F every 30K miles then the filter is probably fine. But if you don't know the trans maintenance history then definitely change the filter.

From my experience it takes a bit more than a quart low for the trans to start slipping.
you were right. turns out, the filter was not changed. I have not owned it since new and I doubt that the transmission filter was changed by the previous owner.
 

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I had a 2004 Envoy I bought in 2019, that the trans started slipping a bit towing a pop-up camper on the interstate. Bought for only $4k, ended up selling for $600 that year to a guy that probably fixed it himself and resold or is still driving it.

In hindsight I’d wished I’d tried first a fluid and filter change, and if it kept slipping try some Lucas or other similar “snake oil.” As others have said, if it’s already slipping, what do you have to loose? Mostly In just curious because I like trying things, so I’m wondering if it would have worked, and if so, for how long?

In your case the above advice seems solid. Personally, I’d try a fluid/filter change. If it keeps slipping, try some snake oil. If that ultimately doesn’t work, you’re out like $200?

You could always quote out a transmission rebuild too at a local transmission shop, if the vehicle is otherwise still in good shape. And unless someone here knows that the “snake oil” will cause issues with a rebuild, you can try that before doing the rebuild too.
 

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Discussion Starter · #12 ·
I had a 2004 Envoy I bought in 2019, that the trans started slipping a bit towing a pop-up camper on the interstate. Bought for only $4k, ended up selling for $600 that year to a guy that probably fixed it himself and resold or is still driving it.

In hindsight I’d wished I’d tried first a fluid and filter change, and if it kept slipping try some Lucas or other similar “snake oil.” As others have said, if it’s already slipping, what do you have to loose? Mostly In just curious because I like trying things, so I’m wondering if it would have worked, and if so, for how long?

In your case the above advice seems solid. Personally, I’d try a fluid/filter change. If it keeps slipping, try some snake oil. If that ultimately doesn’t work, you’re out like $200?

You could always quote out a transmission rebuild too at a local transmission shop, if the vehicle is otherwise still in good shape. And unless someone here knows that the “snake oil” will cause issues with a rebuild, you can try that before doing the rebuild too.
There's a shop I've been using for years and years. I called them up and they told me to bring it in after Thanksgiving so they could take a look. They actually brought up the stopslip first -- if they confirm that it is slipping, their first recommendation was to do another drain/fill and this time add a bottle of stopslip. If that helps, great. If that doesn't, given the age of the vehicle (2007 with 200k miles) it's probably just time that the transmission is dying. I am very happy with its current state otherwise, but I will most likely end up consulting with them to see if it would be worth a rebuild in that case.

My last car's transmission died in the middle of the highway during rush hour so I've been scarred about transmission issues since... so really trying to not have that happen again.
 

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My memory from reading posts at this site over the years is that the early generation 2 Siennas did not have transmission fluid filters, but only a metal screen. That may have changed in later production years when the fluid standard changed to “WS”— I don’t know.
 

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My '04 has a build date of Sept. '03. It has a Dacron polyester filter. The first generation Siennas had simple screens and unfortunately the Toyota parts catalog never changed the wording for the second generation, hence the confusion. All 2nd gen Siennas have a steel sandwich filter filled with quite a bit of polyester filter material. Pictures of the cut open filter here.
 

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Discussion Starter · #16 ·
I just drove from SF to LA today and was paying attention to the transmission the whole drive. I've gathered a bit more info regarding its behavior and it seems to be a bit specific:

  • when at very low speeds, basically starting from a stop
  • be in first gear
  • moving up an incline, steep enough that keeping it in D without giving gas will roll the car backwards

when I start giving gas here, the car will stop rolling back and start moving forward as it should, but the time delay between the RPM going up and the vehicle speed matching what should be appropriate is about one mississippi. the car then shifts into second and everything is fine. under no other driving condition did I notice anything resembling a slip. I'm starting to think if what I initially took to mean transmission slippage may not actually be the case -- could actually be a sticking solenoid or torque converter? I've had reason in the past to be a little suspicious of the health of the torque converter, so...

shop isn't open until Saturday so I won't be able to have them test drive and see what they think until then, but I'm going to try to observe as much as I can until then.
 

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when I start giving gas here, the car will stop rolling back and start moving forward as it should, but the time delay between the RPM going up and the vehicle speed matching what should be appropriate is about one mississippi. the car then shifts into second and everything is fine. under no other driving condition did I notice anything resembling a slip. I'm starting to think if what I initially took to mean transmission slippage may not actually be the case -- could actually be a sticking solenoid or torque converter? I've had reason in the past to be a little suspicious of the health of the torque converter, so...
Dirty throttle body? Before I cleaned mine there'd be a little hitch in the getalong.
 

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I have an 07 LE with just about 200k miles on it.

I think my transmission is starting to slip a little. When starting from a stop or at very low speeds, it seems like every once in a while the RPM goes up but the speed doesn't, as if the transmission does not want to shift. It goes away very quickly when I feather the gas pedal.

My search says the most common cause of slipping trans is low trans fluid. I checked while it was warm, with the engine running, and it was about an inch lower than the upper(hot) range on the dipstick. I topped up but it didn't need very much to return to the right range.

So I'm thinking maybe I can add some of the stop slip stuff as well. Does anyone have experience with this? My trans fluid level is normal now so I'm not sure if adding this will have me end up with an overfilled fluid level, or if it's meant to be used like that. Or more importantly, if it's even worth using at all.
Try Motorcraft Transmission Friction Modifier. Is an amazing product. Handle with care because smells like rotting hell.
Genuine Ford Fluid XL-3 Friction Modifier Additive - 4 oz.
https://a.co/d/1bj2nLH
 

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Discussion Starter · #20 ·
Well, this supposed slip is not reproducible on command. It has not happened in the last 500 miles or so of driving, and I only noticed it twice or so before that. The shop is hesitant to call it an actual issue with the transmission at this point. If it happens more often or more obviously, that's when I should bring it back in. They did however say that considering the age of the transmission (it is OEM with 200k miles), if it really is slipping then the only real action to take is to replace the transmission. At least in the experience of these guys, a rebuild is not worth it because 9 out of 10 times the transmission case tends to not seal back up right even if they torque it properly. Quote on a Toyota remanufactured transmission (3 yr / many miles warranty) + labor was $5k. I think I'll just drive around some more and if it turns out to be a real issue, I will then be at a crossroads of deciding if I want to do the transmission replacement. $5k is a good chunk of money but I don't know if I can find an otherwise equivalent car for $5k, and even then that's going to come with a lot of unknowns. The joys of owning a 15 yo car!
 
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