Yet another transmission question - slipping

BMWFan · Post by **BMWFan** » 11 Feb 2023, 07:49

With that common problem with older Volvo SUVs where the transmissions start to flare/slip in between shifting and then "banging" into the next gear. Sometimes they can also just be in a slip/neutral condition for some time before shifting. My 2007 Volvo XC90 does this. I've replaced the transmission fluid and had the computer settings reset about 80k miles ago and it was better for a little while, but still did it soon after, getting worse as the miles passed. It only does this in the hot summer and/or rush-hour (stop and go) traffic.

BUT -- In the Minnesota winter, it works great all winter long. When it's cold, and the transmission isn't overheated in rush hour traffic, it will shift fine. We call it our winter vehicle, driving it when the temperatures are under +40F. Above that, and it will start slipping more and more the higher the temperatures (or transmission temperature) gets.

Could this be a fluid problem? Either viscosity (thin when hot) or maybe not enough (or too much) that might be able to be corrected if I go to a shop and have them professionally change the fluid? Or is the valve body fix the only way around this? Because it drives perfect in the winter makes me question if it could be the valve body part that is bad.

Thanks.

Post by **MoVolvos** » 11 Feb 2023, 09:07

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Since you already know it is heat related... Here is a short but good video on installing an auxiliary transmission cooler though it's for an Odyssey and it does not bypass the radiator.

I have the Hayden 1405 on my 03 Odyssey but it completely bypasses the radiator. The transmission temp will always be close to that of the radiator coolant temp or higher in the factory setup. When bypassed the radiator will have ambient temp and transmission heat as the two to determine fluid temp.

Eliminated the slight slippage during the summer. Has 245K or so and I purchased this at 154K. Helps that I've flushed it a few time beside a drain and fill or two. The transmission bypass was done around 4 plus years ago if my memory serves me right.

As for the transmission fluid I've purchased 4 to 5 cases of the Havoline over the last 4 plus years and it's worked in all the cars thus far including power steering. 00 S70, 03 GS300, 03 Odyssey, 03 S80 T6, 05 GS430.
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(www.amazon.com/HAVOLINE-226536481-12pk- ... B074JLXF34)
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https://www.ebay.com/itm/194073153863?e ... BMlsf_k8hh

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bguzz · Post by **bguzz** » 11 Feb 2023, 20:06

It sounds like you might be having a transmission oil viscosity issue...are you sure when the fluid was replaced it was done with a genuine Aisin JWS 3309 approved fluid? Same as Toyota type 4 I think. If it was replaced with a multipurpose fluid that might be the issue. I would have expected that you had issues as lower temps if it was the valve body. The TF80-SC transmission is known for going through torque converters quickly, so the wrong fluid or never changing it can speed its demise. Also the fluid change procedure and verifying its correct level is a bit unusual, if it wasn't a dealer or volvo experienced place that changed it, that could be concerning too.

Post by **Krons** » 12 Feb 2023, 07:21

I wonder if a thicker additive like the Lucas Transmission Stop Slip may help. While those are generally not advised, based on your symptoms something to help in high heat may be worth a try.

chitownV · Post by **chitownV** » 14 Feb 2023, 20:10

In this situation, I would first ask how many miles are on the XC90, what fluid was used, and which engine? Was the fluid change a simple drain & fill, only changing maximum 4 quarts?

Transmission fluid for the TF-80SC should be first changed at 60k-80k miles, then 20k-40k mile intervals after that. I used Mobil 3309 for two ~25k mile intervals and could feel the fluid break down in that short span. It could be the friction modifiers, it could be the conventional oil used, who knows. Oils shear down, meaning their hot viscosity gets thinner with wear and use. If the last fluid change was 80k miles ago and it was only done once, then I first see a transmission fluid maintenance problem.

If you used Mobil 3309 and it's not working out, then try a different JWS-3309/T-IV fluid out there. Aisin makes fluid, Volvo, Toyota T-IV, and the one I currently use, full-synthetic Ravenol T-IV. Since I did two Mobil 3309 fluid changes (around 50k miles total) as my first transmission fluid changes, I can first-hand tell the difference between Mobil's fluid and Revenol's full synthetic. Ravenol's fluid is very consistent, hot, cold, and at 25k miles...consistent. It shifts better and smoother at 165k miles than it did at 100k miles. This is how I knew Mobil 3309 fluid did not last. Mobil is the most tried and tested, as it's also used in the 5-speed auto, but for the TF-80SC, there are better fluids out there that may work better.

If you want to stay with conventional fluid, I had people reach out to me saying Toyota's T-IV fluid is pretty good, when compared to Mobil 3309. It's good to hear from those who have tried more than one brand of fluid as it gives both real-world feedback and results.

If a multi-spec transmission fluid was used (universal), then that's a clear problem and the fluid should be changed right away with the correct spec.

dikidera · Post by **dikidera** » 15 Feb 2023, 13:13

I get the computer was reset of all adaptations, but you didn't specify when you changed the oil and if you reset the oil counter or more commonly known as oil degradation counter. It tracks how many times the oil reached temps over the norm, I don't know if it was 150f or 150c, I did not check properly, but then it sets some flags and causes the shifts to worsen to save the gearbox.

As an absolute last resort, try to reset this counter and only then give up and go the hard route with replacement.

Addendum. If you truly replaced the oil 80k miles, you've pretty much ruined the box, the oil should be replaced every 60k kilometers and you are well past those.

As for fluid, I was told that Volvo have their own friction modifiers in their version of the 3309 oil. How true this is...is unclear.

BMWFan · Post by **BMWFan** » 15 Feb 2023, 19:07

It's a 2007 XC90 V8. There are 200k miles on the vehicle. I replaced the fluid at around 125k with Mobil 3309 ATF using a "flush" method by removing the Trans cooling lines and running the vehicle, draining the old while sucking the new. There's no dipstick, so I'm not sure the level was perfect when finished.

The software was updated and transmission adaption was not reset at that ATF replacement time because I didn't know it was needed. But at about 180k-190k I did take it to the Volvo dealer and do that. It shifted differently after that, but still flared between shifts. It's doing that between most of the gears when it's hot outside. Winter temps (45F and colder) it shifts fine.

chitownV · Post by **chitownV** » 15 Feb 2023, 19:34

Why not try changing the fluid again as the first step to see if you will have any improvements. Changing it once in 200k miles is not enough. If you did it before, then you know what’s involved. Also, there are many YouTube videos to help you level the fluid from the drain/level plugs. Make sure to get a new o-ring for the level plug.

Just remember it might take 500-1k miles on the new fluid and for enough data, such as line pressure, shifting, etc., to feel the computer adapt.

dikidera · Post by **dikidera** » 16 Feb 2023, 03:09

BMWFan wrote: ↑15 Feb 2023, 19:07 It's a 2007 XC90 V8. There are 200k miles on the vehicle. I replaced the fluid at around 125k with Mobil 3309 ATF using a "flush" method by removing the Trans cooling lines and running the vehicle, draining the old while sucking the new. There's no dipstick, so I'm not sure the level was perfect when finished.

The software was updated and transmission adaption was not reset at that ATF replacement time because I didn't know it was needed. But at about 180k-190k I did take it to the Volvo dealer and do that. It shifted differently after that, but still flared between shifts. It's doing that between most of the gears when it's hot outside. Winter temps (45F and colder) it shifts fine.

Well firstly, you needed to change the oil again at least 40k miles ago. And needed to clear the counter. Then after awhile, the same procedure. As far as I know these trannys need the exact amount of oil, no more, no less.

Also let me be clear. The oil degradation counter is a separate thing from Adaptations. They are two different things.

BMWFan · Post by **BMWFan** » 16 Feb 2023, 20:22

I just ordered the FCP Volvo Transmission Service Kit plus 4 extra Liters of fluid from FCP Euro and will change the fluid. I'll have 12 Liters of ATF so can drain/fill 3x instead of two. I do have VIDA software and interface, but it quit working on my old laptop. I might try to install it on the wife's laptop. If that doesn't work, I'll take it in for a reset on the oil counter after that.