New Owner! Tranmission cutting out on freeway :/

[youropeen]

You're welcome.

[OslosisJones]

You're welcome.

Yeah, yeah. I was skeptical about the codes until the fuel pressure tripped the check engine light. At that point it was fairly straighforward. Glad I took the advice on picking up a DiCE unit!

I've been thinking about writing up all the things to check before going down the transmission route. Seems typical for some posters to jump to conclusions about failing transmissions when there is often a much more benign problem that manifests itself in abnormal shifting/engaging issues (not just this thread, but many others I read through when trying to diagnose my own problem).

To be fair I threw a wrench in things when I described it as 'slipping' when it was really just dropping out of gear, presumably because the engine lost power due to insufficient fuel pressure (sensor was reading higher than actual).

Glad you stayed with it and did not listen to the others that were saying "You need a new transmission". I install a trans cooler on every ATX vehicle I have ever had and have never heard of a ATX having issues with the fluid being to cold. A cheap tube and fin design cooler only drops it a few degrees but could make the difference in the end. The design of the XC70 leaves lots of room to add one so I ended up putting one of the large ones on. Cheap insurance, along with changing the fluid more often.
TomK

Approximately what size did you install? Would the $50-100 Hayden units on Amazon be sufficient? Most of these seem really small... Would the units with a fan fit or be necessary?

I've seen pictures of some setups (Astro's maybe?) and I like the idea of mounting a filter and a bypass, even if I don't regulary drive in sub-zero temps.

Probably rather spend that $100-200 on upgrading the sound system right now. I have ATF so I'll continue doing D&F and maybe work up to adding an external cooler at some later time.

[vtl]

Approximately what size did you install? Would the $50-100 Hayden units on Amazon be sufficient? Most of these seem really small... Would the units with a fan fit or be necessary?

Cooler is a safety countermeasure for overheating transmission. When transmission operates at normal temperatures, cooler does not affect ATF temperature much. I don't see a need for bypass valve, since ATF is heated by coolant anyway. Didn't see any problem in MA winters.

With this display https://github.com/vtl/volvo-ddd/ its quite interesting to see how car reacts to different loads. In short, in hot days ATF stays at about same temperature as engine's coolant (approx. 78 C), maybe slightly higher.

[kutcht1]

I believe this is the one I installed, Hayden 1405.

http://www.ebay.com/itm/HAYDEN-TRANS...3D321192175094

Plate coolers are better with less surface area as I have one on my Mazda Millenia.
Since there is lots of room I went with the tube/fin style.
TomK