Intermittant transmission issues turn out to be alternator.

[iis4isaac]

Not sure if anyone else has run into this, especially when people immediately run to the glycol test. Transmissions shifting hard, slipping, shifting at the wrong time. My gf took her 01 v70 xc to an import shop, they charged her $75 for a glycol test and told her the transmission was shot. Reading forums seems to corroborate this theory. I took it to a transmission specialty shop where I know the owner has rebuilt several of these generation transmissions.

He put his computer on it and put it through the paces. The result, her alternator is not putting out enough voltage. Which causes the transmission to not fully engage valves and providing incorrect fluid pressure. He said with a fully charged battery it runs fine, but as you watch the voltage drop the transmission starts to misbehave. The indicator doesn't seem to come on until it's very low.

He said he had another Volvo with the same problem a few months ago. so I'm going to do a pressure test on the radiator to see if our glycol test is legit. If so, I'll replace the radiator and power flush the transmission. If not, it's just a flush.

I thought I'd throw this out there for folks to keep in mind in the testing process. Watch your voltage.

-Isaac

[draser]

Very good point, it seems the charging circuit can cause all kinds of greef.. wondering why the battery light did not catch that..