Snow buildup casuing tranny probs?

[gavin]

Ok, so here's the deal. Yesterday, it started snowing pretty hard (for the first time this year), and on the way to work my truck ran fine. Went out for lunch, all good and dandy.
Well when I got off work, and started my treck home, my tranny wasn't shifting right. It was getting up to about 3000 RPM before it would shift, and when it did finally shift, it was VERY hard (almost felt like my tires were spinning on ice, then hit a dry spot)
So I get on the highway, doin about 40-50, with the RPMs at about 3300 or so... it's also not shifting into overdrive (no torque converter lockup).
Well I get up today to do some errands, and we have about a foot of snow. Anyway, I let my truck warm up for about 20 min (mainly to thaw out the windsheild and whatnot), and head into town. Same problems; not shifting worth a damn.
Well I gotta go get my IM done, so I head there. My truck's in the shop for about 20-30 minutes, thawing pretty good. I get done there, and go to do my other errands. Well guess what; it's shifting fine now. Overdrive works. No hard shifts, no running up to 3000 RPM at a very low throttle.

So is it possible for a snow/slush/ice buildup to cause the tranny to not shift right?

Sorry for the long post; I figured I should explain as much as I can to get a good reply from you guys.

 

[Glacier991]

Man I have never heard of that....when was the last time you changed the trannie fluid? That is a curious one. I regularly run my 92 ex in snow that can (on VERY rare occasion) be up to the bumper and have never had a problem. (Yeah we get BIG snows off the Pacific up in the Sierra...)

 

[gavin]

yeah, I know it sounds odd... I just changed the tranny fluid a few months ago, so I doubt it's that. I haven't checked the fluid level lately, but seeing as how it's shifting just fine now, I don't think that would be it.
The only thing that leads me to a snow/slush/ice buildup, is the fact that the problem went away, after being in a heated shop for a good 20-30 minutes. Although it could just be a coincidence...

 

[Brain]

How cold was it? The fluid does start to solidify at extremely cold temperatures, and thick fluid could cause some of the things you are talking about. If I'm not mistaken, your truck has an auxilary cooler in the front without a thermal bypass. A short warmup period and a 40-50 MPH wind chill might have kept the tranny from operating right. Did you use regular Mercon V fluid (synthetic blend) for the change, or full synthetic fluid? The blends will have part of them (the non-synth components) jellify at low temps, where the full synthetics will keep flowing at lower temps. The transmission does have to work harder in the snow, as it is constantly climbing a hill of snow. If the problem persists, I'd think about getting/installing a manual bypass valve to keep fluid from flowing in the external cooler and just have the cooler in the radiator tank keeping it cool (or warm, depending). Just a thought.

 

[gavin]

it's not excrutiating cold out.. like mid-20s. Plus, as I was driving to town, about 6 miles down the highway (goin between 50-60) it finally shifts into 4th, but still wouldn't shift into O/D. And even after that the shifts were funny. So I doubt it's the cold fluid.

 

[Brain]

Yeah, that's not as cold as I was thinking Alaska would be....I was thinking somthing in the negatives and then subtract some for wind chill. I agree with you that it probably isn't the cold fluid. It was just a thought.

 

[Glacier991]

I'm mystified. Try as I might.... nothing in the equation remotely explains lack of OD to my mind. Yet there must be SOME connection.... electrical?