Erratic Shifting and Engine Temp
I am experiencing a problem with the transmission. I’m not sure where the exact issue lies or if this problem is just a symptom of another system failing, but the end result is the transmission occasionally won’t upshift out of 2nd and sometimes 3rd gear or into overdrive. Here’s the particulars:
On extremely warm days (mid to upper 90’s) and on trips over 200 miles (some shorter) the transmission won’t upshift properly – or else it will shift very erratically. This will occur in stop-and-go traffic or in rolling terrain – it’s not picky when it decides to do this. It’ll run up to 3,000 to 3,500 rpm (or higher) and I’ll still be doing only 35 to 40 mph. I should be doing 90 at that rpm level. While this is going on, the engine temperature will rapidly begin to climb to dangerous levels. I’ve never let it get to the “red zone” and if I pull over and stop, the temp will drop to near normal (slightly above normal).
I don’t know if there’s a wheel speed sensor of some sort overheating and sending false or errant information to the transmission or if there’s some other cause. If I keep the engine rpm’s down to around 2,000, the temperature will hold just slightly above normal – any increase in rpm’s, the temp goes higher. Sometimes when I let off the gas while this is happening, the rpm’s will drop and it’ll shift and the temp will come down, sometimes not … and I’ll slow down as if it were a manual transmission left in a higher gear and not just coast like an automatic.
Coolant level is normal and I had a complete transmission flush about 18 months ago. It has approx. 141,000 miles on it.
Of course, when I took it to my independent mechanic, it was running fine and he could not find any error codes.
Any ideas?
PS - I'm leaving on a 300 mile trip in about 15 minutes ... wish me luck!
Last edited by Bluegrass-XC; 07-17-2009 at 10:10 AM.
Mike
Bluegrass-XC
(Somewhere on the Space Coast)
2000 V70 SE Cross Country
1987 Chevy K5 Blazer 4x4 (in Blazer Heaven)
"Better to remain silent and be thought a fool -
than to open your mouth and remove all doubt".
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