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View Full Version : Transmission?


bigtallguy
11-15-2003, 10:31
Well, I just got the new IP as most of you know which was discouraging enough since I just bought my truck, but now it's doing something else. When I get up to about 50 mph, it shudders/vibrates until I either give it gas or let off a little. It doesn't do this at any other speeds and only after it gets into OD. It almost seems like it is shifting into OD too early. What could the problem be?
bigtallguy
11-16-2003, 17:23
Anybody?
rjschoolcraft
11-17-2003, 04:36
what speed is the engine turning when this happens?
bigtallguy
11-17-2003, 07:23
Usually between 1400 and 1600 rpms.
rjschoolcraft
11-17-2003, 11:53
I'm guessing that this occurs with a locked converter...

At low engine speeds with a locked converter, the drive line will shudder and seems to experience an excitation of a resonant frequency. My Suburban will do this under the conditions that have been described. I would say that this is normal and nothing to worry about.
damork
11-17-2003, 12:08
Go to www.sonnax.com (http://www.sonnax.com) - seems there are some 4L80E autos that have shuddering problems at lockup. They have a kit to address it if it is truly caused by a valve.
JohnC
11-17-2003, 15:25
Could be the EGR. Put a plug inthe line going to the EGR valve after the "T" for the baro sensor, for test purposes only, of course. This disables the EGR. If the shutter goes away, well, you have an EGR problem...