I have a 1990 Chevy one ton HD (G30) type van. The dealer tells me that going by my VIN number I have a turbo 400 transmission without overdrive in it. Last week my son loaded about 2000 lbs into it and drove ten miles. He says it was running ok just afterwards but two days later it is now exhibiting shift problems. In drive you have to really get the RPM's up before it will shift into second and when it does it goes in pretty hard. Once I got it into second I gave it some more gas to try to get it into third, but it seemed to not want to shift into that either without further RPM's, and I didn't want to push it further. The fluid level is just a slight bit high, it is not burned and there is no slipping that I could detect. Engine idle speed does not seem to be excessivly fast as might be caused by a vacuum leak although I have not investigated the modulator or the line yet so I suppose that a leak is possible. A few weeks ago I replaced the fuel lines from the throttle body back to the tank. I noticed that the vacuum line to the modulator was a little rusty but it seemed ok. I was working near it but I don't believe that I hit it or stressed it. I just drove tested the truck today for the first time after getting it back and I didn't try to drive too far but the symptoms are the same on cold take off as they are after putting a few miles on the truck. Can someone please explain how these transmissions shift, perhaps outline a procedure for troubleshooting this problem, and possibly offer an opinion as to what might be the most common explanation for my problem? Thanks very much for any assistance. Lenny Stein.
- posted
18 years ago