Re: [Chevelle-List] No 3 - 2 downshift

[Richard Milkiewicz]

Kelly, I was sure your truck had a detent at the carb. I'll have to check my manuals. The switch on the floor is a kickdown. Some people call it a detent but really it's a kickdown switch. When you are going to pass a car and you press the pedal down to activate the switch, it sends an electrical signal to the solenoid in the trans and drops it to a lower gear to pass. When you floor it from a stop it signals the trans to shift faster. You can get a modulator at any good auto parts store. $35 to $45 bucks. If you have a Myti Vac or similar vacuum device, you can check it with this. You have to remove it to do this. One bolt and pull it out. The diaphragm should move as you pull vacuum. Not much to go bad in there but they do. If the diaphragm is broken you usually see white smoke out the back. This is because the carb is sucking trans fluid. Anyway, I have to look this up as soon as I locate my manual. I'm not the neatest person. I wouldn't change the modulator unless you know for sure it's bad. If it's just the up shift and down shift you don't like save your money. If you have to back off the gas to shift, then I would replace it. Rich ----- Original Message ----- From: Kelly C. Hanna To: [EMAIL PROTECTED] Sent: Monday, July 29, 2002 8:48 AM Subject: Re: [Chevelle-List] No 3 - 2 downshift >Kelly, it sounds like the detent switch on the carb  is bad or stuck. This switch controls the down shifts. If it's >bad the trans  will still down shift, you just won't be able to "feel" 3 to 2. It won't hurt  the trans to drive like >this, it just doesn't feel right. If the switch appears  to be OK check the wires from it to the trans.   I checked the carb, but no wires going or coming. The switch I was told about is on the accelerator pedal and all seems to be ok with that.   > This switch >won't affect  your upshifts. A more likely reason would be the vacume modulator. Look for  cracks in the vacume line >at the carb where the rubber hose slips on to the  metal tube and also at the trans where it slips on to the >modulator. These hoses  dry out and crack and allow vacume leaks.   I replaced all the vacuum hoses the first day I had it. Figured they all could use a new one.   >The modulator may also be loose or bad.  If the mod. >is bad go with an after market. These are adjustable.   Hmmm, I'll have to check it. Any idea what one costs and where I get it?   >Anything else  would be internal and a trans man would need to >open it up. But I would say 95%  of the time, these are the reasons for your problem. Unless you really pound on  that >400, it will last forever. Oh, one last thing. If I remember right, there  is a fuse for the detent switch. If all >this checks out OK on the detent, it may  just need an adjustment. Hope this helps you out. >If not, let me know and I will dig out my  factory manuals.   I'll check the modulator....how will I know it's bad if (it's not loose)? I like the 400's and awful lot. I will eventually get someone to rebuild this one and put a shift kit in it. I just wish I could get it to hang in 1st a little longer right now. I can live without the 3-2 downshift, I can always do it manually.   Thanks for the info.... Kelly & Jana Hanna www.hannawoodworks.com