No shift after changing converter. * sent converter to Coan for inspection * new kickdown switch, it clicks. * new vac modulator, holds vacuum. * govenor free and good gears. * rebuilt transmission, new filter. What's next???
Sounds like a sticking 1-2 shift valve......I assume it goes forwards and backwards as it should just no upshift?
Will do. Thanks. We will also borrow a pressure gauge. Not sure what pressure numbers to watch for. Has long blue spring in pump.
If I remember correctly, that line pressure and reverse pressure seem good. Who rebuilt the transmission, and if it wasn't you, what do they have to say about it? If the converter wasn't seated, you wouldn't have any pressure. Like Ben asked, does it have R and 1st?
Yes, just "slow" and reverse. Flex plate and 3 pads were kind of close fit. Bell housing to 3 pads were 1 3/8". My friend rebuilt it. He is going to "check the valve body" later this week. Said he may swap to a spare VB # 8623569 from a "70 BT" low mileage transmission.
Geez, All your problems started with this converter. http://v8buick.com/index.php?threads/coan-20320-2-used-converter-problems.351742/
Yes, And sent it to coan for inspection. "No problem" they said. This is causing me to loose sleep and money!
I have one. 3500 stall-JW converter. Hate to give up my 15 year dream of a 20320-2 Coan. But...is the Coan causing the problem??? A big part of our hobby involves trying different things to improve our cars performance and reliability. We want to test or experiment with many of our ideas. Sharing the results, good or bad is what we do here all the time. If I trash my Coan now, I will never have tried my dream converter, and nearly $2000 spent will leave me quite depressed. I don't know what to do right now. Will see if my friend can fix the shift problem. He can't work much due to age and health. I'll keep posting any progress.
Throw the JW converter in there to see if the problem still happens or not and rule out the converter as the suspect?
Ok maybe I missed something, is this a fresh build trans, or a good known working trans with just a converter change. If it's a gear change issue.......the converter has nothing to do with shifting When you say its "slow" what do you mean.........like the car moves forward but feels like it's in 2nd gear???? If the 1-2 shift valve stick or gets jammed by trash..........it will stay in second gear even if you put it in low 1..........it should make the 2-3 shift............so it you can get it to 50 pull it down into 2nd you should feel the downshift.........let it coast down to 20 pull it into 1st, if no down shift I would pull that out out and clean it. Had this happen more than once in life. When you drive it does it seem like its slipping..........or gripping just not moving
Was perfect until the Coan converter was installed. Drove it around the block. Never felt a shift. Got some stall when I taped the throttle. Removed the converter, inspected at Coan factory. * Same result. Rebuilt trans. * Same result. Cleaned the govenor, new vacuum modulator & hoses, tested kickdown switch. Checked pressure. * Same result.
Take the governor out, wedge some rubber hose in the weights, the idea is to use the hose to keep the weights out like they would be at high speeds. Reinstall the govenor. You now have an extremely primitive manual valve body. If you put the shifter in drive, you should have 3rd gear. Don’t beat on the trans, the idea is to make sure the valve body is capable of shifting. If your still stick in 1st gear, most likely the 1-2 shift valve is stuck in the upshift position. Other idea is to make sure the modulator valve is free to move
