350 Transmission shifting - ClassicOldsmobile.com

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Old July 7th, 2017, 07:19 AM   #1  
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350 Transmission shifting

Having issues with my 72 Olds 350 trans shifting. I had been getting a slow leak when it sits for a long time. I think it is coming from the yokes that goes goes into trans but very hard to determine. When I bought the car the guy slipped out the drive shaft to tow it and I think that is maybe wear it comes from. It has been getting harder to shift. The 1st gear going to 2nd shifts really hard. Then to go from 2nd to 3rd you have to be at least 45 mph before it goes into 3rd. Before I could back off the gas and it would go into it 3rd. Now it is getting harder. I replaced the trans module last year thought that was the issue did'nt seem to fix it. I have check the vacuum advanced and shops it has been too the lines seem good. I recently had a brand new Holley 650 Carb installed and now it seems to be shifting harder. I do not want to spend a ton of money on this trans as I have fresh rebuilt 455 and purchasing a TH400 for that engine to be installed in the winter or fall. Just looking to get by this year for the Woodward dream cruise in August in MI. Any suggestions?? The trans fluid doesn't smell burnt is dark color it is very red. Due to amount that leaks out it usually has fresh fluid at all times. I don't drive it that much but figured I would ask you Olds gear heads you guys always have so much good knowledge. Thanks is advance.
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Old August 13th, 2017, 12:23 AM   #2  
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The vacuum line where it plugs into the manifold fitting will sometimes build up carbon. Try sticking a paper clip into the vacuum line,, if it won't go into the hole then take a small drill bit and clean out the line .. the plug is usually in the small nipple that slips into manifold fitting
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Old August 13th, 2017, 04:59 AM   #3  
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Check the vacuum lines that run from the carb to vacuum modulator on the trans for cracks and/or trans fluid. If they are ok change the modulator.
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