th350 problem any ideas?
#1
th350 problem any ideas?
hey again, today in Wisconsin it was a pretty hot day, 90 degrees, and more then likely 100 plus in the sun and I was driving my Camaro around and my transmission was acting up, and doing some weird things and I don't know if it was from the heat or if my trans is going out the door? I'm not sure what, but here are the symptoms
-I would put the trans into L1 (1st) and it would shift right by it, and go to second
-when I was cruising at 35 mph, barely using the gas, it would shift between 2nd and 3rd for no reason
and now, that I let the engine and trans sit for a good 2 hours to cool, its fine. on another note I also had my engine bog out for a second when I was coming out of a stoplight, idk if that because of my ****ty quadrajet carb or no. None of my temp lights were on, although I dont know exact temps from the tranny or engine because I don't have any hooked up. if you guys could help me out that would be awesome, thanks!
-I would put the trans into L1 (1st) and it would shift right by it, and go to second
-when I was cruising at 35 mph, barely using the gas, it would shift between 2nd and 3rd for no reason
and now, that I let the engine and trans sit for a good 2 hours to cool, its fine. on another note I also had my engine bog out for a second when I was coming out of a stoplight, idk if that because of my ****ty quadrajet carb or no. None of my temp lights were on, although I dont know exact temps from the tranny or engine because I don't have any hooked up. if you guys could help me out that would be awesome, thanks!
Last edited by Evan383; 06-19-2016 at 09:34 PM.
#4
When put in 1st gear manually, it will (should) hold in first until you reach about 5500 rpm's, at which point the governor (which has centrifugal weights) overrides hydraulic pressure and forces the 1-2 shift valve in the valve body to actuate. If this is happening sooner (lower rpm), the governor is likely to be faulty. Perhaps the weights are getting bound up from the heat and getting somewhat stuck in the out position.
#7
well I checked the governor and the weights move and the valve inside it moves, so I'm not exactly sure what the problem is, the vacuum modulator could be bad maybe? I feel like that wouldn't cause my symptoms though
#8
My thoughts are these: (on 1962 and later)
1. If trans is manually selected for 1st gear, it stays in the selected gear regardless of RPM/MPH.
2. If 2nd gear manually selected, yes, it will upshift from 1st and downshift to 1st on its own.
3. When D is selected, gas pedal position, hence light throttle or heavy throttle, trans will upshift accordingly - light throttle = early upshift; heavy throttle = later upshift - and yes vacuum modulator helps make this decision.
If you add an external cooler, place it between the radiator and trans on the return line to trans - usually the top tube of radiator - check flow making sure and you can never have a big enough cooler.
Trans built before 1962, some of them, if 2nd gear was selected, 2nd gear was the chosen regardless of speed. This is how several elder people traveled on ice - no slippage - select 2nd gear no 1st was used by trans - these instructions were in the Owner's Manual.
1. If trans is manually selected for 1st gear, it stays in the selected gear regardless of RPM/MPH.
2. If 2nd gear manually selected, yes, it will upshift from 1st and downshift to 1st on its own.
3. When D is selected, gas pedal position, hence light throttle or heavy throttle, trans will upshift accordingly - light throttle = early upshift; heavy throttle = later upshift - and yes vacuum modulator helps make this decision.
If you add an external cooler, place it between the radiator and trans on the return line to trans - usually the top tube of radiator - check flow making sure and you can never have a big enough cooler.
Trans built before 1962, some of them, if 2nd gear was selected, 2nd gear was the chosen regardless of speed. This is how several elder people traveled on ice - no slippage - select 2nd gear no 1st was used by trans - these instructions were in the Owner's Manual.
#9
You lost me, what transmission are you referring to. 1962? The TH350 (what we're talking about here) came out in 1969.
#10
The trans I'm referring to where the DynaGlide, DynaFlow, Hydra-matic (Pontiac), Ford-O-Matic, Cruise-O-Matic, Jet-Away, Presto-Matic, Torqueflite, and Powerflite.
The older ones, these are, and they stayed in the selected gear, no upshifts, no downshifts.
You manually selected 2nd, 2nd gear was it, no first gear - was great for ice driving.
I have had a Chev THM350 and when I selected manually 1st, it stayed in first, no upshift, stock valvebody and shifted normally in Drive going up and going down.
Yes governor did upshift the trans at WOT.
The older ones, these are, and they stayed in the selected gear, no upshifts, no downshifts.
You manually selected 2nd, 2nd gear was it, no first gear - was great for ice driving.
I have had a Chev THM350 and when I selected manually 1st, it stayed in first, no upshift, stock valvebody and shifted normally in Drive going up and going down.
Yes governor did upshift the trans at WOT.