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Trans fluid burping out fill/level tube on startup

Jeff C.

Jeff C.

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Hello all, my first post. I changed gasket and filter for the TH350 and filled with correct amount . The level , after reaching temp, read low so I added maybe a half quart . Now , when I start after a couple/few weeks I get trans fluid burping out of the fill/level tube, about 1/8 qt or less, for a few seconds then stops. Aside from the mess, dripping on the exhaust manifold, etc, I wonder WHY???? Filter on wrong? A breather valve not working? Simply overfill (I doubt, this has never happened before)? Any ideas??
I have a additional front mounted radiator, perhaps not flowing properly.......Thanks in advance
 
Jeff C. said:
Hello all, my first post. I changed gasket and filter for the TH350 and filled with correct amount . The level , after reaching temp, read low so I added maybe a half quart . Now , when I start after a couple/few weeks I get trans fluid burping out of the fill/level tube, about 1/8 qt or less, for a few seconds then stops. Aside from the mess, dripping on the exhaust manifold, etc, I wonder WHY???? Filter on wrong? A breather valve not working? Simply overfill (I doubt, this has never happened before)? Any ideas??
I have a additional front mounted radiator, perhaps not flowing properly.......Thanks in advance
Click to expand...
I always overfill my transmission by half a quarter for off road and never have this problem so it must be something else.
What? I can't think of anything right now but I'm sure someone will chime in here.
The only thing I can think of is that the dipstick is not correct and you have more than half a quarter extra.
 
Definitely check the vent to make sure it's clear, but in general, that's more of an issue once it's hot, not on start up. Chances are that fluid is draining from the torque converter and the cooler/lines as the transmission sits, so it's overfilled until the pump kicks in. I always recommend the dipsticks with the locking top.
 
Blue85 said:
Definitely check the vent to make sure it's clear, but in general, that's more of an issue once it's hot, not on start up. Chances are that fluid is draining from the torque converter and the cooler/lines as the transmission sits, so it's overfilled until the pump kicks in. I always recommend the dipsticks with the locking top.
Click to expand...
Thanks Blue85. I think I saw a vent up there somewhere. Where is it? Ok, I'll look into the locking dipstick too . Yeah, this never happened before and it's not pretty. Ha
 
Jeff C. said:
Thanks Blue85. I think I saw a vent up there somewhere. Where is it? Ok, I'll look into the locking dipstick too . Yeah, this never happened before and it's not pretty. Ha
Click to expand...
Yeah, my other Chevy has a locking dipstick.
 
I agree the after a week or two the torque converter drained back into the pan, I have seen the symptoms of torque converter drain back a few times, but not have it burp out the fill tube. Maybe after a long no use time disable the ignition and crank it over a few times before allowing it to start. What type of fuel system are you using ? what is the cold idle speed.

as for the external cooler, it can be plumbed wrong and trap an air bubble. Two ways will work. Inlet at the bottom and outlet at the top, and both inlet and out let at the top. you do not want them both on the bottom.

Also Welcome form out of the shadows @Jeff C.
 
Wes Harden said:
I agree the after a week or two the torque converter drained back into the pan, I have seen the symptoms of torque converter drain back a few times, but not have it burp out the fill tube. Maybe after a long no use time disable the ignition and crank it over a few times before allowing it to start. What type of fuel system are you using ? what is the cold idle speed.

as for the external cooler, it can be plumbed wrong and trap an air bubble. Two ways will work. Inlet at the bottom and outlet at the top, and both inlet and out let at the top. you do not want them both on the bottom.

Also Welcome form out of the shadows @Jeff C.
Click to expand...
Hello Wes, Thanks for the help. Mechanical stock fuel pump. The burp happens before the fuel arrives and worse once firing . All quick and stops......Idle , no tach, but easily above 1,000 till it settles. Then perhaps high but that's fine for turning on the AC
 
Jeff C. said:
Hello Wes, Thanks for the help. Mechanical stock fuel pump. The burp happens before the fuel arrives and worse once firing . All quick and stops......Idle , no tach, but easily above 1,000 till it settles. Then perhaps high but that's fine for turning on the AC
Click to expand...
Quadrajet, thermal
choke
 
yeah if it's happen with the cranking motor, that's seems odd to me.
Forgot, the vent is on top of the main case toward the front. A steel tube in the aluminum case. On 4x4 there will a rubber hose attached (should be) to keep water out when fording rivers
 
Wes Harden said:
yeah if it's happen with the cranking motor, that's seems odd to me.
Forgot, the vent is on top of the main case toward the front. A steel tube in the aluminum case. On 4x4 there will a rubber hose attached (should be) to keep water out when fording rivers
Click to expand...
Ok, it's 4x4 I'll check. Then, it could be only after it fires , have to look. I believe the external radiator is connected correctly....but will also check...I did disconnect and blow it out and reconnect so ....maybe
 
Jeff C. said:
Well, it's happened the last few start ups since changing filter etc. Haven't checked because didn't drive it to get it properly hot....
Click to expand...
Gotta go. Will check back this evening. Thank you
 
Hi Wes, attached is a trans cooler outing diagram. Mine is routed this way.
attached is a pic of the dip stick level....way high ...in the middle of the 'split'.....could be simply way too high at rest.
still need to check the vent, going out to do that now. I'll be away from my laptop till later....Thanks

Hmmm, can't figure out how to add pics from my downloads....
 
Jeff C. said:
Well, it's happened the last few start ups since changing filter etc. Haven't checked because didn't drive it to get it properly hot....
Click to expand...
Jeff C. said:
Hello Wes, Thanks for the help. Mechanical stock fuel pump. The burp happens before the fuel arrives and worse once firing . All quick and stops......Idle , no tach, but easily above 1,000 till it settles. Then perhaps high but that's fine for turning on the AC
Click to expand...
Yes inlet at the bottom and outlet at the top. So that's ok.
 
You only need 5 posts and then you can post pictures. You can use the picture icon at the top of the editor, drag and drop or cut and paste.
 
Blue85 said:
You only need 5 posts and then you can post pictures. You can use the picture icon at the top of the editor, drag and drop or cut and paste.
Click to expand...
I believe that's if he's a paying member.
I believe he's not.
He can link pictures unless the new version allows embedding without membership
 
imiceman44 said:
I believe that's if he's a paying member.
I believe he's not.
He can link pictures unless the new version allows embedding without membership
Click to expand...
Duly noted. I'll have to stop acting like I know stuff :whistle:
 
Go figure. After checking the oil cooler routing I tried a start without ignition. no burping......then with ignition...no burping....

And I haven't found a 'breather' on my '74 TH350
More will be revealed...???
 
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