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Turbo 350 tranny

 
opie1163millwright
I love my Chevy Chevette!
Posts: 2
Joined: 01/11
Posted: 01/26/11 05:04 PM

after buying a el camino with a rebuilt mild 355 and a rebuilt turbo 350 the tranny started overflowing fluid out the dipstick if the car is stopped hard then slips for a few seconds before catching.  The tranny shifts well but takes a long time going into drive or switching to reverse. It has a throttle position cable, vaccum modulator is hooked up and i've tried changing  fluid levels. There is no slippage in gear under power but tranny runs 250 degrees according to gauge after warmed up. I can see a 10 inch converter that stalls 2000rpm well.  Where do i look to start?
I ve tried fluid level changes from full line at operating temp, to barely on the dipstick at operating temp and tranny still overflows, obviously the lower the fluid the longer it takes to go into gear, and i have a huge cooler that is not blocked and lines are not kinked.  Someone has said about the pump to me causing the problem, should i tear it apart and what would i look for?  

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chevelle83
I mow my lawn and find Chevys
Posts: 2280
Joined: 11/09
Posted: 01/27/11 12:10 PM

auto trannys are very difficult to diagnose without tearing into them.

250 degrees is not extreme but do you have an external oil cooler?  

are you sure the dipstick is the correct length?? I wonder if you may be overfilling the trans??  Most of the time if the trans is overfilled it can overflow out of the vent on top of the trans before it comes out of the dipstick tube.
 I wonder if your vent could be clogged??

 have you tried adjusting the modulator?  
remove the vacuum line and use a small flat head screw driver to turn the adjusting screw counter clock wise to lower the shift points I would start with 2 full rounds and drive and see what that does.

 the modulator only affects part throttle shifts.

does this happen in all gears??  

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redneckjoe69
I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 01/27/11 12:38 PM

i was kinda wondering about the clogged vent too, but did'nt know if it would cause fluid to go up the dipstick tube or not.    so i kept my mouth shut. lol.   Grin  

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opie1163millwright
I love my Chevy Chevette!
Posts: 2
Joined: 01/11
Posted: 01/27/11 01:23 PM

Only happens at hard complete stops in 3rd. modulator looks new and i ran a new line to it but never touched it. I did try different levels of fluid with no change. The car has a large cooler. I like the vent idea does it just pull out?  

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chevelle83
I mow my lawn and find Chevys
Posts: 2280
Joined: 11/09
Posted: 01/27/11 04:38 PM

I have never herd of fluid coming out of the dipstick before,,,,

 I have tortured thm350 until they all but caught on fire,,,,, but yet they never puked out the tube.  fluid usually overflowed the vent.

I had one so hot in a 4x4 truck one time that the fluid sizzeled and stuck to the case, and most all the internals were welded together, the only thing still useable was the case itself.

are you using the factory dipstick tube  

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redneckjoe69
I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 01/27/11 06:36 PM

are you checking it hot & in park on level ground?   pretty weird problem.   Confused  

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