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**COBALT** · 01-31-2003, 07:23 PM

What they're telling you doesn't sound quite right. What do they mean by "drainback"? Where would you put a 1-way check valve, and what would the purpose be in connection with the torque converter? Sounds like BS to me. If they're planning on putting a 1-way check valve in you valve body I'd like to know WHERE they plan on putting it.

What does sound like your problem is a bad front pump. It sounds like it's taking too long to build up enough case pressure to change the main valve actuator from P to D or R. Remember that fluid pressure makes any part of your transmission work, and if you don't have the right fluid pressure no shifting will take place.

Once it starts to shift ok, can you basically shift back and forth between D and R just fine (more than once in other words)? Is there any slippage in R? Any slippage in D? This may also be caused by excessive slip on your apply band (what helps engage R), or your friction plates, but you'd feel slippage after it engaged, but it doesn't sound like it's engaging at all.

Simple things you can do are:

1. Check transmission fluid at OPERATING temperature. Fire up the truck, and let it warm up, then move the selector through all gears, throw it in park and check the fluid. Is it full? Is there any maroon sludge on the stick?

2. Drop the pan and see what's in it. Any broken lip seals or pieces of debris?

01-31-2003, 07:23 PM	#3
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	What they're telling you doesn't sound quite right. What do they mean by "drainback"? Where would you put a 1-way check valve, and what would the purpose be in connection with the torque converter? Sounds like BS to me. If they're planning on putting a 1-way check valve in you valve body I'd like to know WHERE they plan on putting it. What does sound like your problem is a bad front pump. It sounds like it's taking too long to build up enough case pressure to change the main valve actuator from P to D or R. Remember that fluid pressure makes any part of your transmission work, and if you don't have the right fluid pressure no shifting will take place. Once it starts to shift ok, can you basically shift back and forth between D and R just fine (more than once in other words)? Is there any slippage in R? Any slippage in D? This may also be caused by excessive slip on your apply band (what helps engage R), or your friction plates, but you'd feel slippage after it engaged, but it doesn't sound like it's engaging at all. Simple things you can do are: 1. Check transmission fluid at OPERATING temperature. Fire up the truck, and let it warm up, then move the selector through all gears, throw it in park and check the fluid. Is it full? Is there any maroon sludge on the stick? 2. Drop the pan and see what's in it. Any broken lip seals or pieces of debris? __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.