Changed Tranny Fluid, something got messed up.

[Unofficial]

So today I did some work to my truck. I tightened up my valve covers where oil was leaking, I fixed my oil pressure sending unit, plugged up what I thought was a vaccum leak, and changed my tranny fluid, filter, gasket, and pan. I had a hissing noise, so I looked at all of my main vacuum lines and found nothing. I plugged something on my MAP sensor, trying anything to fix my hissing. I changed my tranny pan on my 700R4, and after I put on the deep dish pan and filled it up, my truck won't shift right. It won't leave first gear and it almost feels like I'm in neutral once I get up to speed. Does anybody have any idea what could be going on? I'm hoping I didn't bump anything in the tranny when I was changing the pan.

[VileZambonie]

Drop the pan and make sure the filter is installed.

[nyamwegi]

I'm pretty new to the chevy truck scene (except for an '01 I had that was a manual), but I came to hate automatics as they were always going out on me. I have been told from more than one source that changing the fluid in an automatic transmission that has had the same fluid for a long time will cause problems. Apparently the new fluid has "detergents" in it that can mess up the amounts of friction necessary, etc. inside an automatic. I'm sure there's guys on here that no more about it than me but I've heard that.

[Unofficial]

I dropped the pan again, and the filter wasn't in all the way. When I took the pan off, the filter was in the pan. I got the filter in right, it just had to go into the hole a little bit more. So I got the pan back on, and I have the same problem. It won't leave first gear.

[VileZambonie]

did you mess with the TV cable? Pop the governor cover off and remove the governor. Check the gear and make sure it isn't apple cored.

[eventhorizon66]

If you put a stock filter on a deep pan chances it is too high in the pan and as a result your pump is losing pressure when it occasionally sucks air.  You need a filter extension to drop its installed location to proper position.  Check with the pan manufacturer.  A stock filter in a stock pan has no room to fall out.

[okuma]

unofficial , you are correct ... it is the oil change that affected this shifting problem. I have had the same problem before on a F--d .

do you still have the old oil removed from the tranny?  if so you will ''need to" repace it back on the tranny.  hopefully you catched all the oil on a clean container.!

[Unofficial]

unofficial , you are correct ... it is the oil change that affected this shifting problem. I have had the same problem before on a F--d .

do you still have the old oil removed from the tranny?  if so you will ''need to" repace it back on the tranny.  hopefully you catched all the oil on a clean container.!

No, the fluid is gone. The reason I changed it is because when I would accelerate and then let off the gas, my truck would whine. I asked on here and got the idea that the old fluid went bad and it aerated when it went through the transmission pump causing it to whine. So my truck isn't going to shift because I got new fluid? That sucks. 

[VileZambonie]

It wouldn't move if it was the pump. You don't need to put the old fluid back in it. If it just won't upshift, check the governor like I said if the fluid level is correct and the filter is installed correctly at this point.

[Unofficial]

Well I yanked at my TV cable at the TB a couple times thinking maybe it was locked up somewhere. It didn't help much, but I noticed that my truck does shift, but not until about 4,000 RPMs. My dad knows a guy who has owned a transmission shop since 1984, so we just dropped it off there. The guy is going to check the filter to see if I need an extension, and he's going to check my throttle valve cable and narrow it down to the problem so he can fix it.  Thanks for the help guys.

[Unofficial]

I got a phone call from the shop. I guess my valve body was locked up where one of the moving cylinders were. They bored it out and put a different part in. That power loss/stumbling I would get was caused from this, and it shifts better than ever. They also replaced my transmission lines because they were really rusty. I'm going to pick it up to take it home tomorrow. Everything was around $500.

[82K10WI]

Sounds good. its always nice to have another chevy on the road around here. well my truck will put away soon. and out come the fun runner.

[Unofficial]

Sounds good. its always nice to have another chevy on the road around here. well my truck will put away soon. and out come the fun runner.

Why would your truck be going anywhere? It looks like it's got years and years to go!

[82K10WI]

my truck doesnt run in the wisconsin salt season. lol i saw snow last sunday and i think nature is telling me to put it up for the year. well more than just this winter more like almost two years. ill get out the other truck for the winter. then i go overseas in early next year so ill miss my baby.