ANY CHEVROLET MECHANICS?

cobra44

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Hello
I have a 2003 Chevy Impala with the 3.8 engine.
It has been a good car. It has 128,000 miles on it.
Today it started not shifting through all the gears. If you shift it manually, it is alright about 50 % of the time. Reverse works alright, along with low gear.
If you just leave it in drive 2, it will move some of the time.
I hope that it is something simple.
Any input would be appreciated.
 
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It is possible a fluid and filter change will help. If it were mine, I'd also drop the valve body and clean up all the spool valves, those are probably sticking from debris in them.

The new generation auto trannys run real tight clearance compared to the turbo 350 era trannys. Even a few arm hairs in the valve body of these newer ones will trip them up.
 
+1 on the fluid and filter change. Not too hard to do yourself and not too expensive. But be prepared to get really dirty. Wear old clothes. Oh, buy a Chilton's or Haynes auto repair manual.
 
Thanks for the replies.
I will check it out tomorrow. I have a repair manual for it.
I hope that that is all that is wrong.
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You'll likely find the filter full of clutch pack/band dirt. Symptoms of the like are usually worse in the AM on cold starts. Your wise to not drive it any further than necessary before servicing. While never robust, the newer units are even more fragile. As was noted above, the valve body may have become contaminated too?
Good Luck!
 
When you replace the fluid, add a quart of Lucas Automatic Transmission additive. I've been nursing my Mercury Sable along for 100k miles on that stuff. Also, if GM calls for any synthetic fluid (Ford says 50/50), use ALL synthetic fluid. Transmissions are running at hotter temps these days, so it's easy to scorch the regular stuff.
 
Just a trivia question Truck.
Do you know part of ther reason synthetic fluids had to be employed?
Answer-
Automatic transmission fluid used to have a whale oil component. Which could not be duplicated via mineral oil, once Whale oil was treatied out of use.
 
I knew posi-traction additive had whale oil but I do not believe trans fluid ever had whale oil. I have over 20 years restoreing autos.

GM did not go to synthetics till 2006 with Dexron 6. And Dexron 6 is backwards compatable with all older transmissions.
 
Originally posted by Spotteddog:
Just a trivia question Truck.
Do you know part of ther reason synthetic fluids had to be employed?
Answer-
Automatic transmission fluid used to have a whale oil component. Which could not be duplicated via mineral oil, once Whale oil was treatied out of use.

Jeep used to sell the whale oil in 2 ounce bottles for use in their quadratrac transfer cases. When they stopped using it, they started to suffer premature failures of the chain assemblies due to wear.

I should have saved a few of those little bottles.
 
Yup,
The GM posi additive was fish oil (for the 70's era housed D & D limited slips) I wasn't aware of the Whale oil portion? Nor of it being in the transfer case treatment either? The heavy research into all of the synthetics began due to the Whale oil being pulled out of the automotive fluid(s). When it got to the point that even the 727 TorqueFlite's started having trouble with out it! Don't forget, that was at the point where no two cars seemed to use the same fluid! I'm sure that not only is the stuff better now than it ever was, but also the units are less forgiving and more fragile due to their complexity. (Locking convertors etc.)
(EDIT) BTW- Never was a Chevrolet mechanic. Did Dodge, Chrysler/Plymouth and Pontiac.
 
If you've never had the trans fluid changed I'd recommend you take it to a shop that will pressure flush the trans. When done without a pressure flush only about 1/3 of the fluid actually gets changed as 2/3's of the fluid is in the torque converter. You could "pressure" flush it yourself but it's very easy to damage the trans if your not experienced.
I take the return line from the trans cooler and put it in a bucket. I start pouring fresh fluid into the filler tube while someone starts the motor. I use a 1 gallon container of fresh fluid, because you don't want to run the pump when it's dry, which could happen while your grabbing the next quart container and the pump in pumping old fluid out. I continue until I see fresh fluid coming out the return line. If it's been more than 40K miles since the last fluid change, your overdue.
 
You'll be lucky if just a fluid and filter change remedies your problem. Your symptoms seem to indicate a bigger problem BUT at this point it's worth a shot.
 
I agree sounds worse than a filter fluid but it could be a trans sensor if it were in my shop we would scan it to see what codes are in it and go from there.
Also pull the dipstick and see what the fluid looks like ,if its black and smells burnt not good
 
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