My '00 Silverado is afraid of overdrive.

[CN Spots]

Truck started acting strange a few weeks ago. It acts like it dosen't want to shift into overdrive as easily as it used to. It kinda stutters until I press the pedal a little more before it finally shifts. Sometimes it goes down two gears, fabulous fun in the rain. 30 years ago I'd suspect a modulator valve, these days I probably need to reboot my torque converter. 200k miles. No clanking or grinding. Haven't checked for shrapnel in the pan yet. Thoughts?

Thanks,
spots

 

[CVX20SPRINT]

Re: My '00 Silverado is afraid of overdrive.

I did tranny's for a GM dealer for 15 years and if there is one thing I know it is there is no cheap way to fix it.If it has slipped at all it should have turned MIL(check engine,service engine soon)light on and stored a powertrain code.If it were mine I would get it checked for codes and go from there,but I would think with that amount of miles you would be looking at a rebuild.If in doubt pull the pan off and take out the filter.Open up the filter and it will probably have a fair amount of clutch material in it as well as some metal particles.If you find much of either you're in for a build.

 

[dolluper]

Re: My '00 Silverado is afraid of overdrive.

Quick little test....put it in tow mode switch on end of gear selector...run it threw all shift points then stop switch back to normal mode ...go threw all shift points again ...same problem ....get the trannie filter and fuild changed at least.....what colour is your fuild now anyways ...does it smell burnt along with a brown colour if black ...rebuilt time

 

[windsors03cobra]

Re: My '00 Silverado is afraid of overdrive.

Yea you will never go wrong dropping the pan and changing the fluid.
Your going to see how much sludge is in there which gives you a little idear on whats going on in there, you can also get some fresh fluid it in and also check for piece parts in the pan which are never a good sign.
Lot of miles on that trans but I have also seen them at 300k and still working fine, some die at 80-100k tho as well so ya just never know

How often have you changed the fluid ? You put all 200k on er ?

I also appreciated the older simpler trans tho my preferred trans were TV cable regulated overdrives.

 

[CVX20SPRINT]

Re: My '00 Silverado is afraid of overdrive.

Like I said I would check for codes before doing anything other than checking the cond. of the fluid.There is nothing in that trans that can go bad without storing a code(most places do this for free).Also you will probably see a fair bit of sludge in the pan if it hasn't been serviced recently.Some of this aluminum mud is normal but there should be no hard chunks of any size.Don't forget to check the inside of the filter as it will catch a lot of crap before the trans actually fails.

 

[CN Spots]

Re: My '00 Silverado is afraid of overdrive.

The tow mode trick didn't show any change.

The PO took very good care of her. Dealer serviced everything. It's been over 50k since last change so it's overdue.

I'll take it by NAPA or the 'Zone tonight and have them pull the codes.

Thanks!

 

[waterinthefuel]

Re: My '00 Silverado is afraid of overdrive.

Just a bit of FYI harbor freight has obd ii code readers on sale sometimes. My dad got the newest one a few months ago for like 21 bucks. It's normally 59.99, was on sale for 29.99 and I had a coupon for like 20% off. That same one hasn't dropped below 40 bucks since that day.

It works great and uses the cars computer for power so it doesn't require batteries. It can also clear any codes you may have.

 

[86 century]

Re: My '00 Silverado is afraid of overdrive.

Sound like a tcc shutter the control for the lockup converter is going goofy. My '99 gmc has done this for 50k on and off and has not fell apart yet.

 

[CN Spots]

Re: My '00 Silverado is afraid of overdrive.

Well, NAPA doesn't do codes and Autozone said that there were no codes showing when they checked. New fluid is my next step.

Any opinion on flushing vs fluid/filter change?

 

[ezmobee]

Re: My '00 Silverado is afraid of overdrive.

For your circumstance....I 100% recommend dropping the pan and changing the filter. I was having some slippage issues with my old '90 K1500 last year and a filter change cured it. I had previously had a flush done.

 

[windsors03cobra]

Re: My '00 Silverado is afraid of overdrive.

I would start cheap just dropping the pan and changing the filter and while I'm sure any trans flush place would/could drop the pan and change the filter and check the pan for metal shavings and observe the sludge there is no real reason to spend $80 or $100 on a flush.

 

[Stachi]

Re: My '00 Silverado is afraid of overdrive.

Truck started acting strange a few weeks ago. It acts like it dosen't want to shift into overdrive as easily as it used to. It kinda stutters until I press the pedal a little more before it finally shifts. Sometimes it goes down two gears, fabulous fun in the rain. 30 years ago I'd suspect a modulator valve, these days I probably need to reboot my torque converter. 200k miles. No clanking or grinding. Haven't checked for shrapnel in the pan yet. Thoughts?

Thanks,
spots

sounds like a valve body prob...with that amount of miles on it...trans ever been serviced? (pan down, filter changed) may need to drop the valve body and work the valves ...sounds like one or two are sticking (working the gas pedal) let usknow

 

[Stachi]

Re: My '00 Silverado is afraid of overdrive.

Well, NAPA doesn't do codes and Autozone said that there were no codes showing when they checked. New fluid is my next step.

Any opinion on flushing vs fluid/filter change?[/QUOTE

the only way to remove ALL of the transmission fluid from a trans...is to tear it all the way down and rebuild it. I am not impressed with the flushing theory...I do not believe just dropping the pan and replacing the filter is enough either...but it seems to work well enough ....my best bet ,flush , then drop the pan & replace filter...the flushing ( done with engine running and shifting gears) will help clean the drums and passages)...now replace filter ............

 

[itsaboattime]

Re: My '00 Silverado is afraid of overdrive.

Truck started acting strange a few weeks ago. It acts like it dosen't want to shift into overdrive as easily as it used to. It kinda stutters until I press the pedal a little more before it finally shifts. Sometimes it goes down two gears, fabulous fun in the rain. 30 years ago I'd suspect a modulator valve, these days I probably need to reboot my torque converter. 200k miles. No clanking or grinding. Haven't checked for shrapnel in the pan yet. Thoughts?

Thanks,
spots

Don't know if this would apply, heck I don't know if they even work the same. My old ford did the same kinda thing. I couldn't get it to shift into overdrive, and when it did I lost power and speed. I had to drive it out of overdrive. I found the hard way that I had a clogged catalytic converter. I at first thought it was a trans problem, but my fluid was clean and didn't smell burnt. I did change the fluid and filter.
It turned out that I had exhaust troubles.......wasn't the trans at all.

Like I said, this may not apply to your Chevy, but I just thought I'd throw it out there.

 

[Stachi]

Re: My '00 Silverado is afraid of overdrive.

Don't know if this would apply, heck I don't know if they even work the same. My old ford did the same kinda thing. I couldn't get it to shift into overdrive, and when it did I lost power and speed. I had to drive it out of overdrive. I found the hard way that I had a clogged catalytic converter. I at first thought it was a trans problem, but my fluid was clean and didn't smell burnt. I did change the fluid and filter.
It turned out that I had exhaust troubles.......wasn't the trans at all.

Like I said, this may not apply to your Chevy, but I just thought I'd throw it out there.

this may well be the cause...I have seen it on many cars of different manufacturers...let us know what you find...

 

[dan t.]

Re: My '00 Silverado is afraid of overdrive.

ok this is my advice,I have been rebuilding trannys for the last 30 years and if a customer came in with the same symptoms this is what I would do
# 1 scan and road test,correct any electrical faults
#2 drop the pan,check the filter and the magnet, if the magnet looks like a porkupine she is done ,if relitivly clean there is hope.
#3 replace the filter and pan,clean the magnet
#4 add 4 or 5 quarts of oil, disconect the return cooler line attach a hose and lead it into a bucket,start the truck and continue pouring oil in the filler untilyou have pumped 10 quarts thru.
#5 hook up the cooler line, you have now flushed the torque converter.
#6 add 1 bottle of Lubegard and top up the oil to the proper level
good luck

 

[CN Spots]

Re: My '00 Silverado is afraid of overdrive.

I took it in to have it flushed Saturday, they looked at the fluid and the mileage and advised against it. Said it would cause more problems that it would fix. I thanked him for his honesty and left.

I changed the fluid and filter myself. The magnet only had some metal clay (very fine powder) on it and there were no chunks to be found. The fluid was on the south side of red, closer to brown. Ruh-roh.

There has been no change in it's behavior since the fluid change. Same old probs.

I have a bottle of Lucas Transmission Fix that I'll probably try next. I know you can't "fix" anything with with it but maybe it'll buy me a few more months to save up for rebuilt tranny.

Thanks for all the help!

spots

 

[NYBo]

Re: My '00 Silverado is afraid of overdrive.

Well, NAPA doesn't do codes and Autozone said that there were no codes showing when they checked.

A standard OBD II code reader won't read transmission codes (except a generic code if the transmission fault trips the MIL).

 

[j_martin]

Re: My '00 Silverado is afraid of overdrive.

A standard OBD II code reader won't read transmission codes (except a generic code if the transmission fault trips the MIL).

I just had a dodge caravan start acting real goofy like that. It threw a code, but didn't set the check engine light. It was the high speed sensor on the transmission. 16 bucks and some scun knuckles and it's good to go.

If there isn't a mechanical throttle linkage to it, then the throttle position sensor could cause that trouble also.

 

[CN Spots]

Re: My '00 Silverado is afraid of overdrive.

Called a local trans repair shop last night to get a quote on a replacement. They said to bring it in and they'd check it out for free. "Might be one of a thousand things, might be ALL of a thousand things." After hearing all of the things that it could be, I figure having them look at (for free) it is not a bad idea. I'll try to get it by there this weekend or Monday.