NEED HELP 2002 TB transmission having a hard time to shift trough gears


Active Member
Hello All,
this is my second seek for help post in here, 1st was fuel pump relay blowing off fuse 28 pcm1

you can see it here
thanks to mooseman and all the crew who helped me a lot !!

ok so i am the third owner of a this 2002 TB LS, only 110K miles on it,
but the tranny is start to act up, most of the time the problem starts with a cool engine on the mornings

The symptom is: delayed hard shifting from 1st gear to 2nd gear, then sometime it refuse to switch to 3rd gear
so i canot rev up more than 3k RPM's and that its about 33MPH speed, but after a couple of minutes
it starts to shift normal trough all the 4 gears

as a side notes, when stooping on a red light it shifts down perfect, problem is up shifting not downshifting ,the fluid level is normal

i read somewhere that maybe the solenoids are giving up, so to add a quart of TRANSX additive, and if the problem do not go in 2 days, you need to overhaul the tranny.

so if you guys think i need to add the transX thing, how do i remove a quart of fluid from the tranny?

also, can i do a filter change and pan clean along with the magnet on the pan who attracts all the worn out metal
debri, i saw a you tube video and like black gunk

Fluid is Dexroon III or VI (synthetic)
what do you guys recommend to do at this point

Oh, i forgto to add, when i experience the hard shift problem, i hear a heavy fan ( radiator ) roar like if the fan clutch its stuck and the fan rotates at higher rpm, the more i RPM the engine the more the fan roar, then after a couple of minutes it goes to silent operation, i do not know if one thing is linked to the other, or is just coincidence, but murphy law says that says "whatever can go wrong, will go wrong. " :crazy:

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Well-Known Member
I'm by no means a transmission expert, but mine does have a slight "hard" shift from 1st to 2nd when it hasn't fully warmed up. No idea why, but the last 3 trucks Envoys/Trailblazers I've owned have had this characteristic.

A couple things you could try doing which I don't see too much harm in, is replacing the two shift solenoids ($9-10 bucks on Amazon), or the Torque Converter. Since you'll be in the tranny, won't hurt to give it some fresh fluid and a new filter. That's just my take on it, I'm sure someone else who is more familiar with how these things work can chime in with more troubleshooting tips/suggestions. :smile:


Active Member
Hey Mike,
that is nice advice, but the torque converter is around 120

a re-manufactured 4L60 tranny ranges from 1,100 to 1500 depending where you buy it,i was looking at some online shops that offers overhauled 4L60's , thing is i dont the special tools to ovehaul a 4L60 completely by myself , but maybe as you do said, changing filter and fluid, cleaning the pan magnet and changing the solenoids must do the trick , i have a question, doesn't the solenoids just stop working completely when gone bad ?? or they just work with a delay ? , to my knowledge electromecanical parts just work or stop working, and do not behave intermittently
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Well-Known Member
Typically it'll set off a code I'd the solenoids are bad, or some sort of delayed shifting. When the 3rd to 4th solenoid went bad in my Trailblazer it set off a CEL, and it wouldn't shift out of 2nd while in "Drive". I also had an odd delay when it was trying to go from 2nd to 3rd before it fully went out. Whenever I change the fluids/filter I make it a habit to just change them out because of how cheap they are.

I just suggested the convertor since that and the servo change + the transgo shift kit seem to help eliminate the weirdness/issues these transmissions have.


I would try a pan drop, inspection, clean and replace filter and fluid. Dex VI is pretty much the only thing available since DexIII has been dropped by GM a few years now. There's also Valvoline Trans Max that says it's compatible with Dex VI but isn't "approved" or licensed by GM to use that designation.

If the fluid is old and the filter clogged, it can cause poor shifting. Someone else had a similar issue and was solved by a fluid and filter change. If the fluid is really old, you should do a Transmission Fluid Exchange (Flush) .


Well-Known Member
When was the last time you changed the transmission fluid?

I would drop the pan and change the fluid and filter. Make sure you get the correct one, they have two versions, one for the deep pan and one for the shallow pan. And inspect what you pull out. Personally I would not flush it, just too many anecdotal stories about flushing old transmissions causing problems. (most likely from trannies that had a problem though)

If that doesn't work, you can pull off the valve body and clean and inspect that as well, you might see something. That gets a little more adventurous however.

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