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Help Trans Hard Shift And Misfires


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Ok I didnt know what forum to put this in so here goes. My wife's colorado started to shift really hard going into second gear a couple of weeks ago. It shifts so hard that sometimes the low trac will flash on the instrument DIS and it will cut power to the rearend like it losing traction or something, but its not losing traction. Also the check engine light came on last week, and after a day or so magically went off. I read the code while it was on and it said cylinder 5 misfire.

So, I took the truck into the shop yesterday, and yea they say they felt the trans shift hard and they said that they hooked their computer up to it and read several cylinder misfires. They charged me $419 to flush the trans fluid and replace the filter (didnt know there was a filter in the transmission), put in a new fuel filter, and to do an injector flush and clean. They say that the misfires are gone and that the transmission shifts fine now when I talked with them yesterday afternoon. Although the truck does seem like its running better, the transmission is not perfect.

The really hard shift that it was doing is not all gone, it still does it some. I think I got ripped off. I don't understand why they didn't replace the spark plugs for one, and I don't understand how changing the fuel filter is going to help it stop misfiring! And I really don't understand how changing the trans fluid is going to help the shift IN ONE GEAR! I could see if all the gears were doing that, but one!!!

Someone please help me. Anyone have any idea why a transmission in the Colorado is shifting hard going into second gear? And do you guys think that I need to replace the plugs? Guess that I will have to do that myself. Please any advice! :dunno:

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You didn't get ripped off... Everything they did is right in line with what's going on with the transmission and misfires. The misfires most likely came on because the HUGE load increase during the extra hard shift. No need to replace the plugs unless the misfire comes back unless it's time for a tuneup.


How many miles are on the Colorado? I ask because you said that you didn't know there was a transmission filter, which means you must have never had the transmission serviced before... You need to do that every 45,000-60,000 miles depending on your driving habits. Gummed up fluid passages in the trans can CERTAINLY effect one gear over another because each gear has their own passage to engage each individual gear.


Another item is that GM transmissions related to the 700/4l60/65/70 all seem to develop a hard 1-2 shift, studder shifts, or lose shifts all together. If this trans still doesn't feel right, it's time to start thinking about getting rid of it... or rebuild the trans could be in your future.

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boon thanks so much man, there are 70,000 miles on the truck exactly. And no I have never had the trans serviced in that truck before. I dont know jack squat about transmissions. But that truck has never pulled anything, and has always been babied, I mean my wife drives it. I have probably put my SS trans through more than she has that colorado. Dang I hope it doesnt need a rebuild.

But about the misfires...this is not the first time I have read the code. I read it about 20,000 miles ago and the check engine light went off then too, so I didn't think anything of it. So I am thinking about changing the plugs just for routine maint now.

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It's not all about abuse, sometimes neglect on service items is just as bad or worse on a vehicle. Typical women drivers drive in town in heavy stop and go traffic and that shortens the change intervals on almost all maintenance items. Time to crack open the oweners manual and see what else you are due for changing, probably some gear lube, full chassis lube, belt, radiator flush, etc all usually come due on or about 60,000 miles.

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