rough shifting 4L60E

mnstrmdnss · January 14, 2002

i have a 98 sonoma 2wd with the 4L60E with just over 41,000 miles on it. is the tranny supposed to shift kinda rough? from time to time, it shifts rough only when shifting from 1st to 2nd, and when i 'floor it' form a stop, when it shifts into 2nd, the rear wheels spin when its wet out. all the local dealerships claim this is normal, saying that since its mated to a 4cly, the tranny shifts hard to help get some power out of the 4cly. im just wondering if anybody out there with the same setup has this problem or not.

January 15, 2002

I call B.S. on the dealer response. My brother-in-law's '94 1500 shifted pretty hard from 1-2 for about six months. Then second went out altogether. That is not normal.

mnstrmdnss · January 15, 2002

the shocker is, three dealerships have looked at it( cause its under an extended warrenty) and they all say the same thing. i need to get it to a tranny shop.

heres more of the scoop......i bought the truck used almost 2 years ago, it had 24000 miles. i know for a fact that the previous owner towed with it cause it has a 2" receiver hitch, and after i bought it, i had the shocks replaced cause they where leaking, i repalced the front rotors cause they where warped.

its been shifting hard since i bought it, so i repalced the tranny filter and some of the tranny fluid( i didnt flush all of it out, just replaced the stuff that was lost when i dropped the pan), and that didnt do anything. it doesnt do it all the time, doesnt have a 'set pattern', that is, when its cold, or hot, rolling starts or standing still starts, it just shifts rough out-of-the-blue, about 50% of the time. Im pretty sure somethings wrong, but you cant tell these dealerships that, cause according to them, we(the owner of our own vehicles) dont know anything! danm service deaprtment!,

hey, sorry to ramble on, but this has me flusterd and p.o.'ed

95Yukon · January 15, 2002

I do know this.. when I had mine apart, one of the checkballs was stuck in the hole in the valve body seperator plate from the hole being stretched out. It was shifting fine (I was putting in a shift kit) but I did fix that with a new plate. Also, there is a 1-2 shift accumulator (you can see the round piston shaped thing held on by 3 bolts with the pan off) which has a big effect on 1-2 shifts. Theres a piston in there which cushions the shift by letting the pressure of the fluid push onto the piston, which pushes on a spring. I have experimented with different spacers in there and it effects the shift in a big way. It is possible that piston is sticking sometimes, causing the 1-2 shift to be real hard when it sticks. I would get it to a transmission shop and get another opinion or have them check that out and whatever else could be wrong. Being electronic, it could be one of a million things causing it. I do notice mine shifts harder or softer depending on throttle position, but it should be consistent or something isn't working the way it should and could be the beginning of the end for that tranny if they cant find the problem.

(that piston is just a rount flat aluminum disk with an o-ring around the edge of it which sits on a centering pin) If you pull the pan you can get to it without pulling off the valve body. 3 bolts hold the housing on, then the piston is right inside it with a spring on the backside of the piston. If its working right, you should be able to compress the piston into the housing a little bit with your thumbs by squeezing it. If the spring is broken or the o ring seal torn or walls of the accumulator housing are scored, this could be whats causing the problem. Have a tranny shop check it all out and see what they find.

January 15, 2002

Ask the service people that are telling you this that you want to test drive a new similarly equipped truck.

That will settle it. Either they'll have to look at yours, or you eat a little crow.

mnstrmdnss · January 15, 2002

im having a few tranny shops look at it tomorrow, ill let you all know what b.s. they tell me!

tfpary · January 22, 2002

I agree with the yukon man... The 1-2 accumulator probably is at fault.

mnstrmdnss · January 23, 2002

ill keep your suggestions in mind when i get it looked at, right now im not worried about my truck for a while, cause me and my wife jsut had our second kid on the 20th, so i have a newborn to take care of for a while!!!!!