03 hard shift 1-2 4l60

[Timc9516]

Ok so I bought the truck last year in March and I knew it had a slight hard shift on 1-2

Well I've finally gotten around to trying to improve the truck alittle. I cleaned the maf sensor with no change so I'm thinking about trying a new tps sensor considering it's cheap and I don't have to open the trans

Buy my question is what would you recommend next.

The truck has 163k on it and I don't have any record of the trans being serviced. Would you recommend replacing the 1-2 accumulator and doing filter and fluid replacement or doing the accumulator and not changing filter but changing fluid or leave it till it blows up and rebuild the trans?

 

[Mudsport96]

No check engine light? How does it shift and drive in the other gears? Does it shift hard no matter how much throttle you give it or just at full throttle?
My Silverado has a hard 1-2 shift above approximately 60 percent throttle. It has a new transmission with less than 5000 miles on it. But it did it with the old transmission too. The tps maf all check out, so it's in the programming im guessing.

 

[Rocket Man]

How hard of a shift is it? I’m thinking if it’s just firmer than normal, the 1-2 servo might have been replaced with the corvette servo which is a popular mod. Another thing I know from experience that can cause an extremely hard 1-2 shift is if the trans was serviced and RTV was used on the pan gasket, it can clog the servo passages which are right at the pan rail. If this happens, the servos don’t release properly and the super hard shift happens. If I was you, I would drop the pan and replace the filter and do a fluid swap regardless. It’s basic maintenance that needs to be done plus you can check for the issue I mentioned. I highly recommend a LubeLocker pan gasket. And no RTV lol.

 

[Timc9516]

No check engine lights except occasionally when I had to floor it to get up to high way speed (my town is stupid and messed up the on ramp during construction) it would blink. But it was always a random misfire code. I plan on doin plugs and wires soon.

As for driving and shifting in other gears. Its fantastic. You would never know it has 163k on it. 2-3 is alittle weird but I think it's just compensating for 1-2.

As for throttle input its kinda hard to answer my fiance says she thinks it me and that it doesn't do it to her but I've never been in the truck with her to confirm that. However I have noticed every so often it doesn't do it. For example one time I took off from a stop sign and it didn't shift hard but then when I took off from the next stop sign not even a 1/4 mile down the road it shifted hard.

As for how hard of a shift it is. It's definitely not normal. Everyone who has been in the truck has commented on it.

I'm bringing the truck into my work to do front brakes and a wheel bearing this Saturday. I will definitely crawl underneath to check if the pan has rtv around the edges.

So your saying even tho I don't know the history on the trans I should service it anyways? Sorry for being so cautious my last truck was a ram 1500 and I had a code for a solenoid around 140k I did the solenoid, filter, and fluid and it made it a week and then blew up

 

[Rocket Man]

A fluid swap and filter change has never been an issue afaik. The problem usually arises from a flush on an old trans, that’s where the stuff gets stirred up and pushed throughout due to using a machine. Just replace whatever comes out when you drop the pan, usually 6-8 quarts. This is the advice I’ve always heard.

 

[Tonyrodz]

Mine shifts so hard during the 1-2 shift that the tires chirp, but I do have the vette servo.

 

[Rocket Man]

Mine shifts so hard during the 1-2 shift that the tires chirp, but I do have the vette servo.

Mine shifted so hard it twisted the output shaft in two.

 

[Tonyrodz]

Mine shifted so hard it twisted the output shaft in two.

In reverse . Btw--Hoe was running PHENOMENAL today! For once lol.

 

[Rocket Man]

In reverse . Btw--Hoe was running PHENOMENAL today! For once lol.

No, in reverse I twisted the front diff in two. Separate incident.

 

[Tonyrodz]

No, in reverse I twisted the front diff in two. Separate incident.

Ahh, nice! Impressive.

 

[BentleyArnage]

No check engine light? How does it shift and drive in the other gears? Does it shift hard no matter how much throttle you give it or just at full throttle?
My Silverado has a hard 1-2 shift above approximately 60 percent throttle. It has a new transmission with less than 5000 miles on it. But it did it with the old transmission too. The tps maf all check out, so it's in the programming im guessing.

It's likely that the accumulator is suffering from a broken spring. I'll agree with the possibility of silicone in the relief hole at the pan gasket. I'm getting the same thing you're getting. I'm putting a Transgo HD-2 shift kit in the trans. I love them for towing and the converter lockup won't take a shit from the worn valve. Big chevy problem.

 

[Timc9516]

So I was doing some more research and apparently I have a 4l65e not a 4l60e. Does that change the diagnosis of a 1-2 accumulator

If not then is there a difference between the accumulator in the 4l60e and the one in a 4l65e

 

[MOHAMMED AFANAH]

hope somone knows the answer . hard shift from 1st to 2nd . only after driving the car for about 10 or 15 min . note that ive bought and installed 4L60E transmission rebuild kit . also bought a new valve body with new solenoids. and a new tps sensor and problem still exsists . i dont know where else to look now .

 

[rockola1971]

A 4l65e is just an upgraded 4l60e. Your 1-2 accumulator spring is busted in half. Stereotypical find of a 4L series transmission that has never been opened up. Possibly a check ball peened into its seat on the seperator plate also. Both are the norm of a worn tranny. Pull the pan to see the busted accumulator spring.

 

[Timc9516]

Hopefully I'll get a reply on this old thread

Well I went and ordered a new 1-2 accumulator from gm and the sonnax pinless accumulator. I got them in today and when I pushed the plastic piston out to install the new one I found the accumulator only came with the small spring. Every video I have watched on this shows 2 springs in the accumulator 1 small one and 1 big one that sits around the small one. Did I get ******* here or am I just watching the wrong videos? Any help would be appreciated I just want to make sure I have all my parts before I drop the pan

 

[Mudsport96]

Hopefully I'll get a reply on this old thread

Well I went and ordered a new 1-2 accumulator from gm and the sonnax pinless accumulator. I got them in today and when I pushed the plastic piston out to install the new one I found the accumulator only came with the small spring. Every video I have watched on this shows 2 springs in the accumulator 1 small one and 1 big one that sits around the small one. Did I get ******* here or am I just watching the wrong videos? Any help would be appreciated I just want to make sure I have all my parts before I drop the pan

Post a picture of what you have parts wise.

 

[Timc9516]

Post a picture of what you have parts wise.

Everything is brand new. I haven't dropped the pan because I only have one vehicle and can't be stuck waiting for parts

 

[Mudsport96]

Did your parts come with instructions? Perhaps the pinless piston takes up too much room for the second spring.

 

[Timc9516]

No instructions unfortunately. But I bought them separately so as far as the accumulator it should be what ever stock should be. I'm just not entirely sure what stock for an 04 yukon xl denali with the 4l65e is

 

[Mudsport96]

So you ordered a whole new accumulator housing from GM and only got one spring? I would just order the big outer one if you are worried about harsh shifts. Me, id roll the dice and hope the one in my trans was ok. Then again i like solid shifts, so even if it was broken id probably just hit up a hardware store and look for a spring close in diameter. Just to keep tension on the piston not even really for cushion.