2004 Rough shifts in first and second

[3echo9]

First off..I didn't change the CV joints to fix the rough shifts but rather because I had a torn CV boot but after the job the rough shifts disappeared.

Anyway, after I replaced the CV joints and later took the car to a IT shop for a $20 transmission fluid change per coupon. The shop found a broken front left hydraulic mount and $200 later I'm out the door. The $200 included a $20 filter which wasn't included in the coupon.

Three days later the car sometimes shifts hard in first and second gears when accelerating.

BTW: No codes.

Question: could bad plugs and wires cause these symptoms as I have read in some other posts?

[Tech II]

Did you actually check for codes? There are some tranny codes that don't turn on the CE light.....if set they cause full line pressure, which can cause harsh shifts....

[3echo9]

Originally Posted by Tech II

Did you actually check for codes? There are some tranny codes that don't turn on the CE light.....if set they cause full line pressure, which can cause harsh shifts....

No, I personally did not check for codes but the transmission shop said they did and didn't identify any.

Another clue perhaps...I only notice it acting up after the car is warm.

[HotZ28]

Any previous fluid/filter changes? Was Dexron VI fluid used?

[3echo9]

Originally Posted by HotZ28

Any previous fluid/filter changes? Was Dexron VI fluid used?

The bill from the Independent Transmission shop did not itemize the type of fluid used on the refill. Is there a way to visually tell whether it is Dexron VI?

And based on the color of the fluid when I changed the CV joints (dark brown) I would say this was the first time the T-fluid had been changed. I've only owned the car since June this year. I wish I would have checked the fluid level before dropping it off for servicing. I didn't lose hardly any fluid when I changed the CV axles.

[imidazol97]

Originally Posted by 3echo9

Is there a way to visually tell whether it is Dexron VI?

I would go to the shop and ask them what fluid was put in, Dexron/Mercon or the Dex VI.

What fluid does the glovebox manual say to use in your car originally? DexIIIe?

I put Dex VI in my 03 and felt that the shift characteristics changed slowly. I would get longer shifts with a bump at the end after trans was good and warm and at slight throttle just above idling away from a stop sign. Half the fluid was VI from the that drain and change. I did use Walmart's Dex VI for that change instead of a name brand.

I used a suction pump from Harbor Freight on Needmore ($6.99 on sale) and sucked out the 6 quarts into a bucket. It comes out easily and the intake tube fits into the transmission dipstick tube. I replaced that with 6 quarts of Pennzoil or Quaker State Dexron/Mercon from Walmart. Drove about 5,000 miles. Since the shifts seemed to improve at light throttle when warm, I did another 6 quarts. I may have wasted my money with the new fluid, but at 120,000 I don't feel ready for a major trans repair.

Now only 1/8 of the fluid is Dex VI, or about 1.5 quarts out of the 13 quarts.

If I understand your post, you noticed this problem with hard shifts before the CV boot replacement. Did the shifts change if you shut off the car and immediately restarted and continued driving? That resets the electronic controls in the transmission.

Good luck with your trans.

[3echo9]

Originally Posted by imidazol97

I would go to the shop and ask them what fluid was put in, Dexron/Mercon or the Dex VI.

What fluid does the glovebox manual say to use in your car originally? DexIIIe?

I put Dex VI in my 03 and felt that the shift characteristics changed slowly. I would get longer shifts with a bump at the end after trans was good and warm and at slight throttle just above idling away from a stop sign. Half the fluid was VI from the that drain and change. I did use Walmart's Dex VI for that change instead of a name brand.

I used a suction pump from Harbor Freight on Needmore ($6.99 on sale) and sucked out the 6 quarts into a bucket. It comes out easily and the intake tube fits into the transmission dipstick tube. I replaced that with 6 quarts of Pennzoil or Quaker State Dexron/Mercon from Walmart. Drove about 5,000 miles. Since the shifts seemed to improve at light throttle when warm, I did another 6 quarts. I may have wasted my money with the new fluid, but at 120,000 I don't feel ready for a major trans repair.

Now only 1/8 of the fluid is Dex VI, or about 1.5 quarts out of the 13 quarts.

If I understand your post, you noticed this problem with hard shifts before the CV boot replacement. Did the shifts change if you shut off the car and immediately restarted and continued driving? That resets the electronic controls in the transmission.

Good luck with your trans.

I was planning to hit that HF today anyway.

The transmission check calls for the use of Dexron III and Dexron IIII on the Recommended Fluids and Lubricants table. Typo-O?? I think so.

As to when the shifts started..yes they were present before I changed the CV joints. I didn't change them thinking one effected the other. I just had a tear in one of the boots and decided it would be easier to replace the half-shaft rather than just the boot.

I immediately noticed longer shifts and did not feel the bumps into first and second gears. I then had the fluid and filter changed a few days later and a day or two after that the bumps are back but only a little stronger. It's not every time I drive though and not when the car is cold. There may be no link between the two incidents that's just how things have gone down.

I just don't know much about diagnosing t-missions.

Thanks for the response.

[3echo9]

I've noticed the rough shifts are only happening when I drive the car after it has had a chance to warm up. I don't drive more than about 10 miles to and from work each day so I had thought the problem had gone away with the fluid and filter change. It's only on the weekend when I run errands around town does the car start acting up.

I've read some posts regarding a transmission kit for the 4T65E for others who've experience rough 1st and 2nd gear shifts on other GM models.

Has anyone experienced any good/bad results with the mod? Curious to hear from those who've done it.

[ricebike]

(dark brown) I would say this was the first time the T-fluid had been changed. I've only owned the car since June this year.

that color & the prior owner probably never had it changed normally as preventative maintenance are clues as well...