Tahoe tramission, unlocked and rpm's flew up... ideas?

GlockLT4 · 09-29-2009, 02:07 PM

2004 5.3L 2x4 Tahoe, 4speed, 60k miles

While in 2nd gear and accelerating nicely my Tahoe stopped going forward and rpm's flew up to 3-4k. Let off the gas and then tried again and it caught. Happened to me 2-3 times this morning on my way to pick up a friend to carpool to work. First time I thought something really weird with transmission was going on and it was just acting up due to cold. 2nd time i knew it wasn't just a coincidence. Got to buddies house and checked tranny fluid to find it was about half a cm below the hot marks on the dip stick. Took it to O'Reilly's and added just over a half quart. Haven't had the problem since.

When on the way to my friends house I called a transmission shop and mentioned the symptoms. He said that the 4L60E has a piston that holds the lock in the TC and it was releasing. No codes thrown, but he said he'd scan it and a rebuild is $1350 (how nice of him to mention that right away, ha).

When i got the quart of ATF at O'Reilly's, the guy there mentioned the same issue with a piston problem of 4L60E's and that it's about a $300 replacement. I told him of the low ATF level and he said that could cause it too, which makes sense to me.

Haven't noticed the problem since adding the half quart. You guys think that's all it was or does it really sound like the elec piston holding the lock on the TC needs to be replaced?

I believe the reason I noticed it this morning for the first time is because it was about 56 degrees out (coldest for Dallas in a while), and with cold ATF the low oil level showed up as a problem more easily.

rgregory · 09-29-2009, 02:49 PM

On my Tahoe (01) I never had that exact problem but it would sometimes slip in first gear when I first pushed the gas a simple fluild and filter change and it has been fine for 40k miles. Even if the TC is unlocked your RPM shouldn't fly up. It will go a little like 1000 rpm similar to when you leave from a stand still the TC is not locked and the rpms will only go up a little. It sounds more like a clutch slipping. If you haven't already I would try a filter and flush first.

I would be surprised if the TC locks up in second gear under any situation.

GlockLT4 · 09-29-2009, 02:56 PM

Quote:

Originally Posted by rgregory

On my Tahoe (01) I never had that exact problem but it would sometimes slip in first gear when I first pushed the gas a simple fluild and filter change and it has been fine for 40k miles. Even if the TC is unlocked your RPM shouldn't fly up. It will go a little like 1000 rpm similar to when you leave from a stand still the TC is not locked and the rpms will only go up a little. It sounds more like a clutch slipping. If you haven't already I would try a filter and flush first.

I would be surprised if the TC locks up in second gear under any situation.

Ah true about 2nd gear. Been a while since I've worked on an auto tranny. Agree that it may not be the TC locking up but the clutches slipping off completely. It's like pushing in the clutch on the vette, so that makes more sense. I guess that's possible with low fluid.

Good advice on the fluid/filter change. It is time for that anyway.

rgregory · 09-29-2009, 02:58 PM

Quote:

Originally Posted by GlockLT4

Ah true, it may not be the TC locking up but the clutches slipping off completely. I guess that's possible with low fluid.

Automatics are all about pressure. So yes low fluid also old fluid or a partially plugged filter doesn't help.

GlockLT4 · 09-29-2009, 06:05 PM

Quote:

Originally Posted by rgregory

Automatics are all about pressure. So yes low fluid also old fluid or a partially plugged filter doesn't help.

Yep!

juiceman03070 · 09-30-2009, 08:47 AM

As stated ..I would have the entire tranny flushed and filter and fluid changed ...

GlockLT4 · 09-30-2009, 11:56 AM

Quote:

Originally Posted by juiceman03070

As stated ..I would have the entire tranny flushed and filter and fluid changed ...

Cool, thanks. Having it done today.

GlockLT4 · 10-01-2009, 04:59 PM

Got the truck back last night and it's fixed. They ended up replacing all 4 of the solenoids after reproducing the problem still even after I added a half quart of tranny fluid. Drove it home and it felt much better. Not sure that all 4 of them needed to be done, but "while in there" they are only $20 parts, so whatever. Had it done at AAmco with 10% off coupon for $275 after tax. Not too bad considering that a fluid/filter change alone normally runs $110.