Transmission Slip, Dipstick Overfull

snaphappy · June 27, 2013

230,000 miles on 2002 Suburban Z71 4x4 5.3. Runs great. AC is great.

From a deadstop the tranny does not like to engage, it slips a bit, hesitates, then battles its way into second gear. California stops, on the other hand, are smooth. All other shifting is fine. Sometimes there's a bit of surging out on the highway.

The quick answer is - rebuild the transmission. But I wanted to share my experience, or in-experience ;)

Drained the fluid, removed the pan, cleaned the magnet, put in a filter. Yup that's when the slip started. Lots of folks say not to put in clean fluid for this very reason. New fluid comes in and breaks up gunk and next thing you know the transmission is slipping.

So that seems to be what happened to me.

Once the slipping started I checked the fluid. It has bubbles and it's overfull, in fact, 1/4" above the hot zone. Wow. Ok. My brother wants me to put in sea foam. I say not until we get the fluid at the right level. (To check the fluid, I followed the procedure in the manual, so no worries there.)

Today I drained some fluid. Put the drainplug back in. Started the truck, checked the fluid in park, still overfull. Well dang. Let's drain some more. Ok done. Check the fluid again. Still overfull. Getting weird now. Finally get the fluid down to the correct level, according to the dipstick. Yay! Put in the sea foam. Done. Time for a test drive right? Nope! It won't go into gear. At all.

So I check the dipstick. Yup, fluid is just right. Before I start crying I add some fluid. Still won't go into gear. I add some more, boom! Goes into gear. But only for a second. Then I add a bunch of fluid. Everything seems fine so I take it for a test drive. Still slipping at takeoff, just like it was before.

But here's the weirdest thing. The fluid is about half an inch above the hot marker. But before I over filled it, the transmission wouldn't even go into gear! Maybe I don't have a factory dipstick, but it looks exactly like the one in the owners manual and my Haynes book. So I'm pretty sure it's the right dipstick.

Anyway, it's drivable. Will die soon I'm sure. Need to save a bit of money before I can have it rebuilt. But comments, criticisms, all very welcome!

aflesch · June 27, 2013

It sounds like the new filter isn't sealing correctly (or is cracked). It reads overfull because the pump is sucking air and creating a lot of bubbles. When you have the oil level correct the leak is exposed and it can't build enough pressure to go in gear. When you over fill it it covers the leak and it's not sucking air anymore.

This is just a theory and I have never seen that happen before but from what you are describing it sounds plausible.

snaphappy · June 27, 2013

I put the filter in. So there's a possibility it's not in right. Interesting! Too bad it's such a mess to get in there and check, but don't have a choice.

gmtech4 · June 27, 2013

engine off ,check the level,

start engine ,check level,...

if its the same ,you messed up the filter install,drop pan and put it in properly

snaphappy · June 27, 2013

Brilliant! I need to take you guys out for beers!!!

Carder09 · June 27, 2013

I meant to add my 2 cents before your last post, so I'll take that beer.

CapitalTruck · June 27, 2013

Be sure to tell us how this turned out!

snaphappy · June 27, 2013

Just checked with engine on and off. With engine off fluid was significantly higher. If you can visualize the dipstick in your head, there's a big gap between the hot/full mark and where the engraving "Check with engine on" appears. With the engine off, the fluid is just a couple centimeters beneath the C on Check. Wow. With the engine running it drops about an inch maybe.

But look, I still think it very well could be the filter. I got the filter from autozone. You know the round metal seal that comes with it? I had the hardest time getting that up in there. If I drop the pan and start over, I'm getting the filter from Chevy this time. The Chevy filter broke off when I took it out. Had to chisel the seal out of there. i'm sure that happens all the time on older trucks.

aflesch · June 27, 2013

It could still be sucking air even though the level drops. If it is sucking any oil at all the level will drop but if there is air in the oil it won't build pressure.

snaphappy · June 27, 2013

It could still be sucking air even though the level drops. If it is sucking any oil at all the level will drop but if there is air in the oil it won't build pressure.

Yeah I'm going to get the filter from Chevy, go through it all again. It's really my only option. If that doesn't help it, what else can I do? If I can get 3-6 months more out of this thing before the rebuild I'd be happy. Just bought the wife a darn trip to Mexico. Cash is not as plentiful!

Should I put sea foam right off the bat this time? Or just skip it?

aflesch · June 27, 2013

I wouldn't put Seafoam in it at all. If redoing the filter job doesn't fix it, it needs a rebuild. Just drive it till it quits. I can't come up with anything else that would cause that, that can be fixed with the tranny in the truck.

snaphappy · June 29, 2013

Dropped the pan tonight. Transmission filter was laying in the pan. I drove this thing for about 600-700 miles with no filter I guess. Wow. I feel like a complete moron. I wish I didn't have to learn everything the hard way, oh well.

So I'm holding the new filter seal, it's O shaped, trying to jam it in there. Just like last time I can't really get it in. When I get one side of the filter seal in the other side pops out. So finally I did some searching online. I used a deepwell socket and got the filter seal about 75% in, far enough that I couldn't get it back out. I just pushed on the deepwell socket with all my might and it went in part of the way. But according to what I read online, the transmission filter seal needs to be flush - it can't be sticking out at all. So at the point I used a hammer and a punch. I beat on it gently until it was flush. I was shocked when it was all in. I went over with my finger again and again in disbelief. Ha! Then I put the transmission filter in, but you can't just slide it in. You really have to push the transmission filter up in there with a lot of force to get it secure. Needless to say it won't fall out again.

Took it for a test drive and it's like new. Seriously. There's so much torque the truck pulls me up the driveway without pressing the accelerator. Not bad for 230,000 miles.

Here are some keywords for anybody with the same problem doing a Google search looking for help: Replace transmission filter, seal, fluid, gasket, 4L60E, Chevy Suburban 5.3, trick to put in transmission filter seal.