Lanos Automatic Transmission Problems!

[BosnianLanos]

Long post cometh but please bear with me, I need some help.

For a long time now, maybe 1-1.5 yrs, my Lanos's AT pan gasket was leaking. Not a drip leak, but it was moist all the way around, basically the rubber gasket turned hard and lost all of its sealing properties. So, I bought a gasket and filter kit at Autozone and went to the junkyard to get the pan as mine was fairly dented from being attacked by various urban obstacles. I found a pan on a Nubira, but it had some sort of rubber plug pierced through the metal that we though would hold, so for $5 we got it.

Well, the first change went without a hitch. The new pan fit perfectly as did the gasket and filter. Test run went smoothly and we were all happy, but owning a Daewoo, I quickly learned all is not as it seems.

Well, we wanted to give it a good test run so I let my dad drive it as I wasn't planning on driving it that night. Two hours later, I get a call from my Dad saying that all of the fluid leaked out, he said through a missing screw hole. Terrified, I hopped in the Honda and "sped" ('cause we all know a Honda can't speed ) over to where he was. I look under the car... the rubber plug popped out and it was over; all fluid gone, however, it had not gone dry when the car was running, but parked and off. Well, I get a tow home and the very next day I reinstalled everything including my old pan which I luckily saved. I refilled with Valvoline ATF and all is well and smooth again. Happy, happy.

Well, problems arose again because we didn't know exactly how much ATF to put in so we put in 7 quarts like the manual said. Every once in a while, in the low RPM the car would jerk moderately but when turned OFF and back to ON it went away. So, with every jerk I added a bit of fluid, thinking it was underfilled but it didn't stop jerking. So, thinking that we were seriously low on fluid, I looked in the manual for a check plug and found it. So, today, I parked on level ground and after some serious trouble, managed to get it out. A tsunami of ATF came out through the "Level" hole which was supposed to mark the level at which the ATF should be.

I was totally stumped. Instead of underfilling, it looked as though we overfilled by at least 1.75 Quarts. So, we put the plug back in and went on a test drive expecting the worst, but the car drove smoothly and calmly with no jerking.

Basically my question: Is it possible to get jerking and occasional hesitations to go into gear by overfilling the transmission? Is there any way to be sure that I have enough fluid in the car as I don't really trust the plug. OR worst case scenario, is my car permanently damaged from all the ATF leaking out with the car off?

Please help as I have come to far with this car to see it die due to an American transmission and Bosnian stupidity.

Thanks, Damir.

[scarr]

Well, it is possible to experience jerking if you overfill the Transmission fluid because you are over-lubricating the gears causing them to slip just like they would if they were under-lubricated.

However, I've changed my AT pan gasket 3 times (hope you used some gasket sealer on it or in 6 mo. you will be changing it again) and each time, I've put 12 qts of fluid in. My mechanic, who specializes in nothing but Daewoos, told me it requires the whole 12 qts of fluid after a gasket replacement.

[MMamdouh]

arent auto tranny woos got a dipstick for tranny fluid?? i know manual tranny got level plug but whats the deal with the auto??

anyways the level plug is what every one adjusts his tranny fluid against.

MMamdouh

[BosnianLanos]

No, the Automatic 4T40E Transmission doesn't have a dipstick. Some crackhead in GM thought it would be a good idea to leave it out of the design to leave us all guessing. I guess they thought that since you never "have" to change the fluid there is no sense in putting in a dipstick. But they never planned on a 190,000 mile Daewoo.

Well, after more testing last night, it seems that the plug thing worked because the car is smooth, responsive, and doesn't jerk or hesitate to go into gear. But I'll keep you guys posted.

[tango]

Hey Bosnian. Don't worry. That tranny is descended from the best tranny ever built, the TH-125C. It's tough as nails and goes forever! I was TOTALLY shocked when I saw the name of your thread! I was like: "Daewoo with tranny problems?!? IMPOSSIBLE!" As I thought...it was an isolated incident. But to back up what Scarr was saying, anything can happen if you alter the pressure of the internal hydraulic system of the tranny. I had an ATF cooler on my Cielo and I actually experienced gear HUNTING when going downhill! My car normaly holds the gear for a few seconds...if the brake isn't depressed it upshifts to the next gear. With the tranny cooler it would hunt up and down! I promptly removed the cooler and all was right in the world after that. Do you guys now see why I don't recommend modifications?!? SHEESH!

[BosnianLanos]

LoL.

After even further testing today, still no problems, and careful not to count my chickens early, I believe that the issue is resolved. I tried some WOT passes and the tranny was strong, quiet, and smooth.

I am also quite surprised with how well this tranny is holding up. Initially I was like "Crap...GM American POS transmission is gonna die on me", but this tranny and motor have proven their worth time and time again, and anyone who disses Daewoo drivetrain quality in front of me gets slapped in the mouth. :twisted:

Which isn't to say that I ain't ridin' around with 3 bottles of ATF fluid in my trunk...Just to be safe... .

[woo]

i just had a new transmission put in my leganza, as i more or less shattered all the internals into a fine paste due to a rather large bearing failure. Thats one experience i dont recomend

[MMamdouh]

if the lanos auto tranny so good, what about the manual ones?? are they as reliable as the autos??

MMamdouh

[tango]

I've never heard about a manual trany failure in a 'Woo either. But don't be fooled by what you hear. GM trannies are the best on the planet. That's why BMW, Jaguar, Rolls Royce and a few other manufacturers relied on them when they needed cost-effective auto trannies when Europe didn't make any. The partial reason for many American tranny failures is how the hydraulics are set up. When an auto is made to slip to the next gear seamlesly there is actually more harm being done than if it is allowed to simply slam in. The crisp changes I have experienced in my Cielo (crisp, yet not uncomfortable, as in my brother's old 1989 Toyota Corolla wagon) are a dead giveaway to intelligent programming. When I looked under the bonnet of the Optra and didn't see that familiar P shape I was a bit concerned. Only time will tell if those are as good. I don't even know the name of it...anybody figure it out yet?

[BosnianLanos]

Yeah, I've noticed the "crisp" shifts too, especially from First gear into Second gear, and then less and less. I feel it is a lot better than, for example, my Honda tranny where the only way you know it shifts is by looking at the tach and just seeing the needle drop to a higher gear.

Woos are Frankenautos Italian design, German engine/suspension, American transmission, all wrapped up into a curious little Korean car.

[DomWoo]

after i took my car in to the shop to have the fluid changed i noticed that once in a blue moon it would jerk really hard and i would ahve to shut down and start up again to get it to stop.. now i know why.. thanks

[Mario]

When I looked under the bonnet of the Optra and didn't see that familiar P shape I was a bit concerned. Only time will tell if those are as good. I don't even know the name of it...anybody figure it out yet?

As said in the service manual, the trans we get depends on the engine.
1.6L gets an Aisin trans.
1.8L and 2.0L have the ZF 4HP16

[tango]

When I looked under the bonnet of the Optra and didn't see that familiar P shape I was a bit concerned. Only time will tell if those are as good. I don't even know the name of it...anybody figure it out yet?

As said in the service manual, the trans we get depends on the engine.
1.6L gets an Aisin trans.
1.8L and 2.0L have the ZF 4HP16

HOLD ON!! Hang on a sec! Are yout rying to tell me that in the 1.6L that I am trying to get there will be a JAPANESE transmission?!? Oh hell no! Somebody tell me it ain't so!

[tango]

<sigh> I did a quick search and came up with these links:

GMDAT Transmission Final Drive Ratios

GMDAT Transmission Gear Ratios

Seems also that GM and Aisin have some agreement to replace the trannies in some of their Allison applications. Closer look at the gear-ratios of the 4T-40 and the 81-40LE and we see that 2nd and 3rd are identical. Final drive, 1st and 4th differ, however with a slightly taller gearing in the Jap on all figures. So it seems fuel efficiency is the personality of this unit. We'll see.

[restino]

my tranny fluid is leaking out from that block area or at the hose connections where they go into the tranny side by side. not sure yet.

A - if you have time i would like to ask you how this cooler can be cleaned? or do i need to buy another one? how does it fit on the radiator. is it screwed on? any ideas?

B - how can i see if the tranny has enough fluid? there is no dipstick. when i use a flashlight to look inside its empty all the way down to the metal as far as i can tell. do i fill it all the way up until the threads are gone?

C - what type of fluid can i use?

D - also, is there anyplace good on the internet that has documents on how to fix daewoo lanaos 2000 problems?

E - my check engine light is one, do you think it could be becuase of the low or missing tranny fluid?

thanks for any information you can give,

restino