First time changing fluid in A/T

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Bulli

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96 cavalier, 76k miles on original ATF.

I got the procedure down already,

Warm up vehicle
unbolt pan
clean pan
replace filter
clean magnet
replace seal
bolt it back together
add new fluid


the car calls for Dex III and at Wallmart i saw Pennzoil ATF tat was DEX II,III,ect ect. compatible.

Will it work on my car without problems?

I understand DEX III is not being sold anymore

i believe i will be able to remove 2 quarts so i probably have to repeat all this about 3 times to completely drain and refill the transmission?

Should i use regular, dino ATF, or go with some better stuff like Amsoil ATF, or M1?
 
Warming the ATF will put more back in the trans. I'd let it sit over night so you get as much of the factory ATF into the pan.

I made the mistake of warming the ATF in my Corolla before draining and dropping the pan. The transmission was still dripping 2 hours after the pan was removed.

I'd go with Valvoline since they are the only one that makes GM approved synthetic Dexron VI and available at local auto stores. This thread has some more info:

https://bobistheoilguy.com/forums/threads/dexron-iii-made-anymore.91927/
 
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I think that for the additional drain/refills after the pan removal drain that you can suck & refill to get your 90% + new fluid. Another thought is, you may want to put a drain plug in the pan for future use.
 
I'm sure the Pennzoil Dex ATF is fine but I prefer to use Dex VI since it is the current spec. for GM transmissions that spec.'d Dex III.

What trans do you have? I had a Corsica once that had the 3-speed (3T40) and it took about 4 qts to refill. I think that the 4T40E 4-speed will take even more fluid, perhaps 7 qts. Which one do you have?
 
i dotn know waht i have its a 4 speed i believe, where do i look to chek which one i have?
 
Hi Bulli,

I don't want to put the scare into your project, but would rather prepare you for the unexpected.

On a car this old,it's not uncommon for one or more of the transmission pan bolt holes to be seized (steel bolt in aluminum threads). When you try to take the bolt out, the aluminum threads might strip out with it. Or, the bolt might break off.

If your bolts have exposed holes on top, spray some penetrating oil into them a few days before your project.

With stripped female threads, sometimes you can run a longer bolt in to catch good threads higher up. Sometimes you can tap the hole one size bigger. A helicoil is another option, but they are expensive ($20-$30). I know some who just run a self tapping bolt into the hole and call it good.

A broken bolt is tougher. Drill it out and use an easy-out, but this is tricky.

Others I know leave a bolt out if all the others are good. Sometimes it works.

Don't over torque the new installation and crush the gasket or strip new threads.

Good luck. I relay this info because my siblings Sebring had one bolt hole strip out recently. I was lucky and got by with a longer bolt.
 
I switched to Dex VI in my 93 jeep (called for Dex II) and I really liked the fluid. Transmission always shifted like it used to only do once warmed. No sluggish cold shifts anymore. Good fluid!

M
 
Originally Posted By: Bulli
i dotn know waht i have its a 4 speed i believe, where do i look to chek which one i have?


The only thing that matters is that you have enough fluid on hand to get the job done. I'd buy 8 qts which will be enough for any GM FWD trans and keep the extras till next time if there is any left over or return them.

The only stripped bolt I've every had on a trans. pan was my '01 Grand Prix and GM provided that to me right from the factory. I've never fixed it and never had a leak either and I'm about to take the pan off again at 90k miles.

Be sure you hand start each bolt, don't try starting them with a air or elec. driver. You don't want to cross thread them. They should spin in easily. I usually just use a small 1/4" socket to drive them in the rest of the way so I can't over torque them. Then I use a torque wrench to tighten them down to the final torque. I don't recall what the final torque should be but it is pretty low.

Most likely you won't have any bolt issues but it was good of doitmyself to prepare you for what might happen. Good luck.
 
alot of people are telling me new fluid will wear out the tranny more.. is this true? should i just keep this fluid in for life?
 
Don't listen to them. Keeping the old fluid in there will fail the transmission sooner rather than later... even if the fluid has been in there for too long.

After the fluid change, and if your transmission has any electronics, you'll probably want to disconnect the battery for a bit. This will force the transmission to relearn the shifting parameters with the new fluid.
 
I would do as you are planning to for the first drain, then do the rest via the cooling hose. You will have the least mixing of old and new fluid this way.

One you have the pan off you will have an idea of how bad things are in your tranny.

Consider a Magnefine filter, less than $20, good investment.
 
I've never heard that about disconnecting the battery, is that true?

Definitely don't believe what people tell you about new fluid hurting the tranny, it can only help it. I've seen tranny's with black fluid that don't even shift work good as new as soon as you change the fluid.
 
Originally Posted By: Chero87
I've never heard that about disconnecting the battery, is that true?


Yes, this is how the ECU is reset. Force the computer to relearn and optimize car's performance.
 
Is disconnecting the battery to force the ECU to re-learn for GM only or should this be done on any make tranny?

I have a '91 4Runner, with this work for Toyota also? Just changed the fluid 2 days ago, have put maybe 50 miles on it since.
 
[censored] on the Dex-III not needing to be changed.

Listen for the number of shifts you hear as you accelerate onto the highway. If it's 2, you have the 3-speed. 3 shifts, then the 4-speed.

Also check the gear selector. If it's a D, 2, 1, then it may be a 3-speed. If you have the D with a circle around it, then D, 2, 1 you have a 4 speed.
 
in the owners manual it said
its a 3 speed if it has

1 2 D

and a 4 speed if it is

1 2 3 D

So i have a 3 speed. Thats odd i always thought it was a 4.
 
Originally Posted By: Chero87
Is disconnecting the battery to force the ECU to re-learn for GM only or should this be done on any make tranny?

I have a '91 4Runner, with this work for Toyota also? Just changed the fluid 2 days ago, have put maybe 50 miles on it since.


Resetting the ECU is something I learned from 9thgen and toyota nation. Its best practice, not mandatory.

Disconnect the negative battery terminal. Turn on the headlights for 3 seconds. Step on the brake for 3 seconds. Reconnect the negative terminal. This is to drain the power out of the computer faster instead of having to wait 2-3 hours.

The clock will have to be set again. Thats how I know the ECU has been successfully reset.
 
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Well tried the disconnect the battery and reset the ECM trick, and now I have a pretty substantial miss in the engine...did I do something wrong?

I disconnected the Neg cable, turned the lights on for a few seconds and shut them off, nothing happened, no lights came on obviously.

Hooked the Neg cable back up about 2 hours later, all the lights blinked for about a minute like the Hazards were on, no headlights, just parking and dash lights, then shut off. Then opened the door to get in and they all started blinking again, this may be due to the old alarm that is still in there, doesn't work, just in there still.

Started it up and it started fine, ran fine for a minute then started to idle real low and miss, backed out and started to go and now have a definite miss/stumble when starting from a stop.

Could this be because the engine ECM was reset also? I don't see why it would miss because of that though, it should have been fine as soon as I started it up and the ECM was powered up.

Only other thing I can think, is that I had to roll it back a bit while the battery was disconnected, so I turned the ignition on and put it in Neutral so I could push it back, but it was for like 15 seconds, could that have hurt the ECM?

Pretty frustrated.

Thanks.
 
If you have a dipstick, then you have a 3-speed, and a much easier job on your hands. With the 4-speed, you have to a pull a little plug that's in a hard-to-reach place and fill the transmission until fluid starts dripping out the hole, then put the plug back in the dripping hole. All while somehow trying to keep a drain pan under the plug properly, even though that's the same exact area you need to be working in.

I don't think a 4-speed was even an option on these cars until 1998 or so.
 
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