Transmission Modulator

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Molly1998

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I have a 1998 Pontiac Montana (yep, it's my mommy van :) ) that will shift hard quite often. I was wondering if anyone knew how much/little the modulator has to do with this? Would replacing it fix the problem possibly?
 
Honestly when was the last time it was serviced?? trans flush and filter changed
 
that is a possibility along with the shift solenoids
 
I changed the trans fluid 3 years ago...it started shifting rough not so long after that.
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How many miles? It only shifts hard and nothing else? No stutter? 'Bang into gear' when taking off ie at a light.
 
the van has 154,xxx miles on it. It does not stutter or makes any strange noises really...well, it kinda whines sometimes...but yeah, shifts hard.
 
Is there a check engine light lit up?

Have you looked at the fluid does it smell or look burnt?

What type of fluid was used with the last service?
 
The check engine light is not coming on and the fluid does not appear to be burnt or have a smell to it. I really don't know what fluid was used last, but I did have to add some (due to a leak) and I purchased some at Autozone - I can't remember the brand, but it was in a white bottle and said it was good for hard shifting. I added nearly 2 bottles a few months ago.
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Sounds like you added Lucas. http://www.autozone.com/motor-oil-a.../lucas-oil-transmission-fluid-fix/202087_0_0/

Where is it leaking from? If it's the pan gasket, I'd just go ahead and drop the pan, replace the filter, and fill with (guessing till I look it up) Dextron III. Also note that transmission problems can be caused by bad engine readings. This is such that the transmission 'acts-up' because of a bad reading from say a dirty MAF, bad spark plugs, engine temp sensor, ect. Also one of your trans solenoids could be clogged/dirty as Mel suggested.

When it hard shifts is it only 1-2 2-3 from take off?

Will you be looking at this yourself/with help ie in person or bringing it to a shop?
 
Yep, that's it - Lucas.

It leaks from a line that connects to the radiator. It's not a big leak...about quarter-sized after driving it. When it does decide to shift hard, it does it through all the gears, actually.

I am not mechanically-inclined at all...any work done will have to be at the shop...although, I did watch a video on replacing the modulator...it looks too simple...but I guess that depends on where it is located.
 
Yeah, location is the nature of the beast on modern cars. I'm surprised - have you tried tightening the connection at the radiator? I know it sounds dumb but why not - I don't know the size but probably 13mm or 15mm wrench is all you'd need - If it works it would save you that money on the leak.

Take a pic if you can of the fluid. Also if you have any tools start checking those spark plugs. Transmissions on controlled by a computer and the computer makes it act up based on all sorts of readings. In other words, everything needs to be working properly. You'd need a 16mm or 5/8 socket to get those spark plugs out. Pull them check the brand - these engines are temperamental about their brand and check the condition of the sprak plug. Check around with people you know and see if you can get your hands on a live data OBD-II scan tool. It doesn't have to be super high end, just something with live data.

IDK someone else can chime in on the lucas - I personally don't put other chemicals - ie only trans fluid for my trans, oil for the oil, ect. I know that lucas stuff is pretty thick. I am unsure how that effects the system if the ratio is high or whether or not it will at all.
 
I will definitely try tightening that...it would be very good on the checkbook to have it be that easy of a fix.

I don't know about the spark plugs and all that....I don't have confidence in changing them out myself.:confused: That is a good idea to probably change the spark plugs. Is there a specific brand to use for those?

I hope we hear about the Lucas oil...hopefully it hasn't messed with anything.
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AC Delco is what I always use for my GM engines. NGK is also a great brand but I have not put them into my engines - So my verdict is stick with AC Delco. I have confidence you can do this as it is just a matter of pulling the spark plug wire off and putting a socket down the tube to get them. However many people break the spark plug wire when pulling them off so it would be advisable to get a spark plug wire set while you're there. They are relatively inexpensive. Just put di electric grease on them and anti seize grease. Your auto parts store will know what you mean.

Or again, you could have some one do it. Also clean the MAF and throttle body. Your local auto parts store will have a cleaner for that specially and usually you can buy a small MAF cleaner in combination (same package) with a throttle body cleaner. After that, I'd say do try to get your hands on that live scanner to see what's going on and what the sensors are reading.

The above suggestions can be done relatively* easy by yourself. Because of the orientation of the engine, it may be better to have some one do it for you because those "back" or firewall side spark plugs can be buggers for a first timer (no offense). If you take it in, these can be pricey - I heard a friend of my replaced her cabin filter, fuel filter, and oil and it came to around $160 at a Kwik Kar. (BTW you might as well change the fuel filter if you have not in a long time)

You should always do the maintenence first to see if that routine maintence solves your issues. Then just keep up with it. IDK the life of that transmission fluid - guessing 50k miles so it might be time to do that again anyway too. Just pull the pan, replace the filter, check the gasket is in good shape, then torque the pan back on, and fill with (guessing 7 Quarts) Just some food for thought.
 
No offense taken...I am a newb...beginner...lol...anything else that applies too. No shame in the truth.

I appreciate the help with this!
 
Molly1998 said:
I will definitely try tightening that...it would be very good on the checkbook to have it be that easy of a fix.

I don't know about the spark plugs and all that....I don't have confidence in changing them out myself.:confused: That is a good idea to probably change the spark plugs. Is there a specific brand to use for those?

I hope we hear about the Lucas oil...hopefully it hasn't messed with anything.
Click to expand...

Replacing spark plugs on your vehicle is quite tricky. Front row of cylinders is very easy to access, but rear one is a pain in the ass. Garage would charge you 2 hours of labor for spark plugs
 
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