This is slightly off topic, since it applies to a 95 Skylark w/3.1 v6 one of our kids recently got. I've been helping him go through the car. It has < 40k miles on it. While changing air filter, I noticed the old filter was soaked. At first I thought it was oil, but turned out to be trans fluid. I took the short rubber intake hose off as well, and there was some amt of trans fluid in the throttle body entrance. Trans fluid level shows 1 pt low. Any thoughts on what would be causing this. Driveablity is ok, but I think I have noticed a very slight lope.

I've no clue if or how much trans fluid the engine might have already ingested. Any thoughts appreciated.

I've never run into this before.

Thanks in advance.

Is it a stock paper filter or is there a K&N filter?

Sounds like you may have a bad modulator valve on the trans. Here's a pic:

Yeah... I bet it's sucking fluid out of the tranny and into your vacuum lines. Probably has an air line in the intake hose? That would explain the trans fluid in the air filter and tb.

Does that vacuum line connect priot to the throttle body or after?

Now that you mention the modulator didn't Alex have a similar problem with his?

I believe you're right about that, Herc! I once had a modulator valve let go on my '66 Riv, on the way to a cruise night (true dual smoke clouds! ). My buddies asked if I worked for the city's pest control division; I replied that they should thank me for providing them with a mosquito-free cruise night, free of charge...

Thanks for all the replies guys. Stock paper filter in the stock air box. Vac line is just before throttle body, and I haven't had a chance to trace it down as it winds it's way behind the engine. I think you're right about the modulator...been doing some internet research and that seems to be the primary culprit. Seems straightforward enough to replace, but I haven't had the car up in the air yet to take a look.

I don't know how much trans fluid it might have sucked in, but there hasn't been any smoke, so I'm guessing not much.

Any idea on a ballpark cost for the modulator?

Thanks again for the replies.

The vacuum modulator is less than $20 at any autozone.Chico.

Chico didn't you have a tweak for those modulators to firm up the shifts?

I was under the car recently, and it has a 4T60-E transmission (that's what's on the pan anyway). I'm guessing the '-E' transmission code is electronic and not hydraulic?

Is there a vacuum modulator on this trans ? I couldn't find anything on the side of the transmission, but there is something a little higher up that faces upward. The vacuum line from the top of the engine appears to go into it.

This doesn't look like something that would be easy to replace, especially considering the location.

Any thoughts appreciated.

4t60E all have vacuum modulators. They can still be electronic (solenoids and so on) yet require a modulator for function on how hard to shift.

No idea where they're located, but they shouldn't be hard to replace either.

Yes you can buy an adjustable modulator I do'nt have the part # off hand but you can ask for a 95-96 GTP part, the adjustment is not plug and play though start with 2-3 turns on the screw and try ect. Chico.

Sorry for the delay, but yes I had this problem, and yes it was solved by changing the modulator. I change my tranny oil, my engine oil, and change too the vacuum line that goes from the modulator to the throttle.

I finally got around to buying a replacement vac modulator...it looks like the one in the picture posted by blackarrow. However, the existing one on the car looks more like an old valve cover breather. It's much larger, and a light blueish color. It is physically located on the driver's side, front of the transmission, and has one vacuum line coming out of it.

Am I correct in assuming the replacement part I bought is an adjustable modulator and the one on the car is not? If so, am I also correct in assuming it should be pre-set and I shouldn't have to fiddle with it?

..and one final question, is replacement straightforward considering the existing one is slightly different?

Thanks in advance.

The replacement is straightforward and you can use as is or turn the set screw clockwise 2 turns for slightly firmer shifts.Chico.

Thanks for the reply Chico. This task is on my list of exciting car maintenance for this weekend.

I replaced the vac modulator, and it was very straightforward. The trans now shifts more firmly and less mushy and soft as it seemed to before.

I have another question though. Now when shifting the transmission into any gear, the engine really moves a lot in the engine bay. Perhaps as much as 3-6 inches based on just watching it while someone else shifts the car. This seems excessive to me, but I'm not familiar with the setup on these 3.1 liter engines in the N-bodies. Because of the age of the car, I'm concerned about this engine travel causing premature engine or trans mount failures...or something else for that matter.

I'm wondering if I should get a non-adjustable modulator from a parts store and put that in instead of this adjustable one.

Thanks again for all the input on my original question, and thanks for any thoughts on my additional question.

sounds like it would be a motor mount

I concur. The mounts are probably already toast (I wouldn't be surprised if mine were). Also, look over your torque struts (dogbones). I assume it has at least one since GM used the design pretty frequently. It could be worn as well and exists to help prevent the engine from moving.

Thanks for the replies. I don't have a shop manual for this car, so I have to go looking for everything on the car itself until I find it. This engine doesn't have dogbones like on the GP. It does have one mount on the passenger side that has to be dealt with in order to replace fan belts by the looks of it (bummer). This mount is attached to the frame near the passenger side fenderwell.

I'm assuming it also has a trans mount somewhere underneath near the driver's side, but haven't looked for that yet.

As a side note, this car has a strange setup for steering, since it appears part of the steering setup is actually above the wheels and attaches to the firewall. It also looks like CV boots in the same general area. I'll bet it's a real joy to work on that stuff. Hope I don't have to tackle any of it.

Yep the excessive rocking sure sounds like bad motor mounts. When you buy new mounts get the tranny mount as well.

yeah, you dont want to put more pressure on any of them. Just get all new