Topic: The Problems Continue...My new 1971 Trans Am

[b_hill_86]

Sorry to hear man. Wish i had a solution for you. Hang in there, you'll get it figured out.

[Justin]

Wow man. That really sucks. Stick with it. You'll figure it out. Don't let this bring you down.

[Tin Indians Rule]

Where is the vacuum to the modulator coming from. Could high RPM's increase vacuum in such a manner that it pops the modulator. Try changing the source of the vacuum if there is a port that doesnt produce as much vacuum.

Im not sure if thats an option. But was a thought I wanted to share.

[oldskoolubr]

Don't give up, I did that with one of my cars I thought I had tried everything and it was a pushrod tip.  It was broken but still sitting on the pushrod so I couldnt get an accurate adjustment.  Talk about kicking myself in the A$$!

[Striker]

Are you sure it is trans fluid and not antifreeze/water? Does the engine oil look ok, is there any traces of milkiness? If the modulator was leaking badly there could still be traces in the muffler that are burning off especially during higher rpm and forced out heavier with increased exhaust pressure.I would think the trans fluid would be more blue though.

Yeah, It is def Trans Fluid. After the modulator was replaced, I drove it locally for about 50 miles, then jumped on expressway, and Bam Same result. I wold assume it would have all burned off long before I took it back on the expressway?

Engine Oil is VEry Clean, and full. Coolant is Full as well. Trans was a 1/2 qt low. This happened after 6pm, so I will be calling the shop again this morning. I am getting sick of every time I take it out, something else breaks.

[mr71transam]

After you get the car home and let it sit a few days. Do you have any fluid pooling under the car. If so what is it transmission or coolant?

I’ve had both types with my 71 Trans Am. The transmission leak looked like it was leaking around the Modulator, but in fact it turned out to be the transmission cooling lines. They were actually leaking where the lines connected to the transmission. Over time they had gotten a little lose. Are you losing transmission fluid?

The coolant leak was where the heater hose connects to the passenger side head. it would only start to leak after the car warmed up and the pressure built-up. Is your radiator level dropping? Are you losing coolant?

[Striker]

After you get the car home and let it sit a few days. Do you have any fluid pooling under the car. If so what is it transmission or coolant?

I’ve had both types with my 71 Trans Am. The transmission leak looked like it was leaking around the Modulator, but in fact it turned out to be the transmission cooling lines. They were actually leaking where the lines connected to the transmission. Over time they had gotten a little lose. Are you losing transmission fluid?

The coolant leak was where the heater hose connects to the passenger side head. it would only start to leak after the car warmed up and the pressure built-up. Is your radiator level dropping? Are you losing coolant?

When the car Sits, it does not leak any fluid at all. The Radiator is full, but the trans fluid was a little low only after it smoked. After the car smoked out, it drove home fine with no smoke, but I kept it under 2500 RPM. Is there another part the would be pulling the trans fluid through the exhaust manifold? Its def coming from the tailpipes. Thanks for the response, and help! I really want to get this car running.

[Tin Indians Rule]

The vacuum line is pulling the fluid from the modulator through the vacuum line and into the intake. Depending on where your port is on the intake its probably sucking it into cylinder #8 and burning the fluid. Making it smoke like a "Texas Skeeter Killer"

It happens. Theres only a few reasons it can happen

[ShakerBreaker]

Where is the vacuum to the modulator coming from. Could high RPM's increase vacuum in such a manner that it pops the modulator. Try changing the source of the vacuum if there is a port that doesnt produce as much vacuum.

Im not sure if thats an option. But was a thought I wanted to share.

I was wondering something along these lines, too.
Like too much vacuum collapse a diaphragm?

[bobg]

If original fluid burnt off and it is indeed trans fluid going in the exhaust still, then yes it has to be pulling fluid past the modulator.

[pancho400cid]

If the problem is the modulator, then there will be red transmission fluid in the line from the modulator to the manifold.  Pull the line.  Based on the volume of smoke you describe, if it isn't dripping trans fluid,  the modulator is probably not the problem.  Also, if the diaphram is ruptured, the transmission would not shift.

If the test above points away from the modulator, I would do a compression test on all 8 cylinders.  As mentioned, keep checking the oil looking fro milkiness, choclate milky looking stuff, etc...


Great car.... it's just testing you.  Show it who wears the britches!

[Tin Indians Rule]

Fluid doesnt run uphill from the modulator to the intake on its own. needs vacuum to get it there. Dont believe for a second that lack of visible evidence (fluid dripping from line) will eliminate the modulator.

[pancho400cid]

Agree fluid won't run up hill... without vacuum... But there would be vacuum if the diaphram is ruptured and fluid can most certainly be "sucked uphill" (see also "drinking straw")....

It would take a lot of oil to make as much smoke as he's talking about, and the possibility of rupturing two modulator diaphrams in a row without seeing any shifting problem seems like a very low probability to me.

[Tin Indians Rule]

If the engine isnt running there will be no vacuum is what I was saying. So as soon as you shut off the engine any fluid in the line will run back down and into the modulator leaving only residue on the inside of the vacuum line. NOT PINTS!

How about take two seconds and explain what you are really trying to say with the see drinking straw comment!

You are sadly mistaken if you think it takes a lot of transmission fluid to make smoke. Try it. We used to start fires with it before EPA regs were invented. Signs of a mispent youth. 

[Striker]

If the problem is the modulator, then there will be red transmission fluid in the line from the modulator to the manifold.  Pull the line.  Based on the volume of smoke you describe, if it isn't dripping trans fluid,  the modulator is probably not the problem.  Also, if the diaphram is ruptured, the transmission would not shift.

If the test above points away from the modulator, I would do a compression test on all 8 cylinders.  As mentioned, keep checking the oil looking fro milkiness, choclate milky looking stuff, etc...


Great car.... it's just testing you.  Show it who wears the britches!

Thanks for the input! I know I am being tested, but I will Eventually win. This is the car I had my heart set on for a long time. The oil looks great as of right now. Not low, and very clean.

If the engine isnt running there will be no vacuum is what I was saying. So as soon as you shut off the engine any fluid in the line will run back down and into the modulator leaving only residue on the inside of the vacuum line. NOT PINTS!

How about take two seconds and explain what you are really trying to say with the see drinking straw comment!

You are sadly mistaken if you think it takes a lot of transmission fluid to make smoke. Try it. We used to start fires with it before EPA regs were invented. Signs of a mispent youth. 

The first time there was a TON of smoke. The second time was Much much less, and I got a little bit further. I called the shop, and he said there may have been some "unburnt" fluid on the bottom of maifold that was not burning off driving locally because it never got hot enough. He said at the higher rpm, it gets hotter so it may burn the rest off. I was able to drive it back home at 40-45 mph w no more smoke. We will see what happens. What do you think about his theory?

Thanks