Cruise-O-Matic Questions

[simplyconnected]

I'm still stumped on this transmission noise... ...The old-time transmission guy swears the noise is not coming from the transmission but rather the drive line. I don't know what else to check...

Huh? There are a HOST of ways to eliminate driveline component culprits. You leave a lot of description out of your symptoms and all we know is what you write. When you shift, is your foot on the brake? Is the car at a dead stop? I could go on guessing all day but YOU have to do the tests.

You live in the wonderful state of PA, where hills and mountains are all around. Try parking on an incline, shut the motor off and keep your feet off the pedals. Now, roll all the windows down, shift out of park and listen as the car starts rolling.

Another test I would do is to pull one rear wheel off the ground and roll the tire by hand with the engine off and the trans in park. If any mechanical parts are tight you will know right away. Then, start the engine, apply the brakes and shift into gear. SLOWLY let off the brake to allow the tire to spin.

Test both rear wheels separately.

You have to be the eyes and ears. If you're unsure of yourself, use a cell phone to make short video clips. This process of elimination will narrow your cause. As it stands right now, we cannot tell whether your noises are caused by rear or front wheels. - Dave

[MikeL]

In response to your request for more information about the noise my car is making, I am providing the following details:

-The car has only 20,000 original miles and I have owned it for 15 years without hearing this noise before.

-The noise occurs immediately when shifting from Park or Neutral into Reverse with the brake applied. Note: the car is not moving at all when the noise occurs.

-Other than the noise, the car operates perfectly. The transmission shifts great, no slipping and the car drives with no strange sounds.

-The noise does not occur if the car is shifted into gear without the brake applied.

-The noise is intermittent. If I shift it 10 times, I might hear the noise 2 or 3 times or not at all.

-The noise can vary in loudness and duration. At most it lasts about half a second.

-The noise seems to be a sound caused by two surfaces rubbing together similar to what you might hear if you put the car in gear with the parking brake lightly applied.

Here is what I have done so far:

-Checked the motor and transmission mounts. Motor mounts have some age cracks but appear sound. I intend to install new ones just to make sure.

-With the hood open, I ran the engine and shifted into Drive and Reverse while watching the engine. There seemed to be equal movement in both directions. Increased the RPM a little and did the same test, still OK.

-Replace the transmission mount. It was somewhat deformed but not really bad. This did not help with the noise.

-Tightened all the rear axle mount hardware and checked to see that everything looked OK. No problems found.

-Jacked up the rear of the car at each side with the parking brake off and forcefully rotated the tires back and forth. I did not find any excess play or unusual noises.

-I put the car in reverse with my foot off the brake and started backing out of my garage. My driveway goes up hill after a short distance. When the car encountered resistance and slowed down, I shifted into neutral and let it coast back down. I repeated this many times at different speeds and I could not duplicate the noise as long as the brake was not applied when I put the car in gear.

-I took the car to a good transmission shop and the owner who has 45 years experience checked things out and swears there is no transmission problem.

Here is what has me confused:

The noise I hear definitely sounds like it is caused by two surfaces sliding against each other. When put in gear with the brake firmly applied the car is not moving. A bad U-joint or broken engine mount would make a distinctive sound which is unlike what I am hearing. The slipping sound I get last about half a second which seems like it could only come from something moving (inside the transmission?).

I hope that this has provided enough information to assist in diagnosing this problem. Any input or suggestions will be greatly appreciated.

[Frango100]

So it seems that your problem is related to the brakes. Where all brakes checked for any loose component? If you only set the parking brake and then put in gear, do you hear the noise than?

[simplyconnected]

...-The noise occurs immediately when shifting from Park or Neutral into Reverse with the brake applied. Note: the car is not moving at all when the noise occurs.

...-The noise does not occur if the car is shifted into gear without the brake applied.

...-The noise seems to be a sound caused by two surfaces rubbing together similar to what you might hear if you put the car in gear with the parking brake lightly applied.

...-I put the car in reverse with my foot off the brake and started backing out of my garage. My driveway goes up hill after a short distance. When the car encountered resistance and slowed down, I shifted into neutral and let it coast back down. I repeated this many times at different speeds and I could not duplicate the noise as long as the brake was not applied when I put the car in gear.

...-I took the car to a good transmission shop and the owner who has 45 years experience checked things out and swears there is no transmission problem.
...The noise I hear definitely sounds like it is caused by two surfaces sliding against each other. When put in gear with the brake firmly applied the car is not moving...
...The slipping sound I get last about half a second which seems like it could only come from something moving (inside the transmission?)...

I agree with this being a brake noise (but not a problem). I have never heard motor mounts make a noise like this and I am surprised you changed any of your mounts.

You need a better understanding of how drum brakes work. More specifically, what stops the shoes from rotating around with the drum??? Shoes must naturally 'float' so they can move but they are 'captured'. How does this change with tight or loose brake adjustment? Why don't disk brakes share this 'problem'?

'Brakes' use the lowest technology on your car but we depend on them the most and we almost take them for granted with full confidence they will perform every single time over millions of cycles of operation.

I'm going to stick my neck out and suggest this noise may be created with your FRONT brakes because they do most of the stopping. Furthermore, you may find this noise comes when alternating between forward and reverse motion while using your brakes in both directions.

When I do a (drum) brake job, I include lubrication on the back-plate brake pads. This is a special high temp lube, usually silicone-based, and applied sparingly. More is not better, here. I suggest you inspect and lube your pads. If deep grooves are worn into the back-plates, the car is certainly older than 20k miles. The grooves may be filled-in with weld and ground flat, restoring to 'new' condition.

If the car truly has 20,000 miles, the brake pads will look great and will only need the lubrication. Stay out of deep water. - Dave

[MikeL]

Sorry guys, but I must disagree about the cause of this noise.
I just went out and tried the car again. Twice, I got the noise when shifting into reverse. It was very pronounced and I actually felt a shudder coming up through the seat. The car was not in motion when this occurred. Also, for the first time I got noise while shifting from Neutral into Reverse with my foot off the brake.

I appreciate your efforts to help diagnose this problem from a distance and I understand the difficulty of trying to do this without actually hearing or feeling what the car is doing.

I realize that I am not an expert but I have been working on old car for over 40 years and I do know some things. I've been trying to solve this problem for a few weeks now and based on my latest experience I think the problem lies in the transmission.

[Frango100]

Was your parking brake still on when you got the noise?
You told that your transmission guy, with 45 years of experience on transmissions, didn´t think the problem was related to the transmission. Didn´t the problem occur when he was diagnosing?

[MikeL]

No, the parking brake was not on. I wasn't present when the transmission shop was looking at the car but the owner did tell me he heard the noise. He also suggested I should replace the transmission mount which I did.

I have been hearing this noise for several weeks now and I am positive it is not coming from the brakes. I believe the noise and the shudder I felt originates inside the transmission possibly from the reverse band or reverse/high clutch slipping.

[simplyconnected]

Mike, nobody is questioning your mechanical ability but I will offer you a challenge just to get your restoration juices going, so don't take offense but rather, prove me wrong. We're here to help and we only have your written word to go by. I appreciate that you have many years of experience but I also realize that over the course of a few weeks, you are still stumped. Many of our members have restored C-O-Ms including myself (me, not a hired mechanic) (CLICK HERE for my rebuild).

You gave us test results but I think you are saying the new tests contradict the first ones.

Nobody on earth is as cheap as I am which is why I refuse to throw parts at any problem. It's also why I do my own work. It may be that you will find the culprit but not before accumulating a bushel basket of good parts that cannot be returned. My style is different.

Can you make a five minute video? While you are simulating the fault, have someone hold your cell phone or camera outside the car. Video with the camera (phone) low and near each wheel as they go around the car. It's important to show the ground and at least one wheel at the same time, just so we get a reference.

During the video, we can tell if the brake is applied because the car body usually tugs forward or backward as the wheel stands still or you can announce the condition while recording. When done, send the video to me (simplyconnected@aol.com). I will post it for everyone to see. If you need to make a few videos, that's perfectly alright. Let's get to the bottom of this.

Back in '61 my father ordered a new Pontiac Safari (station wagon). It came with a vibration that nobody at the dealership could ID. The car went to Pontiac Motor Co., (Pontiac, MI is ten miles from our house) where factory mechanics discovered, the exhaust pipe sometimes vibrated against the body but only under certain load conditions. Most problems have simple solutions like this one. Different eyes see things differently. - Dave

[bird 60]

Hi Guys, I've got a feeling that we're barking at the wrong tree.
Mike says that the noise comes on when placed in Reverse, from Park or Neutral, with the foot on the Brake without the car moving. If it's a BZZZZZZZ or GRRRRR sound, my T Bird & many others make that sound in Reverse for a short time. As far as I know it's nothing to worry about. If it is, this topic has been covered a few times in the past. I'm crossing my fingers.

Chris.....From OZ.

[MikeL]

I think I should just end this discussion here. I've wasted enough of everyone's time trying to figure this out.

I may have given a wrong description of the noise by saying that it was similar to what you would hear if put the car in gear with the parking brake on. That was the best way I could describe it at the time. Now after hearing so often, it is more like a "rrrrrrrtttt" sound that is very pronounced and could last almost a second.

This sound combined with the shudder I felt while the car was completely stationary indicates to me that the transmission is the likely source of the noise.

I plan to take the car back to the transmission shop and try to duplicate the sound while the owner listens. Once I find out what the actual problem is, I'll post here again so there can be some closure to this issue.

[Yadkin]

...Twice, I got the noise when shifting into reverse. It was very pronounced and I actually felt a shudder coming up through the seat. The car was not in motion when this occurred. Also, for the first time I got noise while shifting from Neutral into Reverse with my foot off the brake.

This could be debris inside the torque converter (happened to me) or debris or a chip on the clutch plates. If it were me I would do a transmission flush, drain the pan and converter, install a new filter and fluid and hope for the best.

[sidewalkman]

This could be debris inside the torque converter (happened to me) or debris or a chip on the clutch plates. If it were me I would do a transmission flush, drain the pan and converter, install a new filter and fluid and hope for the best.

That is what I would do as well. Sounds like you might have some debris floating around and it only makes a sound when it comes into contact with something else.

Easy and cheap and probably overdue to drop the pan in any case. But check the screens.

[MikeL]

I appreciate the additional suggestions, but I don't think it is a problem with the converter or debris.

Because the noise only occurs when shifting into reverse and the transmission behaves perfectly at all other times, I think the problem lies somewhere in the mechanical components and hydraulic actions that come into play when reverse gear is selected.

I just drove the car again today. When it was cold, it would make the noise repeatedly. Once warmed up, no noise after many attempts. This is another clue.

I changed the fluid and filter when I got the car in 2001. It had only 17,000 miles at the time and had not been driven since 1967. Everything looked beautiful inside the transmission at that time. The transmission has been fine for 3500 miles and 15 years until it suddenly developed this problem a few weeks ago.

I think what is possible is that an o-ring or seal has gone bad and is causing erratic operation of a clutch or servo. I don't want to tear into the internals or the transmission while laying under the car so it will take another visit to the Transmission Shop to get things fixed.

[sidewalkman]

I'll tell you the story of my transmission, might give you hope.

I bought the care, the tranny had grenade the end shaft piece likely after a few reverse to forward while moving maneuvers by the PO but they installed the identical transmission used shortly before I got it, the guy said it was low miles but had sat for years.

Long story short it would drain back out of the converter so every morning it had to warm up for 5 minutes or it slipped to the point of the car not moving. I bought some of the lucas stuff to rejuvenate warn seals, drained and refilled the tranny and added the stuff, about a litre. BTW the kick down never worked and it made odd noises going from park to drive etc. I drove it around for about 500 mile all the time trying to dial in the linkage. Go too far one way slips all the time, too far the other and it shifted like a bomb going off and wouldn't go into reverse without a ton of time moving the shifter just so but over time the drain back went away as did the noises except for a weird buz that goes away as soon as it goes into gear. Then finally I found the sweet spot on the linkage and a transmission shop put it on a hoist and tightened the linkage at the tranny and now its like a new car. the point being try some of the Lucas stuff and drive it, it takes about a solid month for the seals to swell up again but it did make a huge difference.

[Yadkin]

I changed the fluid and filter when I got the car in 2001.... The transmission has been fine for 3500 miles and 15 years until it suddenly developed this problem a few weeks ago.

If your fluid is 15 years old it should have been changed about ten years ago. These transmissions are vented to the atmosphere and moisture gets in, fluid gets wax deposits every winter...