TR4/4A Overdrive

[KVH]

I'm going to show my ignorance: I posted a message about a rattling sound from the rear of the car, which I was certain was coming from the mufflers or tail pipe. But, I can't find anything wrong. The noise was louder and progressed with engine rpms. I'm almost certain the noise was also at stop light idling, but if, by chance, it was only during movement, would I be correct to conclude that a tin can rattling sound could not possibly be coming from my rebuilt overdrive?

I'd think I'd have an explosion before anything could be rattling around in the OD like that, and I can't imagine what that could be, other than a bushing that sort of worried my since I was told they frequently fail--the one in the planet gear assembly.

thx

 

[NutmegCT]

Don't worry about showing ignorance. I do it all the time!

Is the rattling only when the car is in motion?

Tom

 

[glemon]

It still sounds like a muffler problem to me, did you try to kind of jimmy it around by hand to see if it was hitting anything or makes sound when moved? Does the sound change directly proportional to engine RPM, then probably engine/flywheel/clutch, if more proportional to speed tranny and driveline back. I don't think your overdrive would make any noise while the car is sitting, does it change when you push on the clutch pedal? throwout bearing? generally saying try as many different things with the car as you can, listen for changes on the noise, and think about how the various parts work and it can narrow down your search for the source. I don't think the O/D should be making any noise when the car is sitting.

 

[TR3driver]

I learned long ago to not say anything like that is "impossible". When my first wife moved to CA (before we were married), we brought her old Torino along. She warned me that sometimes, the throttle would drop to the floor "all on it's own" and you had to mash the brake "really hard" to get it to stop. I scoffed, saying that was impossible. It might stick, but couldn't just drop all on it's own. Then I drove the car and, sure enough, it would go full throttle for no apparent reason! Definitely attention-getting, as it turned out the previous owner had modified it with a 351 and lower rear end gears; and it only happened in first gear.

Certainly the OD is not turning when you are stopped, so no noise from inside it while stopped. But, if the racket is only while moving, then it is at least a possibility. Still unlikely, I would say, but possible. However, the thing in the planet carrier that seems to break (a thrust washer, not bushing) doesn't seem to cause unusual noises. Mine has broken several times now, and I didn't notice any noise. Last time, it didn't even cause a problem until the bits from the thrust washer started getting jammed in the pump valve, which kept the OD from working. When I pulled the accumulator cover to inspect, I found a kind of coarse gold paste inside.

I would certainly look everywhere else first, particularly in the area of the bell housing (assuming you've already exhausted the exhaust possibility) (pun intended).

 

[KVH]

I pulled the mufflers to check them for broken insides and I'll report back whether the noise is gone or just while moving--I just can't recall but I know it was markedly louder when accelerating and when engaging the clutch. Very loud on engagement. But it just sounded too tinny and rear end to be the clutch.

 

[NutmegCT]

I'd think the first test would be - does it make the sound when revving the engine with the car stationary. Seems that might help isolate the cause.

How old and rusty are the mufflers? Rusty insides can be loose and rattling around.

Tom

 

[JerryVV]

Remove the tin flywheel cover and see if the noise goes away. Been there, done that.

 

[HerronScott]

I learned long ago to not say anything like that is "impossible". When my first wife moved to CA (before we were married), we brought her old Torino along. She warned me that sometimes, the throttle would drop to the floor "all on it's own" and you had to mash the brake "really hard" to get it to stop. I scoffed, saying that was impossible. It might stick, but couldn't just drop all on it's own. Then I drove the car and, sure enough, it would go full throttle for no apparent reason! Definitely attention-getting, as it turned out the previous owner had modified it with a 351 and lower rear end gears; and it only happened in first gear.

Randall,

You can't leave us hanging. So what was the cause?

Scott

Scott

 

[KVH]

Remove the tin flywheel cover and see if the noise goes away. Been there, done that.

I plan to work on this today and find that darn problem. My muffler guy looked at my mufflers and told me that removing them didn't help identify the issue because he needed to hear the car run, but he did say that he highly doubted it was the mufflers, themselves. He examined them and said they were nothing but beautiful Triumph mufflers. He's about 63 years old, so I liked hearing that.

He's suspecting I'm missing a loose clamp or a touching part. I'm looking again.

HOWEVER, what's this about the flywheel cover. I was under the car about to take that off and stopped myself, certain that if something happened in there I'd have way more problems than a loud tin can rattle. Are you suspecting something popped off my throwout bearing, or the shaft?? (btw, I'm told my flywheel is some lightened kind)

 

[NutmegCT]

So - do you hear the noise when the engine is running and reving, regardless of gear selection, when the car is stationary?

 

[TR3driver]

The flywheel cover is irrelevant; no worms inside. It just serves to keep the bottom of the bellhousing from scooping up gravel and such from the road. And it does sometimes rattle annoyingly, especially if there is an undetected crack from metal fatigue or a loose bolt. Worth a try. But if the rattle happens at all engine rpm, I'd expect to find something obviously loose.

The Torino's problem turned out to be a broken motor mount. The throttle linkage on that car was a bell crank on the firewall and a long rod to the lever on the carb. (Not sure if that was original, or a DPO-ism.) As long as the engine was sitting down on the broken mount, there was no problem. But, if it rolled over to the side, it would stretch the throttle linkage and pull the throttle open. It took only light throttle plus a left hand turn to start it moving; or a bit more throttle in a straight line (in first gear) then of course once the throttle started to open a bit more, the engine torque would keep pulling further, opening the throttle more and so on. Actually kind of fun if there wasn't any traffic in front of you! (Or any cops around to hear the squealing tires.) Once the transmission caught 2nd gear at about 40 mph, then the engine would fall back and everything would be fine.

Don't recall if I ever changed that mount or not; but we never used the car much and eventually let it be towed away. I had already signed on a new car when she moved out here (although it didn't come in for some months), and even the $300 POS that I had been driving was better than that Torino.

 

[JerryVV]

I plan to work on this today and find that darn problem. My muffler guy looked at my mufflers and told me that removing them didn't help identify the issue because he needed to hear the car run, but he did say that he highly doubted it was the mufflers, themselves. He examined them and said they were nothing but beautiful Triumph mufflers. He's about 63 years old, so I liked hearing that.

He's suspecting I'm missing a loose clamp or a touching part. I'm looking again.

HOWEVER, what's this about the flywheel cover. I was under the car about to take that off and stopped myself, certain that if something happened in there I'd have way more problems than a loud tin can rattle. Are you suspecting something popped off my throwout bearing, or the shaft?? (btw, I'm told my flywheel is some lightened kind)

Look for any evidence that something is rubbing on the cover. In my case the cover was bent slightly and the ring gear bolt heads were rubbing when I either depressed the clutch or was running, I can't remember but I think it went away when I depressed the clutch because the flywheel will move slightly moving the bold heads away from the tin cover. Nothing inside came loose.

Contrary to Randall's comment it is relevant if something is rubbing against it. It makes a lot of noise.

 

[KVH]

I think I found the source--a bad muffler. I posted what I found under a related, earlier post I had about "Noise from the Rear." I think I've cleared my worries about the Overdrive, though if that humming comes back after I fix the muffler and exhaust system, I'll be back for more advice on this subject also. thx