TR4/4A Transmission noise - intermittent

[Popeye]

Hi all,

TR4A, overdrive transmission rebuilt by John Esposito at Quantum about seven years ago, but not run until this summer when I finished assembling the car. About 2,000 miles on it since completion.

I am getting an intermittent noise from the transmission: it sounds normal if I drive gently, shifting below 3,000 rpm. However, if I wind the engine up to 3,500-4,000, I hear a nose that sounds like marbles in a glass jar. After winding up to 3,500, the noise is present above 1,500 rpm, ie all the time when driving. Quiet at idle. The noise is not terribly loud, but loud enough to hear over everything else. If I just poke the clutch, the noise goes away (but returns upon release).

If I let the engine idle a little - sitting at a red light, the transmission is again quiet if I shift below 3,000. Wind the engine up again, marbles…

Thoughts?

 

[KVH]

Over the years I've started many threads that one way or another mentioned that annoying marble knocking sound when I accelerate. It was never my transmission, though the noise certainly sounded like it was coming from the bell housing. Not the problem, despite the sound. I'm not saying yours isn't, because I'm not driving your car, but the issue was poor timing. I was either too far retarded or too advanced, and I just can't recall which. That same marbling, gathering, gravelly sound went away or greatly abated with proper timing. You must have a good distributor, without shaft wobble, points set correctly, and timing accurate. I hope that helps. If might not, but when someone talks about marbles in the transmission, I have no trouble hearing it--and understanding the frustration.

 

[Popeye]

Interesting, thank you. The distributor should be OK (rebuilt be Advanced Distributor) - but the timing (set by me) might be suspect! I will have a look…

 

[NutmegCT]

Just my two cents - but isn't it possible you're getting the rattling sound from the chassis, when the car hits a certain speed? Part of the drive train touches part of the chassis/suspension, and doesn't stop hitting it until the car slows.

Tom M.

 

[mctriumph]

KVH is on this one,
There is no such thing as an intermittent tranny noise. It may get louder under different loads
but it is always present. Look to timing/gas for a detonation issue. On thing we all seem to forget,
is that after a few weeks of setting, premium gas has lost her ginger( as they used to say)
A good friend of mine lost a motor to a high speed detonation caused by old fuel . Getting
a bit deaf I should say.... and expensive.
Mad dog

 

[CJD]

Check your starter. If the retaining ring on the pinion gear fails or loosens, then the pinion will slide back into the flywheel ring gear, but only on hard acceleration. It will eventually get knocked back forward, only to happen again on the next rapid acceleration.

 

[charleyf]

I am with the "timing is off group". I had this on my TR3B and it was called pinking. But pronounced pinging. Reset the timing.
Charley

 

[sp53]

You say the noise goes away when you push the clutch a little; makes me think throughout bearing or something broke inside the clutch or throughout bearing. Just guessing ---How high up is the clutch pedal in the car? I like everyone’s suggestions and curious what the problem is. The other suggestions would be easier to look at for sure. Maybe pull the starter and give it a shake. I like the distributor set up on these cars because the top of the dizzy pulls free from the pedestal making replacement easy for testing.

steve

 

[Popeye]

A big thank you for your ideas!

1. distributor: definitely I will check, but the car ran “quietly” (a relative term!) for 2k miles before the noise started. I did not make any changes to the timing.

2. Chassis resonance: the chassis definitely makes noise, but the noise I am hearing is engine speed dependent, not road speed. And it goes away. Having said this, eliminating various clunks and rattles is an ongoing project - this winter I will thoroughly review all fasteners, having put a few miles on the newly assembled car.

3. Starter. This one is interesting. I had the starter (and generator) rebuilt by a wonderful proverbial “old man in a messy small shop” who seemed to know his stuff. I installed the starter without a second thought, and has worked very well.

4. Transmission. I’ll have to check on the clutch pedal travel. It is “high”, but fully disengaged (ie transmission engaged) when I release the pedal. (there is slack in the clutch linkage when the pedal is up.)

i plan on having my mechanic take a listen, but depending on how soon he is available, I might have a look at the starter in the meanwhile. If the transmission needs to come out, I’ll probably do the interior disassembly/reassembly and let him do the mechanical work: for fear of repeating a mistake - he is very much on-board with my wrenching, and a great teacher.

 

[sp53]

I guess my first thought was if the clutch leakage is way lose and the pedal is way high perhaps the TB is rubbing on the clutch forks at high speed making the marbles in a jar noise. I do like that metaphor.

steve

 

[charleyf]

Check the gap in your points.
Charley

 

[CJD]

While pulling the starter, also remove the flywheel cover and check for loose bolts, nuts, etc in the bell housing. One of those "while you're there" things to give you a piece of mind that something isn't flying around the flywheel.

 

[TFB]

Are you sure its not the common shift lever rattle?Before the fix mine acted like that.The heavier the acceleration the louder the rattle.Touching the clutch would take the load of ftrans.I know its a long shot but try holding the lever and see if noise lessens.
Tom

 

[Popeye]

Again, a huge thanks to everyone for ideas and suggestions. The shop drained the oil and found lots of metal stalactites on the magnetic plug, plus a shimmer of metal on the drained oil. He believes he also saw some bits of gear teeth.

Ugh. The fun of “sorting” a fresh restoration! (Actually it is fun, especially now that it is getting too cold to drive in the northeast!)

I’ll take out the transmission and drop it off at Quantum next week. I’ll keep everyone posted as to progress!

 

[NutmegCT]

Yikes - a fresh rebuild that needs rebuilding. Not fun.

Hang in there - eventually you'll be enjoying the open road, without the rattles.

Tom M.

 

[Popeye]

Yikes - a fresh rebuild that needs rebuilding. Not fun.

Hang in there - eventually you'll be enjoying the open road, with the rattles.

Tom M.

Yep… but it’s all for the better! The good news, I have a non-OD transmission that I might install while this one is been repaired.

 

[mctriumph]

They used to call it "swarf" ,to a certain extent it is "normal" I would suggest a fresh fill and 50 miles
to make the diagnosis firm. Hate to pull a box for no good reason.....
Mad dog

 

[Popeye]

Quick update; I dropped the transmission off at Quantum, and John found considerable wear on several bits. I assume this happened while it was sitting at my mechanic’s shop for a few years… On the floor, and while it was filled with oil, I’m assuming it wasn’t rotated much.

Bottom line, I’ve got a rebuilt transmission, which I installed over the past two weekends. I took a test, drive yesterday, and everything runs beautifully – OD and all.

And having the car up on stands for a few weeks gave me the time to redo the oil pan gasket. I was getting a bit of leakage; not terrible, but I thought I could do better. I flattened the pan holes (which I did not do previously), installed the gasket with our RTV on a glass plate, and reinstalled the pan. Time will tell if I did a better job this time.

 

[sp53]

These oil pans are difficult to seal up for me. Last time I used mylamar and I thought I did my best, but it leaked too much. I thought it might be leaking down through the bolt holes, but I do not know. Next time I am using the piece of class.

Glad you got the OD sorted out.

steve

 

[mctriumph]

The Tr4 trannys suffered from a very iffy counter shaft bearing, they die a horrible death
if they do NOT receive good maintenance. Any sign of "not quite right" in an old Tr4 box
should NOT be ignored ! Park it at once ! The failure of this bearing will destroy the entire
assembly in very short order and take the OD with it too.
Mad dog