Noisy rebuilt Close Ratio gearbox

EJ13784 Hi guys,

I have spent a considerable amount of time trying to figure out whether my close ratio gear box EJ137xx should be noisy or not.
Some say they they were used for racing and then had straight cut teeth, some say something is wrong.
It is more noisy than my previous E type series 2 from 1970 that was never overhauled.

Any ideas?

All my E Type gearboxes sound like cement mixers.

As long as it changes gear and stays in gear it’s probably fine.

1 Like


Thanks for your promot anseelse.

So They sound like cement mixers, the Moss box, the Jaguar full sync from 1964 irrespective of close ratio or standard ratio, etc.?
If I want a silent one, is it then a Tremec type that rule?

I have a Jaguar friend, he cannot decide whether it is OK or not…
Alone with me he says it is bad, when taking to the gearbox resto company mechanic, he says OK.

The mechanic say it is OK. I have found no contaminations in the oil either.

Both has tested the car.

That was comforting.:blush:

Thanks for your feedback.


I replaced the Moss gearbox in my '64 with an early EJ unit during the fairly recent restoration. The synchros were fine and it stayed in gear without issues, but it seemed a bit noisy. I attributed most of the box of rocks sounds to wear in the reverse idler gear and that was confirmed by subject matter experts in the link below. That said, according to source material I have read, Jaguar did change the gear tooth profile to reduce noise when they developed the later wide ratio, sedan focused KE transmission.

After some 900 miles I decided to replace the EJ transmission in my car to a rebuilt KE. It is quieter, but I attribute most of the improvement to the lack of reverse idler gear noise. (I still much prefer the more sporting EJ closer gear ratios).

The dreaded reverse idler gear rattle - E-Type - Jag-lovers Forums


Reverse idler is «new», from New York, found on EBay

My noise concern is primarily the first gear, rest is not too bad.

For me it just sounds wrong.
No debris in the oil either, only a Little on the first gear shift. Which was Redline oil. Now Classic original spec oil.
Change of oil has not changed any sound isssues…

In beginning I was just driving with an open gearbox, no cover, no insulation, nothing around it.

Now I have more or less all covered up.

The gearbox works very good, tight and precise gears, reverse good.
Just that 1 gear noise😳

How much time do you spend in first gear? The first gear in the all synchro box always whines - I believe that it has straight cut gears. If the other gear ratios are acceptably quiet you are probably ahead of the game…

1 Like

If you have a low idle with the EJ box is will be noisy. Bring the idle up to 800 or above it will smooth out. and the rocking noise will diminish or go away.
First gear will whine a bit, not like a Moss box but it will whine. Not sure but I think the manual even has a description of it.


This was very comforting. It just sounds terrible. Other gears are smooth and fine.
Gear changes just very good.

A theory from my Jaguar friend here suggests it is the gear shift striking rod for the 1/2 gear is bent or worn.

He agree with you, drive and smile and be happy…:blush:

1 Like

I never heard any gearbox noise in Tweety…:wink:

Its a helical gear like the rest of the gears in the All Synchro gearbox (including Reverse Gear). First Gear and the Reverse Idler Gear are both driven by the same gear on the Lay Cluster. The probable reason for First Gear being noisy is that any damage to the Reverse Idler Gear will eventually be transferred to the Lay Cluster Gear and First Gear on the Main Shaft.

There will also be more wear on the Lay Shaft at the First/Reverse Gear end, resulting to a slight change in the mesh of the Main Shaft First Gear and the Lay Cluster First Gear, resulting in noise when under load.


1 Like

Wishful thinking at best.

If it were the case, logically, Second Gear would be as noisy as First.

The noise will be emanating from the First Gear mesh of the Lay Cluster and Main Shaft caused by my suggestions in my previous Post.


1 Like

The gearbox, the rebuilt gearbox, is noisier R idle that the engine. Depressing the clutch provides the dramatic change in level of noise.

No, it’s not the idler gear etc but a strange waaa waaa waaa noise most easily heard when shutting the engine off and rolling down the driveway. I’m told it’s mismatched gears?

The box operates perfectly well and I’ve given it some high revving hell just to see if something goes bang……,all is well but very annoying.

Tried different oils too, not much difference between them.

Thus is the original gearbox in my ‘68 S1.5