Moss box 2nd gear synchro available?

I have a ‘64 3.8 E-Type roadster. Is a second gear synchro assembly made by anyone?

@Erica_Moss or @angelw will have your answer.

There is no assembly really. There is a synchro cone machined right onto second gear itself, and there is a synchro sleeve with an inverted cone cut into it. The two meet and synchronize the relative rotation. Moved farther, the operating gears meet and mesh.



So far as new goes, the only place I’ve seen advertise new Moss gears is Welsh, and prepare your wallet because it will probably be over $1500 for these two parts. The best bet is a knowledgeable breaker who can evaluate condition. I had good luck with a seller on Ebay named Morse in the UK.

Your other option is to learn to be proficient with rev matching and double clutching. I drove mine that way for 23K miles with no major grievances.

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I wonder if the cone on 2nd gear could be coated with bronze to replace some of the worn material. Just a thought.

Nah it would wear off in a jiff. the only way to make a used, worn one work better is to machine new synchro grooves into it. It isn’t really worth it though. The fellow from Morse found me a low mileage one for like 150 bucks or something. It just might require a new locking washer of the correct size to result in 2-4 thousandths float.

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In theory… Lapping the parts will also improve performance. It is important to keep in mind that the Moss box was NEVER a slick-shifter, even when brand new. This was probably the most common complaint with the E-Type when it first came out. The Moss gearbox was designed in the '30s for one-ton trucks, not cars. It’s primary claim to fame is its virtual indestructibilty. The gears are made out of some kind of unobtanium that can withstand an incredible amount of abuse, but the synchros are poor on their best day. It does not work well, even compared to its contemporaries, but it is virtually un-killable. The trick to driving with a Moss is to not be in a hurry when you shift. Rathing than shifting from one gear to the next in a single motion, you pop it into neutral, wait a good half-second, or more, then push it gently into the next gear. When down-shifting, you pretty much MUST rev-match to make it go in quietly.


Good work Ray I didn’t know any of that history but I don’t have a Moss box either

Erica, I have not had a Moss box apart, so I am asking the questions:
You show the sleeve and the second gear. And you show the two cones. If I understand it properly on this Moss box, the sleeve slides and pushes against the second gear. The friction getting the two to reach the same speed so the first gear (not as “first gear” but as and engaging component) can engage second gear without clashing. Not mentioned are the springs. The manual gives a spec of 62 to 68 pounds of force to slide the first gear over the sleeve. If seems this force created by the springs is what determines how hard the synchro sleeve presses against the second gear, and thus how quickly the two reach the same speed. Therefore, if the springs are weak and not shimmed per the manual, then the synchro action would be weak. Have people found the springs to be weak and thus contributing to poor shifting?

I hadn’t thought of it in those terms but yes, the springs determine the breakaway force required before the outer gear separates and begins its final travel towards engagement. There is no direct connection between the synchro sleeve and the gear selection fork, only a connection via intermediary spring tension. So too weak a force could definitely impede the synchronization effect. In the opposite case of over shimmed springs, resulting in too strong a release, it would probably result in better synchronization but premature wear to the synchro cones, and stiffer shifting for the driver.

Calibrating it is fairly straight forward. I took a cue from Nick, and placed the gear assembly in a plastic zip lock, along with a wood shim under it that allowed the gear to separate without traveling so far that it allows balls to escape. Then I put it on a bathroom scale and pressed repeatedly, noting the value at separation. The results were fairly consistent plus/minus a couple pounds. I would definitely measure it, and not just presume it’s good enough.


Thanks, it seemed like that was what was going on, but as I said, I never had one apart.

It seems to me that the purpose of those springs are to hold the transmission in first gear so that it doesn’t slip out on its own. In these threads, I have seen many different suggestions for oils that may aid in the 1st to 2nd gear synchronization. I’m trying to choose between Redline MTL or MT90 or Millerol 50. All of which have been mentioned. Any thoughts?

From what I can tell, the shift fork has detects to help keep in gear. And the ones that we were discussing here may also add to that as you say, but they are critical to proper synchro operation.

Thanks Tom. I would assume that Vintage Jag replaced those springs.

there was a guy in Victoria, Australia (which is where @angelw is located) that machined parts for Moss gearboxes

This was between 20 and 30 years ago.
I spoke to him but he would only offer a full rebuild service and would not supply any parts

Sounded like he had more than enough work on, and wasnt interested in doing anything he didnt want to do (at that time racing older vehicles with Moss boxes was still taking place :smiley:)

Don’t know if that was Bill, or he may know who I am talking about,?
He did not sound like a young fella so may be out of the game by now

He may have advertised in Australian Jag Magazine, or I would have got his number of a Jag Club member