TR4/4A I'm back to the well of knowledge - TR3/TR4/TR4A clutch-transmission confusuion

[twigworker]

Here is a curve ball for you...

I am stumbling with the installation of a clutch and related stuff on a TR3 and I need your wisdom.

I first found that the release bearing sleeve that just came in from Moss, the brass one for speced for a TR2/TR4 would not fit properly onto the input shaft support tube that protrudes forward from the transmission case, and that lead me down another road or two.

The sleeve WILL go on the tube but it isn't an easy sliding fit and it should be a nice smooth sliding fit.

The sleeve that came in yesterday is Moss #596-010 and that shows for a TR2 - TR4

The clues...

The transmission appears to be from a TR4 but it might be from a TR4A as it is a four synchromesh unit. For reference the number cast into the main case is 306812. Below that is V2947.

Also for reference, the factory Triumph parts book says that the main case number for a TR3 would be 301039 as that is what is given in the Triumph parts catalog. I do not have a factory parts book for the TR4 or TR4A.

Could it be that I need Moss #596-026, sleeve for this transmission?

Also...

I have the clutch kit ( pressure plate - disc - release bearing ) from Moss, number 593-055. That shows in the Moss catalog as being for a TR2-TR4.

Do I need the #596-030 kit as shown for a TR4A to go with this transmission? If so see my note above regarding the sleeve.

More...

The pressure plate in my kit appears to fit well with the flywheel that is on the engine, but there are two pressure plates listed by Moss. One is the TR2-TR4 unit #593-000 and another #593-010 for the TR4A. Similarly, the disc for a TR2-TR4 is listed as #591-000 and the one for a TR4A is #591-010

In short, if the transmission can be identified by the case number noted above as being out of a TR4A do I not need the different clutch parts and sleeve?

Jack

 

[twigworker]

Yep, I know how to spell confusion, but I can't type well!

Jack

 

[TR3driver]

The front cover of the transmission (where the sleeve rides) was the same diameter across all TR2-6. If your sleeve is too tight, then most likely it is not made correctly. There is an article on the Buckeye Triumphs site that talks about this exact problem and gives dimensions. Since it almost fits, I'd just sand the bore until it does slide easily.

The only dependency between the clutch and gearbox is that the later diaphragm clutch (TR4A-6) requires a slightly shorter front cover on the gearbox. Sorry I don't have the measurements handy, but I can look them up later if you need them. If you trim the front cover (I used a hacksaw) then the early front cover will work fine with the later clutch. The later (or shortened) front cover will also work with the early clutch. ST did not see fit to change the part number, but the longer cover will interfere with the fingers on the late clutch and tear things up the first time you try to use the clutch.

In short, it sounds like all of the components you have should fit fine, the only problem is that the new sleeve is a bit small inside.

Personally I'd probably reuse the old sleeve and return the too-small one to Moss, but I'm funny that way. Defective new parts are unfortunately common these days; mostly I think because the traditional manufacturers have gotten out of the tiny vintage Triumph market and the new smaller manufacturers haven't quite got things worked out right yet. Being located in Asia doesn't help, either, especially when trying to make inch parts on metric tooling.

PS, although I'm now using the later clutch, I did originally keep the original clutch when I first installed the TR6 gearbox that I'm running now. There were some other minor adaptations to fit the slightly larger gearbox in my TR3A (and now TR3), but when I converted to the later clutch the only change to the gearbox was to trim 3/8" or so from the front cover.

 

[twigworker]

Thanks tons Randall !!

So what I think that I am hearing from you is:

1: That I should just hone the sleeve until I feel comfortable with the movement. This car came on with NO transmission or clutch. The transmission was supplied later as a the four synchro unit (TR4A ?) and it came without a sleeve, hence the new one in that is in question.

2: I have the aforementioned release bearing, TR3, that came with the kit and that should press onto the new collar and work with the rest of the kit?

3: The pressure plate that came with the kit is of the three finger variety as opposed to the diaphragm style, and that should work just fine along with the supplied disc?

4: If in fact this is a TR4A transmission, are you saying that it has a short or a long front housing nose? And if it is a long nose it will foul the pressure plate fingers?

Thanks again, Jack

 

[titanic]

The Moss catalog has a page near the front that shows the location of the serial numbers on the transmission. The 3 synchro TR2-3A has the number on top of the raised boss on the left side of the case and is prefixed TS. On the 4 synchro box used on the TR3B-4A, the number is located on the top of the clutch shaft boss (left side) and will be prefixed CT for TR4-4A. If it is a TR6 box, the prefix will be CD,CC, or CF, depending on year.
The snout that is used with the diaphragm clutch is 2", the one on the earlier 3 finger clutch is about 2-3/8".
Berry

 

[TR3driver]

Thanks tons Randall !!

So what I think that I am hearing from you is:

1: That I should just hone the sleeve until I feel comfortable with the movement. This car came on with NO transmission or clutch. The transmission was supplied later as a the four synchro unit (TR4A ?) and it came without a sleeve, hence the new one in that is in question.

Ah, I see. Yes, that is exactly right. Be sure to clean it afterwards, to remove any abrasive.

2: I have the aforementioned release bearing, TR3, that came with the kit and that should press onto the new collar and work with the rest of the kit?

Yup, should do.

3: The pressure plate that came with the kit is of the three finger variety as opposed to the diaphragm style, and that should work just fine along with the supplied disc?

Yes, if it's the larger TR2-4 disc. Actually would probably work OK with the smaller TR4A-6 disc, but I wouldn't put it together that way.

4: If in fact this is a TR4A transmission, are you saying that it has a short or a long front housing nose? And if it is a long nose it will foul the pressure plate fingers?

If it is a 4A transmission, then it should already have the short nose. But either one will work with your early clutch setup.

 

[twigworker]

Thanks to both of you guys !

Now, I just can't wait to get up at six AM, feed Kathleen her breakfast, feed the dogs and run up to an eighteen degree shop where I will be able to freeze both my butt and my fingertips off.:eagerness:

Seriously, Thank You ! Jack

 

[HerronScott]

1: That I should just hone the sleeve until I feel comfortable with the movement. This car came on with NO transmission or clutch. The transmission was supplied later as a the four synchro unit (TR4A ?) and it came without a sleeve, hence the new one in that is in question.

Jack,

Note that the TR4 transmission was synchromesh in all 4 gears as also.

Scott

 

[twigworker]

Yep Scott!:wink-new:

When this transmission came in, it was supposed to have been overhauled, but I ended up going completely through it, lots of expensive parts, and even had to weld up several cracks in the bell housing.

The shift tower railing was a bitch. I don't think that the engineers ever really expected to have any work done up there, but I just gritted my teeth and beat them at their own game.

Jack

 

[RC64]

Thanks to both of you guys !

Now, I just can't wait to get up at six AM, feed Kathleen her breakfast, feed the dogs and run up to an eighteen degree shop where I will be able to freeze both my butt and my fingertips off.:eagerness:

Seriously, Thank You ! Jack

Six AM... I have my doubts... various serious doubts... :friendly_wink:

Rick...

 

[twigworker]

Just for the record...

Thank you, especially Randall, for the prompt information. A little honing inside the sleeve and drilling for the extra roll pin and all is well in Triumphville. I spent the rest of the day rehabilitating some VERY groady accelerator linkage and installed the radiator and hoses.

This chassis and drive train is coming together nicely and should be ready for the installation of the completely rehabed body in a week or so. The owner tends to lurk here, so I will ask his permission before posting some Triumph chassis porn prior to the body install.

Jack