TR2/3/3A TR3 Transmission Blues

[mcguijo]

Finally gotten around to messing with the engine/tranny on a TR3A I bought. Engine number is around 53000 w/ bolt on ring gear around fly wheel. Tranny, however, is older type that fits long "bullet" type starter. I'm guessing the engine (ring gear) and tranny don't match. /ubbthreads/images/graemlins/nonod.gif What sort of transmission do I need to be looking for for this engine number?

 

[Geo Hahn]

A simple solution to this would be to use a hi-torque starter designed for the later engine (w/ bolt-on ring gear). I believe this starter does not require the bulge in the bell-housing that the later stock starter requires.

An alternative some have used is to poke a hole in the early bellhousing to accomodate the long later starter (can't say I like that idea much).

Finally, and FWIW -- I have used the late engine (w/ bolt-on flywheel) and early (bullet-nose) starter for 25 years without a problem. I am not recommending this but just offering my own anecdotal experience (YMMV).

 

[mcguijo]

Someone else has recommended the hi-torque starter. This is likely the most cost-effective route for me to take. For historical accuracy, however, would I want to match an "all synchro 4-speed transmission" with my engine?

 

[Geo Hahn]

The change in flywheel/starter was introduced at 50001, the synchro was introduced later (TR3B & TR4).

It would take a really sharp concours judge to determine that you had a pre-50000 gearbox on TS53087 (i.e. they would never know).

One thing you said confuses me: "...Tranny, however, is older type that fits long "bullet" type starter...".

The bullet-nose starter is actually shorter than the later starter. That's why it cannot be used on the later gearbox (a bigger bulge was added to accomodate the longer later starter which engages by pulling back rather than thrusting forward. Are you sure you have a pre-50000 gearbox?

Here is an eBay listing that shows the longer bulge in the later bellhousing (couldn't find a pic offhand for the earlier but basically the back half of that bulge isn't present).

 

[mcguijo]

Sorry, I guess I'm messing up my terminology or am simply clueless. Attached is a picture of the type of starter that came off of the transmission (i.e., fits snuggly in bell housing). The facts on the engine and the ring gear remain the same. Hopefully, this starter picture will clear up what type of transmission is on the car.

 

[Geo Hahn]

Yes, that is the early starter. I would be curious as to the condition of the teeth on the pinion as that (rather than the flywheel) is what usually gets beat up if there is a mismatch.

Let me know if you decide you want to sell that starter.

 

[mcguijo]

Just so I understand (I'm slow on the draw). . .the early starter and transmission that I have are a fit (i.e., the later starter with the longer shaft does not fit in the bell housing of my transmission). However, this starter/tranny combo are pre-50000 and thus (for historical accuracy) do not fit the engine/ring gear combo that I have. Potential remedies are to 1) fit current tranny with hi-torque starter or 2) find non-synchro 3 speed transmission whose bell housing fits the longer shaft starter (a transmission that is post 50000 but pre TR3B synchro) 3) leave as is 4) cutting the bell housing option (which I probably won't do). Point #2 is where I need the most insight on.

 

[Adrio]

The starter you have fits the early ring gear. You can do many things to get where you want (though I am not sure I understand where you want to get).
1)If you wish to keep that starter AND go to a 4 gear synchro that is not a problem (only a lot of work, maybe). You need to get the proper ring gear and install it. Then you need to get the full synchro box and install that. This will give you what you want but the tranny will have the longer bulge.
2)If you don't mind going to the more modern starter then you need to buy the late TR3/TR4 starter (or the high torque one mentioned) and install that. As well you need to find a full synchro box with the long bulge and install that. This will give you both the starter and gear box looking like a late car
3) If you want the early starter (like you hae) and the look of the early tranny (short bulge). You may be out of luck. I am not sure you can fit the internal from a full synchro box into the casting of the early short bulge box. If that is possible (some one will tell us) then it is just a question of work. This summer I did a swap of tranny parts from one gear bos to the other case as I needed to have the long bulge case and it only takes a two or three hours and a bit of patience.

 

[Geo Hahn]

Ooooh, now I'm corn-fused.

Do you want --

A correct as original set-up?

Or the easiest way to get something that will reliably work?

If the former, there is only one way to go.

If the latter there are a couple of possibilities depending on how non-original you are willing to tolerate.

Thinking synchro vs non-synchro may just muddy the water. No TR3As came with a first gear synchro. The changes in starter and bellhousing were separate from the change to add a synchro first.

 

[Adrio]

I am glad to see I was not the only one confused. As far as synchro goes though, I would say I don't miss it much. My TR3 never had it and my TR4 had it for 700 miles before I had to switch to an overdrive non synchro. I do not miss the syncro at all. I never shift into first while I am moving and I have developed this second to first while stopped habbit that solves everything.

All that to say, I would not let the synchro thing weigh too much on your final choice.

 

[mcguijo]

OK Sorry. . my first choice would be to go as original as possible. I was simply trying to way my options.

Engine number is TS53400E (which matches with Comm.# of car).

Number off of transmission is 301039 (see attached picture)which I don't believe is the correct transmission for this engine. I'd like to match the correct transmission to the forementioned engine number. . .but don't know what the correct transmission would be.

 

[TRTEL]

I think I've read this all twice and my head hurts. Can't believe that the starter drive could be worth saving if it's been used very long with the wrong ring gear (the late model bolt on type). The only thing I know for sure is that you cannot put all synchro box components in the early trans case. I think Geo is correct on the comm # and the car should have had the later gearbox, but the trans # is stamped on the top edge of that oval shaped casting on the drivers side of the case. The 301039 # is the part number for the case. If the starter is OK you might consider switching to the early model flywheel (with pressed on ring) they weigh a heck of a lot less maybe 8 or 10 lbs. I had one machined years ago to use with the bolt on ring and long nose starter just for that reason. Good luck.
Tom Lains

 

[mcguijo]

Sorry to confuse, frustrate, and otherwise give folks a headache. .I'm low on the learning curve but really appreciate your insight.

Just as a followup, the number off the oval casting is 20XXX (couldn't read the last three digits). Looks like I'll be getting rid of this transmission and hunting for a different one.

 

[sammyb]

Trust me, I know this gets really confusing!!!

On the post-50000 TR3 I recently got, the starter kept hanging and locking the engine. When I pulled it out, it was an early starter (or what I call the "uncircumcised" starter.) I had blindly ordered the later high-torque starter (figuring it was the correct one for the car.)

I pulled the old one out, put the new one in, and got the car running before it ocurred to me that the wrong one had been in there to begin with!!!

 

[TR3driver]

[ QUOTE ]
OK Sorry. . my first choice would be to go as original as possible. I was simply trying to way my options.


[/ QUOTE ]

I'm not sure if this helps clear the waters or not ... original for your commission number would be a 3-synchro box (so no bulge at the rear) but with the bulge to clear the starter drive. Also no dipstick on the top cover, but with a fill (and level) plug on the side of the gearbox. Sorry, I don't have any numbers handy.

The early starter & flywheel will work with the above gearbox, but to really be correct you also need the later starter and flywheel. The starter can be seen with the hood up, so it's more apt to be noticed.

 

[mcguijo]

Thanks for the information. I guess I was getting confused with the concept that "2nd, 3rd, and top" had gear synchronisation while 1st did not and this was called a "nonsynchro" gearbox. Regardless, I think I FINALLY have the concept figured out.

Next question. Know any folks who may have one of these gearboxes rebuilt and ready for sale???

 

[Alan_Myers]

[ QUOTE ]

Next question. Know any folks who may have one of these gearboxes rebuilt and ready for sale???

[/ QUOTE ]

Yes, it can get confusing! /ubbthreads/images/graemlins/confused.gif

Basically, TR2/3/3A had 3-synchro boxes (no synchro on first gear). The guts are not interchangeable with the later 4-synchro gearboxes (TR3"B"/TR4/etc.) because the case is a little longer on the later boxes.

To make it more confusing, there were variations within these: 3-synchro boxes with early and late style starters, press-on and bolt on ring gears, "dip stick" and non-dip stick.

There is some variation in the 4-synchro boxes, too. Later ones have a heavier bell housing flange. Some of the internals were improved, too. The clutch changed between the TR4 and TR4A, too.

Add that *all* the above were built and offered in overdrive and non-overdrive versions, too.

Many of the vendors offer rebuilt gearboxes: The Roadster Factory does their own rebuilds. The last time I checked, Moss and Victoria British import them from a UK rebuilder.

With Moss and VB, you kind of get what they sell you. In other words, the rebuild could be from anywhere in the TR2/3 line, if that's what you specify. You can probably specify the correct starter bulge gearbox, bu that's probably the limit.

With respect to the later 4-synchro gearboxes, when I bought a rebuilt overdrive box for my TR4, I actually ended up with a sedan unit (from a 2000, judging by the serial number), which has the thick flange and beefier internals. That's okay by me, but certainly not original to the car. But, it was over 5 years ago when I ordered the gearbox and I can't recall who I got it from, although I am certain it the work had been done in England. I suspect it was from TRF, before they started rebuilding their own.

If you are seeking a box that's most original to your car, it will likely take some work and you will have to talk to a couple of the companies that rebuild on this side of the big pond. Try talking to John Esposito at www.quantumechanics.com or John Swauger www.the-roadster-factory.com to start.

As you can tell from the discussion so far, all are very similar if originality is not a big concern, certain versions just require the "right" matching parts: flywheel/ring gear/clutch/release bearing, starter, etc. Overally, the gearboxes gradually improved throughout production from TR2 through TR6. Internally the 3-synchro gearboxes are not quite as strong as the later 4-synchro, mostly in the 1st and reverse gear areas. The late sedan/TR6 gearbox is probably the best, with the most improvements in the end. The difference isn't huge, and might not be a concern unless you plan to race the car and want the strongest possible setup, or if you prefer a full synchro gearbox, or are really concerned about originality.

I don't know how familiar you are with TRs, but the engine/chassis/body/gearbox/differential numbers don't match. They are sometimes close, when all the parts are original. Perhaps a few hundred away from each other. My TR4 is CT17602L chassis (VIN) number. Body is 17768CT. Engine is CT17791E. The original gearbox is way off at CT10091 and the differential doesn't have a serial number I've been able to find. Notice, in particular, how far off the gearbox number is. Even so, I bought the car when it was 13 years old and don't believe the engine or gearbox had ever been pulled for any reason. So I think these are all original to the car.

You might find out more about your specific car by ordering a British Motor Industry Heritage Trust (BMIHT) certificate, based upon the chassis/VIN number. But this will usually - at best - show chassis, body, and engine numbers. If a gearbox was ever factory rebuilt/exchanged, it was typically stamped with an additional prefix, too. BMIHT certificates can be ordered at https://www.heritage-motor-centre.co.uk/archive/certificate/default.htm Along with the various numbers, certificates usually show when the car was built (mine shows Month/Year, but not actual day), exterior color, interior trim, accessories shipped with it, plus when, how and where it was shipped from the factory.