Gearbox Breather Hole

[Perrymip]

Roger Williams mentions a 1/16" breather hole "at the front of the gear change extension," that might inadvertently be left blocked, causing serious oil leaks. Does anyone have alternative (better) instructions for locating this hole? I can't find it.

 

[TR3driver]

Far RH edge of this photo, near the upper bolt hole.

 

[vettedog72]

I guess you have to take the transmission cover off to check the vent?

 

[Geo Hahn]

Looking at my spare gearbox (from a 64 TR4) I do not see the hole shown in the above picture. A cursory examination did not reveal any other obvious vent.

 

[TR3driver]

I guess you have to take the transmission cover off to check the vent?

It could be worse. To check it on a Stag, you start by removing the radiator ...

 

[Perrymip]

The photograph was very useful. Now I know why I've not been able to find that hole. I also know why all those gallons of oil disappeared over the last decades.

 

[Don Elliott]

Perry - The cover you show is not from a 1958 TR3A or else your TR must have been built very late in 1958. My 1958 TR3A (TS 27489 LO) was built in February, 1958 and it has the hole for the dip-stick as shown in my photo. The photo you show has no top dip-stick fill hole, so I assume that you have to fill the gearbox via a hole over on the LHS. I don't have the fill hole or plug down on the LHS of the gearbox housing. Note that mine does not have that vent hole it the top cover either. But with the dip-stick in the hole on the right, I have to assume that any pressure build-up might have vented itself via the dip-stick hole even though it's a loose/snug fit with well oiled felt about 1/16" thick wrapped and glued to the outside diameter (about 3/4" or 1") of the dip-stick.

Also the connectors for your overdrive cut-out switches have push-on spade connectors and S-T didn't start to use these till after TS 60000 about 1960. Mine show the screw-on connections.

 

[TR3driver]

Good point, Don. I believe the dipstick was deleted at TS50001, same time the bellhousing changed to accomodate the later starter. That change point was in early 1959.

There have been at least a few people that tried to swap a later top cover onto an earlier box, and had no way at all to fill it (except turn it upside down and use the drain :laugh: ).

The vinyl OD harness & Lucar connectors also suggest that Perry has a later box.

I'm sure I've got at least one example of a later 3A top cover up in the attic somewhere. I'll try to dig it out and see where it's vent is.

 

[Perrymip]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]not from a 1958 TR3A[/QUOTE]

Yes, sometime in the mid-60's I decided that first gear synchromesh would be a nifty idea. As I remember this came from TR4.

I believe it was about the same time and with same degree of adolescent enthusiasm that I undertook to "rebuild" the carburetors. It was about a month ago and because of this forum that I realized I had put the choke linkage together wrong.

All those years of making up solutions on ones own, not trusting anyone over thirty, therefore not asking nor getting good advice. It's astounding the car survived my adolescence. It's astounding that any of the TRs survived anyone else's adolescence.

 

[sail]

My 4A does not have one. I figure if it's not leakin it must be empty.

 

[Don Elliott]

Perry - I bought my 1958 TR3A brand new when I was an adolescent - only 20 years old. I paid cash with the money I saved between high school and age 20. It has survived all these 51 years. So have I. I'm still an adolescent.

 

[Perrymip]

So maybe we can guess from this that the gearbox breather hole became a reality at about TS50001 (after the dipstick disappeared) and lasted only through the TS series (TS82xxx?). So TR3B, 4, and on had no such amenity. And, presumably, all leaked like sieves.

 

[prb51]

My TR3 early box with dipstick leaked like a sieve too. Thru both the rear main seal (replaced and rereplaced...no joy) and thru the upper stickshift rod seals...really rustproofed anything south of the tranny.
"I love the smell of gear lube in the morning"

 

[MDCanaday]

I think Perry is onto something,when they deleted the dip stick I believe they forgot to vent it at all.This led to one more oil leak on cars that really didnt need any help with leaking oil.Brilliant!!!(pass the dark ale of choice)
MD(mad dog)

 

[bgbassplyr]

Anyone ever added a dip stick by drilling through the unused boss where the original DS went?

Jim

 

[Don Elliott]

I know several who have done that.