TR2/3/3A TR3 Trans tunnel holes

Hello, listers, reading Winston' musings about gear oil changes, and looking at a trans tunnel on eBay, spurred me to look at my "Practical hints for the maintenance of the TR3".

Page 16 shows a photo of a rubber plug on the passenger side of the tunnel, exposing a dipstick for the gearbox oil level. The eBay tunnel shows the same hole. The search of my car shows a small rubber plug on the drivers side of the tunnel, about an inch off the floorboard, revealing a small 4-sided metal plug, (not lined up with the rubber plug), which is ,I'm guessing, the fill hole.

My question here is, is this change a normal occurence, and I wonder what other changes are not "by to the book". Is it any easier to remove the tunnel itself to add oil, as opposed to trying to snake it through the offset hole? FWIW, my car is commision #58370, 1960.

For those listers kind enough to respond to my initial posting of reviving my long-slumbering TR3, I've added pix #165 and #166 to the gallery... Thanks all! Kevin

Hi Kevin,

My car is a TR4, but there's not alot of difference in this area, except that the later car doesn't have a dipstick for the gearbox.

I've always filled the gearbox from below. There are inexpensive pumps available at most auto parts stores for this purpose.

On the TR4, you just fill until it's level with the hole and runs out. Perhaps the same filling and level procedure will work with your TR3.

I put my car up on jackstands so that it's safe and secure, and reasonably level to most accurately get the oil to the right level in the gearbox. Then I slide under on a creeper to do the drain and refill. In my opinion, it's a whole lot more work and hassle to remove the gearbox cover, carpet, etc. Of course, on your car you don't have to contend with the center dash support that I do. (By the way, one way to get around that on the TR4 is to modify the gearbox cover into a two-piece, sectioning it right at the dash support, so that only back half needs to be removed to get reasonable access.)

You'll find 7/16" square plugs on the legthand side and on the bottom of the gearbox. Bottom to drain, side to fill, of course.

Use a GL4 type 90W gear oil, *not* GL5 (contains sulfites that will attack brass parts in these old gearboxes). If you have trouble finding 90W, a multi-viscosity GL4 is okay, too, in say 75W90 or similar weight. An alternative is Castrol or Valvoline 20W50 Racing (non-detergent) motor oil. Synthetic oils are *not* recommended for these gearboxes, might lead to popping out of gear.

While I'm under there, I like to take care of a number of things. It's a good time to replace the oil in the rear end, too. 90W GL4 is used there too, I believe. Check your manual.

You might also want to drag along a grease gun and put a squirt or two into the zerks on either end of the clutch release bearing shaft (either side of the bell housing), the one in each of the front and back drive shaft u-joints (most have zerks, but some replacement u-joints do not), on the handbrake cable (a single a zerk midway along the cable), and the handbrake compensator (two zerks hiding on top of the rear axle, righthand side) and one at each outer rear axle seal (on TR4s, I'm not sure if they are also on TR3s). There are also zerks in the front suspension and steering, but those are easily accessed from the side of the car. I think that's everything, but check your manuals to be sure.

If you wish, some spray-on grease can be used to lube the various clevis pin connectors at the ends of the three handbrake cables, and the mechanism at the base of the handbrake.

While under the car is a great time to check the clutch slave cylinder and brake lines for any signs of leakage. Another thing I'd check is tightness of the 4 bolts at the front and 4 bolts at the rear of the drive shaft (But, this is just personal paranoia after finding 6 of the 8 bolts on my car could be unscrewed by hand, no wrench required! I shudder to think what might have happened if they'd backed off just a few more and the drive shaft had come loose!)

I hope this helps!

Alan

That hole you found is someone's attempt to make adding gearlube a bit easier - too bad they didn't get it better aligned to the plug. The dipstick was dropped as a part of the changes implemented at TS50001 -- it is a nice feature on the older cars.

No way I could imagine pulling the gearbox tunnel is less bother than simply getting a tube into the filler hole from above, below or thru that hole you found.

One other difference in this area from the TR4 Alan mentions is that TR3As have sheet metal tunnels, the TR4s had a fibreboard tunnel unless a plastic or fibreglass replacement has ben fitted.

I like to fill from above though this works best with the car raised and Alan's suggestion to use the opportunity to lube & inspect all along the underside is a good idea.

If you're going to be filthy you might as well be thorough.

Oh to be filthy again. I can hardly wait till the day the various fluid's once again become viscous,broken from the winter's grip and into mine.
A King's ransom would I give for a heated garage,had I the ransom to give.