TR6’S oozing gearbox and clonky exhaust made to behave
In my previous Staff Car Saga, I described how the TR6 was suffering from a flickering speedo needle and a rattling exhaust system. The diagnosis was a sticky speedo cable and a broken exhaust bracket that mounts from the back of the overdrive/gearbox. While I had the gearbox tunnel cover out, I also decided to try and stem the multiple oil leaks from the gearbox and overdrive that have plagued the TR ever since I bought it around 12 years ago. It was obvious EP90 was oozing from pretty much every place it could on the gearbox and overdrive. Reasoning that it’s unlikely every gasket and oil seal would fail simultaneously, I started wondering if the breather was blocked. Removing the filler plug resulted in a gentle whoosh of escaping air, again suggesting a breathing problem.
I looked for a breather to unblock, but found nothing. The ever-helpful chaps on the TR Register forum explained that TR gearboxes have two possible breather locations, either a tiny hole on top of the gearbox cover, or a cylindrical breather on the overdrive. My TR had no breather hole on the top cover and a blanking plug screwed into the overdrive casing where the breather should fit. With no breather at all, it was little wonder the gearbox was pressurised and leaking.
Feeling optimistic that I might have found the cause of the long-term leakage, I purchased a breather and fitted it to the overdrive in place of the blanking plug, then topped with fresh EP90. Since then, the gearbox has barely lost a drop of oil and the drip tray on the garage floor is now redundant. A small victory perhaps, but after so long it felt good to finally nail this problem – and not a single gasket or oil seal needed replacing!
Up the bracket
My next port of call was the exhaust, which had been rattling at tickover due to a broken bracket that connects it to the overdrive mounting and crossmember. I expected I’d have to weld up the old bracket, but found that Rimmer Brothers had new ones on the shelf at a reasonable price. The bracket was ordered and bolted in, then I replaced the exhaust, hanging it carefully to avoid pipes knocking on the chassis rails.
Time to move on to the speedo cable. Speedy Cables lived up to their name and quickly supplied
a replacement. In the past, I’ve discovered to my cost that not all speedo cables are the same and that cheap purchases made online don’t always fit properly. Speedy Cables produce replacements to the original specification and quality – and, sure enough, their new cable fitted the TR6 perfectly.
The final task was to refit the glassfibre gearbox tunnel cover. I’ve found that Triumph cabins can be hot and noisy places, with much of the heat and sound entering the car through the gearbox cover. I ordered a few sheets of self-adhesive under-bonnet insulation and lined the inside of the cover, with heat-reflective foil facing towards the gearbox. The seal between the cover and the floor was still in good condition so I bolted it back in place securely, followed by the carpets and finally the centre console. With the TR back together and standing on its wheels for the first time in several weeks, I ventured out for a test drive. And guess what? The exhaust didn’t rattle, it simply purred. The gearbox seemed quieter with its new insulation, though the speedo needle is still a little twitchy. I got home, parked, then left the car to stand and… next morning, the customary pool of EP90 on the floor under the car was missing. Another bonus is that the unpleasant stench of hot gearbox oil cooking on the exhaust has gone. As for the wavering speedo, I suspect the head unit must need a drop of oil. I promise to get to it soon. Meanwhile, I’m very happy. Three out of four ain’t bad in my book!
Blanking plug was replaced with correct breather.
Exhaust no longer rattles.
New bracket now braces overdrive and crossmember.
New cable fits fine, but the speedometer needle is still a bit fluttery.