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Project Tomcat, Failure to Proceed

Well, that didn’t take long.

I knew I was on borrowed time with the gearbox but didn’t expect it would come around this quickly.

So, I had the new tyres fitted yesterday (Yoko AD08r in the correct Turbo size), fiddled with the old brake light switch (since the replacement is AWOL) to stop the brake lights from being on all the time, and then went out to bed the new brakes in.

The car was running great, it ran smoothly and was responsive. The brakes have good feel, with no shudder and the gearbox was shifting great.

A few hard stops and a KM or two later I pulled over to check the wheel nut torque (not going to take the risk of not checking them after a brake job again, after the wheels nearly coming off on the Corolla). Of course, the wheels were fine, so I pull back onto the road, gave it a bit of throttle, the turbo spins up, boost comes in and then suddenly

It just free revs. It felt like it popped out of gear, so I clutch in, into neutral, into second, let the clutch out, and nothing, just revs. Oh no. I roll to a stop at the side of the road and try a few more gears, nothing, I can let the clutch out with it in gear and nothing happens, doesn’t even stall. I can push the car forward when it’s in reverse, which is not good.

I fire off a quick text to let my Wife know I might be a while and call AA to arrange a tow. “Yes, I am about 1.6KM away from home” I confirm with the rep on the phone…

At least it looks good, sitting there, waiting.

Whilst I waited I took a quick walk back to where I stopped to check the wheel torque

A quick sniff test confirmed that was a nice trail of my fresh, rather expensive, Honda MTF gear oil. There was also a small amount under the car where it sat.

After a fairly short wait, a friendly chap with a truck arrived winched the old girl aboard and dropped me home again. The Tomcat repaid his help by leaving a large amount of gear oil on the truck bed, and on the road where the car was loaded and unloaded.

So what went wrong then?

I jacked the front of the car up, confirmed it had no drive to the wheels and slid under to find out why.

That’ll do it. The shiny bit the arrow is pointing to should be inside the gearbox and shouldn’t be visible. It also explains why the gearbox weed everywhere as the seal was wide open without the shaft to seal it.

I did some careful levering with a prybar and popped it back into place.

I’d be very surprised if this is a new issue… I suspect I’m not the first one to lever that back into the gearbox.

Whilst under there I had a good look around. Noticed a couple of minor coolant leaks I will need to attend to, but also noticed this rear engine mount completely missing its nut.

I found a new pre-loved nyloc nut that fit, and wound that on nice and tight. Who knows, maybe that will fix some of the movement in the engine.

The driveshaft has quite a lot of radial (up and down) play when inserted back into the gearbox, which confirms my suspicions, both about the condition of the box, and why it popped out; the gearbox bearings are stuffed.

These gearboxes do not tolerate being neglected, and being over a litre of oil down when I got it, I suspect it’s not had a good time.

When Rover had these boxes built, they chose to use hi-tech ball bearings with plastic to retain the balls. This probably seemed like a good idea at the time, and they worked well for years, as long as the plastic didn’t get old and the gear oil could keep them cool

Above is an example of the bearings used in the PG1 gearbox; uprated steel cage bearing on the left and stock plastic cage on the top right.

Unfortunately, the bearings Rover used seem to wear badly no matter what (they tend to get pitting in the races and go a bit grindy), but when coupled with low oil and high temps, the plastic can fail, causing the bearings to no longer be sufficiently retained, as per this extreme example where the plastic has broken and the balls have all converged on the lowest point. This sort of damage is what can also break the flange off the diff center.

So I suspect mine has either started to break down the plastic, or the races have worn to the point there is excessive play. The popping out drive shaft is the usual giveaway of bearing failure.

With the driveshaft back in place, I have drive to the wheels again, so once I refill the gearbox with the cheapest oil I can get, the car will be mobile enough to get out of the garage and into the drive, where it will sit in shame waiting for me to rebuild the gearbox.

I will be stripping the gearbox, replacing all the bearings, and oil seals. Uprated metal caged bearings will be used everywhere they are available. Whilst I’m there I will also be doing the clutch. I’m hoping to keep the Type A torsen diff, but I will need to check it’s in good condition once the gearbox is split; if not, I will need to increase the budget and add a Quaife to the list. After that, the gearbox should be damn near bulletproof.

I was really hoping to get more than a couple of KM (literally, I’ve done sub-10KM since I got it) out of the car before it seriously broke, but that’s the British car game I play. Every day is a gamble.

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