The unopened Toyota 1JZ engine has been an absolute dream in the Carnage Trolvo, but sadly our history with the rest of the driveline hasn’t exactly been peachy.

We went through several of the standard Toyota A340 four-speed slushboxes with average results, and while we were able to fix that with an awesome Turbo 400 ’box from the wizards at AllFast Converters in WA, it just moved the weak point straight to the rear diff.

We always knew the diff was a ticking time-bomb, and sure enough Scotty snapped an axle on the grippy surface of Heathcote Park Raceway during a weekend’s racing at King of the Street 6 earlier this year. We did manage to find a spare axle in a wreck at a nearby junkyard and swap it in to continue racing that weekend, but we knew that in the long term an upgraded was needed.

Scotty got into talks with the Volvo specialists at GZ Racing in Sweden, who sorted us out with some beefy upgrades to slot into the standard Volvo diff housing. Included in the kit was a pair of solid 30-spline axles to replace the factory 27-spline toothpicks, along with a Torsen LSD centre and the necessary bearings, and a new set of disc brakes.

Rebuilding and modifying diffs is complex and specialised work, so we called on our mate Luke from Mobile Diff Repairs in Melbourne to massage all the new components into the Volvo’s old housing.

He smashed it out of the park, along with fitting a set of 3.45:1 diff gears to replace the original 3.73s. The reason for this is because the Trolvo was struggling for decent top end over the quarter-mile. Since our Turbo 400 has a transbrake, we’ll still have no issues leaving the line at full chat.

While Luke was sorting the diff for us, Scotty started fitting all-new bushes to the original control arms, after giving them a quick clean-up in our Hare & Forbes bead blaster.

Unfortunately, due to the Victoria-wide lockdown currently in place, you’ll have to wait for part two, where we’ll slot the diff back into our Volvo 240. Progress on Scotty’s VE Valiant ute has also stalled until we can safely return to the workshop.