Peugeot PSA BE3

PSA's five-speed manual transaxle, and — because Iran Khodro has built it under licence since the turn of the century — the gearbox in almost everything Iran Khodro sells with three pedals: the Samand, the Soren, the Dena and the Peugeot Pars, alongside the Iranian-built Peugeot 405 it arrived with. In Europe it is the unit that replaced the BE1 in the 405.

It is a transaxle rather than a gearbox, and that one fact answers most of what is asked about it. The gear train, the final drive and the differential share a single aluminium case and a single oil, so the differential is inside the gearbox. Two consequences a diagnosis turns on: a noise that rises with road speed in every gear is coming from the final drive, where one that follows engine speed and changes with the gear selected is coming from the gear train — and both are this unit; and running it low on oil damages the crownwheel and the gears together, because there is only one supply.

Iran Khodro is designing a replacement for it, and the stated reason is the useful part. The EF-series engines it now sits behind ask more of it than the 405's XU7 did, and the replacement is described as one that will handle higher torque and be more efficient than the BE3/5. Read a BE3 behind a turbocharged EF7 as a unit working close to its rating rather than one with headroom.

What a workshop meets, in the order the factory overhaul procedure meets it:

• End-float, and the noise it makes. The shafts and the synchro hubs are shimmed and their clearances set with a feeler gauge on rebuild. Left wide, the gear train takes a shock every time drive is applied or released, so the complaint is a knock or a rattle on pulling away and on lifting off rather than a fault in any one gear. It is an assembly fault, so it arrives after a rebuild as readily as after mileage.
• Hard selection and jumping out of gear, which the same procedure treats as one family of problem — worn engagement teeth and sliding sleeves, not a synchro on its own.
• The differential oil seals, inspected at every overhaul because they are where the shared oil leaves. A BE3 that is simply low on oil presents exactly like one that is worn out, and the cheap check comes first.
• The oil itself. It is not a sealed unit; the interval commonly published for it in Iran is around 60,000 km.

For an owner: this gearbox is ordinary rather than fragile, and most of what is said against it is really said about the mileage it has done and the oil it has not had. The one thing to respect is its rating. It was drawn for the engines of a 1980s saloon, and a 1.7 turbo is asking more of it than its designer had in front of him.