The Peterbilt 310 front and rear turn signal bulbs utilize 2057 and 198 sizes, with the replacement chart detailing bulb specifications across vehicle production years. The data covers 1986 to 1987 model years in the replacement chart.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Peterbilt 310 front and rear turn signal positions draw from two distinct bulb types across the 1986-1987 model years: the 2057 and the 198.
The 2057 is a dual-filament bulb operating at 12V with a high/low wattage split of 26.9W and 8W, mounted on a BAY15d bayonet base, and classified under ANSI standards for the US and Canadian markets.
The 198 is a miniature wedge bulb of the T5 form factor, rated at 12V and 2W, also carrying ANSI classification for US and Canadian markets.
The 2057 is noted as a brighter variant of the 1157, sharing the same BAY15d base type, which means the two bulbs are physically interchangeable in terms of socket fit, though their output characteristics differ.
On the Peterbilt 310, the 1987 front turn signal position accepts either the 2057 or the 198, with the 198 applying specifically to vehicles equipped with halogen capsule headlamps.
The headlamp configuration on the 1986 Peterbilt 310 directly determines the front turn signal bulb size, as the 2057 is specified for vehicles with four rectangular headlamps while the 198 applies to other configurations.
The rear turn signal on the 1987 model follows a similar configuration-dependent split, with the 2057 specified for vehicles carrying four round headlamps and the 198 designated otherwise.
The 1986 rear turn signal position uses only the 2057, without any noted configuration-based variation.
Because the 198 operates at 2W and the 2057 operates at up to 26.9W, substituting one for the other would produce a significant difference in output intensity, making the two bulbs functionally non-interchangeable despite both being listed for the same vehicle.