I've seen one 3.15 that I can verify 100%.
In '83 (Built sometime '82) 764TD exactly like you'd think it would be.
Damascus self-serve junkyard, 100+ volvo RWDs on the back few rows for several years running, ~Y2K before digital cameras were common?
10+ 240Turbos at a given time, walked past what was ?~$1,000,000? in 240Turbo-specific parts in today's dollars over time, inflation-adjusted before they recently became pretty worthless again/no cars left to put them on?
Not totally uncommon, TD or V6 '83 760s I've seen both with BW55, diesels were somewhat weird that way; they didn't always get the flagship trans option first on flagship/limited production models.
That ZF trans probably wasn't ready to go as soon as the Aisin was?
Remember, they used the ZF auto in N/A gas 700s starting in 85 model-year (built in 1984) with fuel-saving/still-emissions-passing @ 55mph cruise (tho USA emissions testing procedures (not steady state fed. mandate 55-stay-alive cruise anymore) changed 83+ as did bumper regulations) stronger torque converter clutch than the Aisins offered with MUCH stronger OD/1:1 direct drive/converter locked up out of OD possible for towing for the N/A 4-banger common redblock models?
Kinda same as the 164 in that way; D-jet till the bitter end, no K-jet; low production volume model, why make changes if they don't (yet) have a path to carry on/over as interchange with the newer/higher production volume models?
Whereas the 240Turbo got the 4-speed auto-tragic that was going to be an across-the-board change for all 4cylinders a year early ('82), but 260 didn't IIRC/they were about to kill the 260 model off.
Volvo makes sense that way; use whatever you have laying around, limited production models have soldier on unchanged if they're about to be killed off often times & the parts have no future across the board high production # use?
Took them a minute to have the B28/B280 bellhousing ready to go and decide to use the AW-71 on the V6 cars too...that's such a weird obscure partnership/abortion with Eagle/Dodge/Renault/Peugeot how that played out.
TLDR; uncovered the sticker/verified at least one 3.15 existed and counted teeth & pulled it for someone with a V8.
"Some of us actually do these things."
Worked ok when the ford SBF was all the rage before the LS motors were littering every JY/only used in a few years in 98+ corvette/camaros of common/cheap production cars with a blown 347 stroker SBF & 2.95-.80 ratio spread before 6-speeds were common IIRC?
T5s are garbage, had to spend big $ to get a TKO or live with a 4-speed or auto-tragic in those days often or buy an expensive Doug Nash OD or gearvendors OD.
Dark/primitive days.