Allison TES 295 Transmission Fluid: What It Is and When Your Transmission Needs It
The short answer
TES 295 is Allison Transmission's specification for fully synthetic automatic transmission fluid. A fluid only meets it if Allison has tested and approved it. Allison approves fluids by brand and product name, not by type, so a fluid labeled "synthetic" or "compatible" is not automatically TES 295. Allison's own fluid, TranSynd, is the best-known TES 295 product, and several other brands also hold approvals. You need a TES 295 fluid if you want to run Allison's extended drain intervals in a transmission that permits them. If your manual allows either TES 295 or the conventional-based TES 389 fluid, both work, but the service schedule depends on which one is in the transmission.
Two things can change this answer: the exact transmission model, and the vehicle manufacturer's own fluid requirement. Both are covered below.
Which transmissions the specification applies to
TES 295 is mainly tied to Allison's on-highway automatic transmissions, such as the 1000/2000 and 3000/4000 families used in medium- and heavy-duty trucks, buses, motorhomes and vocational vehicles. Allison's off-highway transmissions, and some newer or specialized models, can have different fluid requirements. Do not assume TES 295 applies to every unit with an Allison badge.
For pickups and other light-duty vehicles with an Allison transmission installed at the factory, follow the vehicle manufacturer's owner's manual first. That manual sets the requirement for that model year and powertrain, and it may name a specification other than an Allison TES number. The requirement can also differ between model years of the same truck line. This article does not have evidence covering specific vehicle years, markets or trims, so confirm against the manual for your exact vehicle.
TES 295 compared with TES 389
Specification | Base fluid | What it supports; TES 295 | Fully synthetic | Allison's extended drain intervals, where the transmission and its service schedule allow them; TES 389 | Conventional (mineral-based) | Allison's standard drain intervals, which are shorter than the TES 295 intervals
In practice, the choice comes down to cost per fill versus how often you service the transmission. A synthetic TES 295 fluid usually costs more per fill but can mean fewer changes. Whether that saves money depends on your duty cycle, the transmission model and the filters fitted. No pricing or interval figures were supplied for this article, so check current prices and the schedule for your unit.
How to confirm a fluid is genuinely approved
Look for the Allison TES 295 approval number printed on the container. Approved products carry an approval number. Wording like "meets the requirements of" or "suitable for" is not the same as an approval. Check the exact product name against Allison's current approved fluid list. Approvals belong to a specific product and can change, so an older list or a similar-sounding product from the same brand is not enough. Match the specification to your transmission's operator or service manual, including any vehicle-manufacturer requirement that takes precedence.
Drain intervals and switching fluids
Allison publishes drain and filter-change intervals in its service documentation. They vary with the transmission family, the vehicle's vocation (general or severe duty), the filter type, and whether the transmission's oil-life monitoring (prognostics) is enabled. Specific interval figures were not supplied for this article and are not given here. Use the current Allison documentation for your unit.
Mixing affects those intervals. If TES 295 fluid has been mixed with a non-TES 295 fluid, or the transmission is being converted from a conventional fluid, Allison's extended intervals may not apply until the changeover procedure in its service documentation has been completed. Until the fluid's history is known, service on the shorter schedule. This matters most for used vehicles with unknown service records.
What this article could not confirm
No source documents were supplied with this brief. The following points are therefore not covered and should be checked directly: • Allison's current list of approved TES 295 fluids; • Exact drain and filter intervals; • Fluid capacities; • Prices; • Factory fill requirements for specific vehicle model years, markets and trims; Allison's service documentation and your vehicle's owner's manual are the authoritative references.