I'm doing a transmission service here at 30K (at 26K right now) and will be installing a PPE pan, along with a new filter etc. Wondering if there is anything else I can be doing while I'm in here.
Sometime in November of '24, Amsoil released their new Signature Series ULV. Does anyone have any thoughts on this, or has anyone tried it in their 10R? Seems there are some mixed opinions on whether it's 1) worth the steep cost and 2) contributing to higher overall transmission temperatures and is potentially damaging. This leads me to believe I should just stick to OE fluid and be diligent about fluid changes and service every 30K.
Sources for reviews:
Key MERCON ULV Specs vs. Amsoil Signature Series ULV
Sometime in November of '24, Amsoil released their new Signature Series ULV. Does anyone have any thoughts on this, or has anyone tried it in their 10R? Seems there are some mixed opinions on whether it's 1) worth the steep cost and 2) contributing to higher overall transmission temperatures and is potentially damaging. This leads me to believe I should just stick to OE fluid and be diligent about fluid changes and service every 30K.
Sources for reviews:
| Link | Positive? | Date | Key User Reports |
|---|---|---|---|
| Reddit r/f150: 10 Speed Transmission - Amsoil Signature Series ATF? |  | Jan 21, 2025 | Users report "rave reviews" for smoother shifts/towing/cold performance in 2020+ F-150 10R80s. One: "I’ve used Amsoil in all my cars... great improvement in shifting." Another: "If rated for ULV, you're good—updated fluid fixes old issues." (Mixed with Valvoline ULV comparisons.) |
| F150Gen14 Forum: Amsoil now has ULV ATF (Page 2) |  | Nov 2024–Jan 2025 | Early test in 2020 F-150: Drain/fill showed "immediate increase in trans temp (189–191°F in stop/go traffic)" and "more clutch slip." User reverted to Mercon ULV after 1 week: "Temps/shifting back to normal." Costly experiment, but highlights potential viscosity quirks. Others: "Wait a year for more data." |
| F150Forum: Amsoil ATF for 10R80 Transmission? (Page 2) | | Jan 2025 (ongoing) | 10R80 owners: "Smoothed odd shifts... very happy." One with 2023 F-150 Tremor (like yours): "Used in 6R80/10R80—smoother under load, no issues at 20K miles." Notes easier direct buy vs. dealer markup. |
| BobIsTheOilGuy: 10R80 ATF | | Updated Jan 2025 | F-150 user after ULV swap: "Shifts feel crisper hot... 10°F cooler towing 8K lbs." Compares to Valvoline ULV: "Amsoil edges on longevity, but Motorcraft fine for most." One negative: "Heavier shifts initially—adapted after 200 miles." |
| Ranger5G Forum: Now they (Amsoil) came out with their ULV transmission fluid | | Mar 18, 2025 | 2020+ Ranger/F-150 hybrid thread: "4500 miles post-swap (PPE pan + ULV)—smoother, runs 5–8°F cooler off-road. Worth $17/qt for severe use." Skeptics: "Overpriced vs. Motorcraft $5/qt—stick to OEM." |
Key MERCON ULV Specs vs. Amsoil Signature Series ULV
| Property | Ford ULV Limit | Amsoil ULV Value | In Spec? | Notes |
|---|---|---|---|---|
| KV @ 100°C (cSt) | 4.2 min / 4.8 max | 4.5 |  Yes | Dead center—critical for 10R80 shift calibration. Old ATL was 6.3 (way over). |
| KV @ 40°C (cSt) | 17.5 min / 21.5 max | 19.2 | Yes | Ensures pump efficiency and cold flow. |
| Viscosity Index | 145 min | 160 | Yes | Higher = better temp stability (Amsoil edges Ford's typical 150–155). |
| Brookfield @ -40°C (cP) | 10,000 max | 9,500 | Yes | Flows better in extreme cold. |
| Flash Point (°C) | 180 min | 210 | Yes | Higher boil point resists breakdown during towing. |
| Pour Point (°C) | -48 max | -51 | Yes | Slightly better low-temp performance. |
