Product DetailsNew and unpainted ZF 68A marine transmission. Part number 3312001204. The ZF 68A supersedes and replaces the ZF 63A and Hurth HSW630A (part number 3312001020). It has internal improvements to reduce gear noise and is the same externally for direct interchangeability.
- Gear Ratio: 2.522:1 (A), 2.536:1 (B)
- Mechanical Shift (contact for electric shift availability)
- 8 Degree Down Angle
- Oil Filter Included
- For standard-rotation engines only (same as automotive rotation)
- Can be shifted either direction for forward (fully-reversing)
- Output coupler has 4 bolt holes and 4-1/4″ bolt center-to-center diameter
Owner’s manual included. Sold by a ZF dealer with full warranty. Does not come with any accessories.
To improve transmission longevity and preserve the warranty, please follow these guidelines when installing and running your new transmission:
For transmissions that use an oil cooler, it is important to have it serviced or buy a new one (and flush the oil lines). If there had ever been water, metal particles, or other debris in the old transmission oil, or the old transmission failed or was slipping, reusing an old oil cooler can cause debris to enter the new transmission through the cooler circuit, which can void the warranty and lead to premature failure. The ZF complete cooler kit for the 63, 68, 63A, and 68A model transmissions is part number 3312107001, available here.
If you need a new oil cooler, you can view a list of coolers here. The oil cooler used by the transmission will vary depending on the engine make and model, so yours may not be listed. Contact for help if needed.
Also called a drive plate, this bolts to the flywheel and engages the transmission input splines. It dampens the engine torsional firing impulses to protect the transmission. An old, damaged, or worn out damper plate may not dampen the torsionals as well, leading to premature wear and tear, or in the worst case a complete failure. If you need a new damper, you can view a list of dampers here.
If you’re changing from a Volvo MS-series transmission to a ZF, you’ll also need to switch from the original spring type to a Centa bushing type damper.
Oil Changes & Fluid Types
Check your transmission oil fluid level regularly and change it following the owner’s manual guidelines. Never go more than a year between oil changes. If you aren’t sure what oil type to use, here are recommendations:
- For ZF 12, 15, 25, 30, 45, 63, 68, 80, and 85 series, and Velvet Drive 71C, 72C, 73C, and 5000 series, use an ATF fluid which meets Detroit Diesel Allison C-4 specifications (e.g.: Dexron IIE, Dexron III).
- For ZF 220 and larger series, use a marine 30W transmission oil (no/low detergent, not multi-grade). In very hot climates 40W is okay.
For transmissions with an oil filter, replace it as needed following the owner’s manual guidelines. Find replacement oil filters here.
The adapter housing is what connects the transmission to the engine bellhousing. You can usually reuse your existing one as long as it is not damaged. If you need a new one, see here for a list of common adapter housings.