Velvet Drive 72C Series

The 72C is the cast-iron 72 series Velvet Drive, the bigger sibling of the 71C, in part numbers starting 1018. Like the 71C, it's an in-line transmission, built as a 1:1 direct drive and in reduction ratios. Our rebuilt listings run from the 72C 1:1 (REB 1018-002) up to the 2.91:1 (REB1018-012). Because of their size, 72 series units have to go out by truck.

What's different from the 71C

The 71 series (1017) and 72 series (1018) clutch packs differ in one key way: the 71 uses two snap rings, and the 72 uses three. The 72's third snap ring goes on the bottom of the clutch pack, underneath the bottom pressure plate, and it's what gives you your clutch clearance. Both have a groove on top of the pressure plate that isn't for anything, so don't put a snap ring in it.

Clutch clearance is where the two families really part ways. On a 71C, bronze and paper clutches share the same clearance. On a 72C, bronze runs 0.035 to 0.055 in and paper runs 0.021 to 0.046, so the two builds aren't the same spec, even though both are still in the factory manual. The clearance-setting snap ring itself comes in four thicknesses on a 72C: green (.050-.054 in, one or two used), orange (.074-.078 in), white (.096-.100 in) and purple (.062-.066 in).

Every 72C also runs its reverse gear about 10% deeper than forward. A 1:1 reverses at 1.10:1, a 1.52 at 1.68, a 1.88 at 2.07, a 1.91 at 2.10, a 2.10 at 2.31, a 2.57 at 2.83, and a 2.91 at 3.20. A 71C's forward and reverse ratios are equal, so that gap is a clean way to tell the two families apart.

The 72 shares its case style with the 71 series and the 1004/1005 cast-iron V-drives, including the cooling line out port and the pressure port on the ridge toward the front. The 2.10:1 is the exception on the return port: they plugged the usual spot and put the return on top of the reduction planetary. Chris calls the 2.10:1 the worst transmission Velvet Drive did in the 71 and 72 series in-line configuration, because it generates a lot of heat. Same shop rule as the 71C, by the way: no copper washers under the pump bolts.

Velvet Drive 1018-106 1.91:1

Specs and ratings

Pumps and rotation

On the newer Velvet Drive pumps with a guard around the seal, you have to take the pump off the transmission and drive the seal out toward the transmission side. On the early pumps and the aftermarket version, you can just pull the seal out. You can change rotation on most cast-iron transmissions by loosening and removing the pump bolts, tapping the pump loose, rotating it 180 degrees and reinserting the bolts. That only changes the pump rotation. It won't change which lever position is forward.

Velvet Drive 71C 72C clutch packs 1017-004

Don't see the part you need listed? Call Chris at (804) 333-3677, Monday to Friday, 9 to 3 Eastern, and ask.

Related problem articles

• Changing pump rotation
• Snap rings installed wrong
• Front seals blowing out
• Don't paint the coupling