here is the info from the ATSG TSI
ROLLER CLUTCH FAILURE
COMPLAINT: NO. I: Some 1991-1995 model vehicles equipped with the THM 4T60-E transaxle may
exhibit a no movement condition, with the selector lever in the D4 or 03 ranges, but will
move when the selector lever is placed into D2 or Lo range.
NO.2: When the engine RPM is increased with the selector lever in the Park or Neutral
position, you may hear a noise that sounds like "Marbles in a Can'', but still moves and shifts
CORRECTION: The cause for both complaints listed above is a 1-2 roller clutch failure.
Replace the l-2 Roller Clutch Assembly and any related parts that may be damaged or I
broken (See Figure 1). Before installing into the transaxle, always replace the OEM 1-2 roller
clutch springs with Sonnax part number K84956~SP, which contains 16 stronger according
springs and is available from your aftermarket parts supplier (See Figure l).
This is recommended as part of every rebuild to increase transaxle durability.
DO NOT EXCEED 3000 RPM WITH THE SELECTOR LEVER IN REVERSE AND
THE WHEELS OFF THE GROUND. IF YOU DO THIS WITH OEM 1-2 ROLLER
CLUTCH SPRINGS, YOU CAN FAIL THE 1-2 ROLLER CLUTCH BEFORE IT EVER
LEAVES THE SHOP!