Transmission/Transaxle is unique, and in a few key areas that owners would be hard pressed to duplicate with an aftermarket upgrade. Larger 3/8” tranny cooling lines, and an auxiliary stacked plate tranny cooler in the fender well area with dedicated air cooling duct. Hardened Gears and Gear Carrier Set. Additional nested accumulator springs, other little changes to the tranny, some not listed. The first 4T60 called the 440T4 was the first 4 speed front wheel drive automatic transaxle produced by an American automobile manufacturer. The 4T60 was a greatly redesigned 440T4, now vastly improved!
Tranny Specs:
Manufacture: Turbohydromatic; division of GM
Plant location: Warren, MI
Case material: Cast aluminum
Weight: 192.57 lbs wet
Style: Transverse mount for FWD application
Type: 4T60=
4: 4-speed, T: Transverse Mount, 60: Production Series (engine torque range)
Maximum gross vehicle weight: 6,400 lbs
Maximum gearbox torque: 368 lb-ft
Fluid fill capacity from fully dry: Case/Lines/Coolers: 11 quarts, greater (unique) fill quantity over stock 4T60s
Fluid fill capacity after an overhaul: 8.5L/18 pints/9 quarts
Unique higher count clutch packs
Unique valve body accumulator spring setup
Unique channel plate arrangement
Unique valve body and plates
Gear count: 4 forward with lock-up torque converter, 1 reverse
Forward gear ratios: 1st 2.921, 2nd 1.568, 3rd 1.00, 4th .0705
Reverse gear ratio: 2.38:1
Chain ratio: 35:35
Maximum shift speed 1-2: 6,000 rpms
Maximum shift speed 2-3: 5,500 rpms
Maximum shift speed 3-4: 5,200 rpms but only the early 89s allowed WOT 3-4 shifts
Torque converter type: Fluid drive, with friction pack lock-up clutches; available in 3rd and 4th gear based on load though past 83mph is fully locked at anything other than engine deceleration, or a brake application
Torque converter capacity factor “K”: 177
Torque converter size: 245mm
Torque converter stall speed: 1898 rpms
Differential gear ratio: 3.33:1
Unique Differential construction: hardened gears and gear carrier and steel washers
Control Type-Shift: TV/Throttle Valve cable for up shift and downshift points, and a centrifugal governor regulating line pressure for shifts as well.
Control Type-Pressure: Vacuum Modulator regulated, referenced through a vacuum line just off the back of the upper intake inlet, regulated down by an in-line restrictor to allow the check valve/bleed valve at the modulator to bleed off a boost signal coming from the upper intake.
Unique Cooling System: dual system; larger heat exchanger in the radiator end tank, and a unique auxiliary air to liquid stacked plate cooler located in the passenger front fender cavity. Also unique larger 3/8” cooling lines.
Axle shaft manufacturer; Saginaw division
Axle shaft type: Solid
Axle shaft diameter left: 23.81mm
Axle shaft diameter right: 27.06mm
Universal joint type inner: Tripot joint, 27 sz, 66mm, ball and needle bearing
Universal joint type outer: Rzeppa joint, fixed ball bearing