4l60 Hydramatic RPO MD8 Tranny Compatibility

[Build to the Bone]

I been doin my homework but am still not sure which GM transmissions will work in place of the 4l60 RPO MD8 because I don't want to have to do a bunch of modifications, the less the better. My truck is a 1991 chevy k1500 5.7L 4x4. I was also wondering the correct way to measure it also, like from which face or point to wherever else?

 

[Wes Harden]

700r4 will fit. Best choice is 1991 up K case.

Th350 will be 1.75" shorter than current trans. only 3 speeds, no overdrive. You will have to move crossmember and adjust driveshaft lenghts

 

[imiceman44]

700r4 will fit. Best choice is 1991 up K case.

Th350 will be 1.75" shorter than current trans. only 3 speeds, no overdrive. You will have to move crossmember and adjust driveshaft lenghts

700r4 is the 4l60.
I know that most major improvements were made by 89, so 89-95 should work

 

[Wes Harden]

I don't call them a 4l60 until the "E" is added.

 

[imiceman44]

I don't call them a 4l60 until the "E" is added.

I know, I don't either but gm did so I was clarifying to OP

 

[Blue85]

The electronic versions (that require the modifications you're trying to avoid) have a large round electrical connector on the side:



The hydraulic shifting versions have the 4-pin square connector and the hole for the T/V cable to bolt into:



Here's the history I posted before. It's just gleaned information from sources on the internet, so there may be some errors. It looks like the oldest you'd want to look at is around 1987 when ECM lockup control started. The best would be around '89 to sometime around '93.

1982: TH700R-4 is introduced, using 7-vane pump and 7-element forward roller clutch assembly
later '82: upgrade of forward roller clutch to a sprag
1984-1986.5: input shaft goes from 27-spline to 30
1984:

• New input housing with ball capsule
• larger diameter turbine shaft
• new rear internal ring gear
• new 10-vane "732" pump

1985:

• planetary gears upgraded to "batwing washer" style
• added inner pump slide spring
• new reaction carrier with oil dam

1986:

• Reverse input housing thickened in band apply area
• new low roller clutch (longer rollers)
• new accumulator pistons and seals

1987:

• Electronic speed sensor
• Aux valve body softens engagement
• new overrun clutch hub
• 28-element forward sprag
• new spacer plate
• 2-4 servo pin seal rings and grooves eliminated
• Ball capsule added in reverse passage (case)
• Type-15 wiring harness and temperature switch
• upgraded sun shell with 5-disc stepped-plate 3-4 clutch (this may also be when the thrust washer against it was replaced by torrington bearing).
• TCC lockup valve now plugged in the valve body (to coincide with ECM control)
• Revised filter and seal

1988:

• New 1-2 shift valve
• Load release springs added to 3-4 clutch pack
• Case change L/R hub
• Type-18 wiring harness removes 4-3 pulse switch
• Improved governor gear

1989:

• Name changes to 4L60
• Valvebody no longer has a bore for TCC lockup valve
• Short lip seals introduced for forward, reverse and 3-4 clutches

1991:

• High energy 3-4 friction plates
• New rubber seal, input housing to output shaft

1993:

• 4L60-E phased in
• 1-2 and 3-4 accumulator changes
• New reverse input housing
• Thicker steels in 3-4 clutch

1995: PWM lockup
1996: separate bellhousing, updated input clutch housing and 13-vane pump
2001: All new sun shell with 6-disc 3-4 clutch

 

[Build to the Bone]

Awesome guy's that information helps out alot, I know what I'm after now thanks

 

[Build to the Bone]

700r4 will fit. Best choice is 1991 up K case.

Th350 will be 1.75" shorter than current trans. only 3 speeds, no overdrive. You will have to move crossmember and adjust driveshaft lenghts

Mmmkay nd what about the turbo 400, similar issues.?

 

[Wes Harden]

Th400 is 1 longer in the case, also the output shaft is 32 spline. Your current tcase is 27 spline input, that can be changed with an input gear swap. Drive shafts might work ok.

 

[tarussell]

Th400 is 1 longer in the case, also the output shaft is 32 spline. Your current tcase is 27 spline input, that can be changed with an input gear swap. Drive shafts might work ok.

Also will require a different adapter - TH400’s 6-bolt v/s 700R4’s 4-bolt rear case mount pattern.