Hey Everyone,
Starting a similar thread to the 6L80 post but dedicated to the 4L60E as countless GM cars, trucks and SUVs were fitted w/them from 1993-2013/14, including those owned by many of us (I have a 2003 Tahoe Z71). Posted below is my teardown and inspection video that covers everything you need to check for as well as a link to my 4L60E playlist that covers valve body disassembly and reassembly, full rebuild, and related topical videos. I included a complete parts and machining procedures list as well so folks have a comprehensive view of everything that needs to go into these transmissions for a proper overhaul. Lastly, I have included some tech resources and information for those that want to rebuild their own 4L60/65/70E transmission. Most of the 4L60E parts (apart from valve body, pump and electrical components) also apply to the 700R4, for those that have an older vehicle so equipped.
I'll edit to add and update content as I go; will bump the thread if a whole bunch of updates are made.
4L60E Teardown and Inspection
4L60E Build for High Performance
4L60E Playlist
Tech Resources
GM Technician's Guide (mostly diagrams)
4L60E Limp Mode Diagnostics
DTC P1870 TSB
TSB for Harsh 3-2 downshift (note: this condition is normal in the 4L60E and 700R4)
Parts and Machining Services for Overhaul
Starting a similar thread to the 6L80 post but dedicated to the 4L60E as countless GM cars, trucks and SUVs were fitted w/them from 1993-2013/14, including those owned by many of us (I have a 2003 Tahoe Z71). Posted below is my teardown and inspection video that covers everything you need to check for as well as a link to my 4L60E playlist that covers valve body disassembly and reassembly, full rebuild, and related topical videos. I included a complete parts and machining procedures list as well so folks have a comprehensive view of everything that needs to go into these transmissions for a proper overhaul. Lastly, I have included some tech resources and information for those that want to rebuild their own 4L60/65/70E transmission. Most of the 4L60E parts (apart from valve body, pump and electrical components) also apply to the 700R4, for those that have an older vehicle so equipped.
I'll edit to add and update content as I go; will bump the thread if a whole bunch of updates are made.
4L60E Teardown and Inspection
4L60E Build for High Performance
4L60E Playlist
Tech Resources
GM Technician's Guide (mostly diagrams)
4L60E Limp Mode Diagnostics
DTC P1870 TSB
TSB for Harsh 3-2 downshift (note: this condition is normal in the 4L60E and 700R4)
Parts and Machining Services for Overhaul
| 4L60E Parts | GM Part Number (If applicable) | Notes |
| Paper and rubber kit | This kit is also referred to as an 'overhaul kit' | |
| Clutch module | Raybestos or Borg Warner - factory level module comes with high energy 3-4 frictions | |
| 3-4 clutch steel module | Kolene steels recommended but not required | |
| Borg Warner high energy 2-4 band | Alto wide band is a good upgrade - reverse input drum must be new or resurfaced | |
| Corvette 2nd gear servo (093) | Good upgrade for all GM medium duty cars, trucks and SUVs | |
| Complete bushing kit | ||
| Sonnax wide rear sun gear bushing | Recommended for all rebuilds as the factory rear sun gear bushing likes to walk out on higher mileage units; mandatory for high performance | |
| Hardened and heat treated sun gear reaction shell | ||
| Forward thrust bearing | ||
| 3-4 clutch apply plate and backing plate | Not mandatory but often required due to severe 3-4 clutch burn up | |
| Borg Warner input sprag clutch (29 element) | Use 400 grit sand paper to reintroduce cross-hatching on outer race-sprag surface | |
| Aluminum 3-4 accumulator piston | All years take a large hole piston | |
| Aluminum 1-2 accumulator piston | Some very early 4L60Es have a large hole piston; most have small hole | |
| Borg Warner low roller one way clutch assembly | This one-way clutch is only holding in first gear thus doesn't fail often | |
| All solenoids (EPC, shift solenoids A&B, 3-2 control solenoid (93-08), pressure switch manifold assembly (93-08), wiring harness | Use OEM or Rostra only! | |
| Manual lever position sensor: Dual connector: 1996-2003 | single connector: 2004-2008 | GM/AC Delco or Rostra Good time to replace this as if it fails, you won't be able to start your vehicle | |
| Internal mode switch (2009+) | GM/AC Delco only! Good time to replace this as if it fails, you won't be able to start your vehicle | |
| Turbine (input) speed sensor (L2006+) | GM/AC Delco only!; consult dealership parts dept to confirm if yours has a turbine speed sensor Must replace this on all overhauls when equipped - you cannot replace this sensor when the trans in the vehicle! | |
| Sonnax LB4L60E boost valve kit | Install in place of worn out factory boost valve and sleeve | |
| Machining Services | ||
| Pump body and cover resurfacing and milling (pump body only) | Provide machinist your pump rotor and slide - these are selective and clearance must be as follows: - Rotor to pump body deck: .0015-.0025 - Slide to pump body deck: .002-.003 | |
| Reverse Input Drum | Check for warped surface (most are warped when they come in) - resurface to restore to as-new condition | |
| Fitzall separator plate repair kit | Will service multiple separator plates (1-2 check ball usually wears and needs a repair sleeve from the kit) | |
| Sonnax TCC Regulator valve kit (oversized) | Requires tool, base and support fixture to hold valve body as well as Sonnax bore reamer kit Use either Fitzall drop in valve for applicable year range (95-2000, 2001-2006); this valve converts the TCC apply strategy to an on-off from a PWM (pulse width modulation) Cannot be done for any vehicles with VVT or active cylinder management as the PWM must be working properly | |
| Sonnax oversized actuator feed limit (AFL) valve kit | Requires tool, base and support fixture to hold valve body as well as Sonnax bore reamer kit Worn AFL valves / valve bores will cause a myrid of symptoms and failures thus all valve bodies must be tested | |
| Corrective & Performance Upgrade Options (list not exhaustive) | ||
| Shift Kit (basic) | Transgo SK4L60E | Superior Technologies 4L60E | |
| Shift Kit (performance) | Transgo HD2 | Sonnax Surecure Kit (preferred) | |
| Transgo unbreakable pump rings (5500 RPM+) | ||
| Transgo high rate forward drum return spring kit | ||
| GM OEM five pinion front and rear planetary carrier assemblies | can be good used or rebuilt by a competent machinist | |
| Sonnax Smart Shell | Best sun gear reaction shell on the market | |
| 4L65E Input drum assembly | Induction hardened input shaft | |
| 4L65E 3-4 clutch pack kit (7 frictions and six steels, apply plate and HD backing plate) | High energy clutch material | |
| 4L70E Reaction shaft | Induction hardened splines | |
| Sonnax Smart Tech Input Drum | Expensive but as close to bulletproof as you can get for these transmissions | |
| Sonnax input drum reinforcement kit | Reinforces factory input drum for high RPM and power levels below 550 HP | |
| Raybestos Blue Plate friction module | Full race only | |
| Alto High Energy or Raybestos ZPG or Stage One friction module | Great all around street/strip | |
| Sonnax Super hold servo assemblies (2nd and/or 4th gear) | A must for heavy towing and/or hauling as well as street/strip - race | |
| CK Performance Billet pump rotor | Great for racing and other 5500+ RPM uses |
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