1999 4L60 in a 2004

Ed's Automotive

Original poster
Member
Jan 22, 2020
3
Florida
Hey folks. I have a customer that brought me a 2004 Trailblazer 4x4, slips when it tries to shift into 3rd but if you get it going fast enough in 2nd then it skips it and goes to 4th. I did a 2-3 shift solenoid and didnt fix it, colleague says 3/4 clutch pack is going out. I have a donor 4L60 from a 1999 Tahoe that a friend left here hes willing to sell, I just need to know what, if any, modifications I'll need to make to be able to use it. Will it be a direct bolt on with no problems? Swap bell housings? Different torque converter? Thanks for any help.
 

mrrsm

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Oct 22, 2015
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Welcome to GMT Nation...

With all of the complexities and variations between the 4L60 and 4L60E Transmissions... Having the "Two Reference Bibles" for immediate research whenever Mixing and Matching between the Truck and Car Line Series of these Transmissions will save you a TON of Headaches.

Knowing what the Specific Transmission and sub-assembly Measurements are will prevent any attempts at installing anything that simply WILL NOT FIT. These two ATSG GM 4L60E Service Manuals are available for around $25.00 a piece on Amazon and tell the complete story:


ATSG4L60EUPDATEMANUAL1.jpgATSG4L60EUPDATEMANUAL.jpg

These other issues are the important considerations:

(1) Unless you have posted incomplete information... the 4L60 Transmission is NOT the same as the 4L60E as the former is used for example, in the 1993 Chevrolet Camaro Z28 and has NO Electronic Controls built inside and out. The 4L60E has a Park Neutral Switch on the Driver's Side Shift Linkage Armature and an external 20 Pin Ovate Connector on the upper Passenger Side of the case.

(2) The 2002-2006 Chevrolet Trailblazers and Envoys use the GM Bell Housing Part # 24220855 for the 4L60E 4L65E Transmissions mounted to the GM Atlas 4.2L Engines as part of its Split Case Design. The Outer Bolt pattern is fitted for (11) 15mm Fasteners and the interior Bolt Pattern is designed for (8) Torx Plus Fasteners under extreme TIGHT conditions holding in the Transmission Fluid Pump and Imput Shaft supporting the Torque Converter..

(3) Disassembly of the Split Case design on the 4L60E to remove the (8) Interior Torx Plus Fasteners WILL require the use of a TORX PLUS #50 BIT with a 3/8" Square Drive as shown in the linked images and place for purchase. If you attempt the removal of those Fasteners with a regular Torx Drive Bit... it will walk off the center of those Bolts and ruin them.



TORXPLUS50BIT1.jpg

Other similar offers can be seen at this Link:


(4) Unless the (4) Alpha Numeric Code Numbers marked on the White Label Glued to the Top of BOTH Transmissions are Identical Matches... Use the Original Torque Converter from the Original 4L60E Transmission and NOT the one from the Tahoe.
 
Last edited:

Ed's Automotive

Original poster
Member
Jan 22, 2020
3
Florida
Welcome to GMT Nation...

With all of the complexities and variations between the 4L60 and 4L60E Transmissions... Having the "Two Reference Bibles" for immediate research whenever Mixing and Matching between the Truck and Car Line Series of these Transmissions will save you a TON of Headaches.

Knowing what the Specific Transmission and sub-assembly Measurements are will prevent any attempts at installing anything that simply WILL NOT FIT. These two ATSG GM 4L60E Service Manuals are available for around $25.00 a piece on Amazon and tell the complete story:


View attachment 92823View attachment 92824

These other issues are the important considerations:

(1) Unless you have posted incomplete information... the 4L60 Transmission is NOT the same as the 4L60E as the former is used for example, in the 1993 Chevrolet Camaro Z28 and has NO Electronic Controls built inside and out. The 4L60E has a Park Neutral Switch on the Driver's Side Shift Linkage Armature and an external 20 Pin Ovate Connector on the upper Passenger Side of the case.

(2) The 2002-2006 Chevrolet Trailblazers and Envoys use the GM Bell Housing Part # 24220855 for the 4L60E 4L65E Transmissions mounted to the GM Atlas 4.2L Engines as part of its Split Case Design. The Outer Bolt pattern is fitted for (11) 15mm Fasteners and the interior Bolt Pattern is designed for (8) Torx Plus Fasteners under extreme TIGHT conditions holding in the Transmission Fluid Pump and Imput Shaft supporting the Torque Converter..

(3) Disassembly of the Split Case design on the 4L60E to remove the (8) Interior Torx Plus Fasteners WILL require the use of a TORX PLUS #50 BIT with a 3/8" Square Drive as shown in the linked images and place for purchase. If you attempt the removal of those Fasteners with a regular Torx Drive Bit... it will walk off the center of those Bolts and ruin them.



View attachment 92822

Other similar offers can be seen at this Link:


(4) Unless the (4) Alpha Numeric Code Numbers marked on the White Label Glued to the Top of BOTH Transmissions are Identical Matches... Use the Original Torque Converter from the Original 4L60E Transmission and NOT the one from the Tahoe.

While most of that info is pretty consistent, from what I have gathered from other sources I should be able to use this donor transmission on any vehicle with the early 2 piece design. I guess Ill just have to look at them and see how close it is since no matter where I look there is no "gospel" on the matter, everyone has different ideas on what changes happened and when.
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,641
Tampa Bay Area
The Two Manuals mentioned above can be taken as "Gospel"...
 

Ed's Automotive

Original poster
Member
Jan 22, 2020
3
Florida
The Two Manuals mentioned above can be taken as "Gospel"...

Sorry, I didnt see the small part at the bottom of your original post about the torque converter. So, I can use the older transmission on the newer car if I swap the TC or do I need to swap the bell housing as well? I know the much newer one with the updated larger TC isnt compatible but I hear swapping the housing and converter will work on the other ones. Yes, its a 4L60E and not the 4L60, of course
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,641
Tampa Bay Area
In the absence of having those two ATSG 4L60E Transmission Repair Manuals at hand... It sounds like your Best Course of Action is to make a call to a Trusted, Local Transmission Repair Shop and have all of your Transmission sub-sets of the contrasting Years-Makes-Models and Part Numbers right at hand to get a definitive answer ...from a Professional.
 
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