It’s all about control. The automotive world is increasingly regulated by digital electronics, and hot rodders might as well take advantage of these amenities. If you look at the progression of new cars for the last 30 years, it’s all about digital management of every aspect of the automobile — including automatic transmissions.
You are watching: Will a 4l60e transmission fit a 350
This story will look at the evolution of the 4L60E, which is essentially a digitally controlled 700-R4. We’ve done the research so you don’t have to wade through all the inaccurate chaff to pick out the seeds of the best 4L60E. We’d also like to thank Jimmy Galante at Racetrans in Sun Valley, California, for his technical guidance with this story.
Let’s start with a brief history. The original 700-R4 was built in 1982 as a Corvette four-speed automatic with overdrive. This gearbox is different because it applies an overdrive to First gear to create Second. Third gear is 1:1, with overdrive again engaged to create Fourth.
This first version was designed with a bolt-on extension housing and employed a throttle-valve (TV) cable intended to signal engine load to the transmission via throttle position, instead of a using engine vacuum. Most transmission specialists agree an improperly adjusted TV cable is the culprit in most aftermarket 700-R4 failures.
In 1993, GM wisely converted to electronic control, eliminating the cumbersome TV cable while changing its nomenclature to 4L60E. The numbers decipher like this: 4 is the number of forward gears, L (longitudinal) for rear-wheel drive, 60 equates to a maximum 6,000 pounds of gross vehicle weight (GVW), and E for electronic control. Later transmissions were upgraded as 4L65 and 4L70 for use in heavy-duty trucks.
The 4L60E has now been in production for more than two decades and has experienced multiple performance updates that affect interchangeability. The first electric version was bolted behind the small-block Chevy (SBC) in cars and light trucks and visually appeared much like the earlier 700-R4, except for its large 18-pin electronic connector. The next major change was a six-bolt extension housing in 1993, compared to the original four-bolt.
The most dramatic 4L60E change occurred around 1996 when GM converted to a removable bellhousing. This move allowed adapting multiple engine bellhousing patterns to the same case. For torque converters, the earliest 700-R4 transmissions used a 27-spline converter. Later 1984-’97 700R4 and 4L60 versions were of the 298mm family line, with a 30-spline input and a 1.70-inch diameter hub.
With the introduction of the LS engine family in 1998, later 4L60E transmissions employed a third different input, also 30-spline, with a larger 300mm torque converter that is substantially thicker (about ¾-inch) than previous versions. There followed a fourth and most recent 4L60E evolution that accommodates an input shaft reluctor that does not effectively interchange with earlier converters.
As you can see, there are multiple variations on the 4L60E transmissions that make it very easy to wander down the wrong performance path. Mistakes are easy, especially if you are mixing and matching engines and transmissions. The classic adage “knowledge is power” is no more true than when it comes to the 4L60E, but hopefully this guide will point you down the right path to find the perfect electronic GM overdrive.
Trans Length Chart
This TCI chart calls out the different 4L60E transmissions and their lengths compared to a typical TH350. The bellhousing pattern refers to either small-block Chevy (SBC) or LS Gen III/IV engines.
|Transmission||Overall Length||Bellhousing to Crossmember||Bellhousing Pattern|
|TH350 (6” tailshaft)||27 11/16”||20 3/8”||SBC|
|4L60E (1993-’96)||30 3/4”||22 1/2”||SBC|
|4L60E ’96 – later w/removable bellhousing||30 3/4”||23 3/16”||SBC|
|4L60E ’98 – later w/ LS style bolt pattern||31 5/32”||23 19/32”||LS|
You can quickly identify later 4L60E versions by the RPO code cast into both sides of the case. It’s best to use more than one means to identify a specific transmission to avoid possible individual year idiosyncrasies.
|Trans||Code||Factory Torque Ratings||Ratios||Weight*|
|4L60E||M30||380 lb.-ft.||3.06||1.62||1:1||0.70||160 lbs.|
|4L65E||M32||430 lb.-ft.||3.06||1.62||1:1||0.70||160 lbs.|
|4L70E||M70||495 lb.-ft.||3.06||1.62||1:1||0.70||160 lbs.|
|4L80E||440 lb.-ft.||2.48||1.48||1:1||0.75||180 lbs.|
|4L85E||685 lb.-ft.||2.48||1.48||1:1||0.75||182 lbs.|
*Weight with fluid, minus torque converter.
|Chevrolet Perf. 4L65-E LS trans – new||19260380||Summit Racing||$1,867.99|
|TCI 4L60E SBC trans, 30 spline||371016||Summit Racing||$2,532.97|
|Fragola ¼ NPSM to -6 male fitting, ea.||481670-BL||Summit Racing||$ 6.97|
|Jiffy-tite quick-disconnect -6 cooler line kit||200T5J||Summit Racing||$97.51|
|Chevrolet Perf. 4L60E trans adapter kit||19154766||Summit Racing||$249.97|
|B&M 4L60E trans controller||120001||Summit Racing||$775.17|
|Chevrolet Perf. 4L60E trans controller||19302405||Summit Racing||$1,109.97|
|Compu-Shift II 4L60E trans controller||Call||HGM Elect.||$1,034.00|
|Painless Perfect TORQ 4L60E controller||86501||Summit Racing||$645.99|
|TCI EZ-TCU 4L60E controller||302820||Summit Racing||$614.97|
|Powertrain Control Systems Simple Shift||TCM-5311||PCS||$729.00|
|TCI longer dowel pins for spacer plate||930055||Summit Racing||$14.97|
Sources: Abbott Enterprises;abbott-tach.com, Auto Meter Products;autometer.com, B&M Performance Products;bmracing.com, Chevrolet Performance;chevrolet.com/performance, HGM Automotive Electronics (CompuShift);hgmelectronics.com, Painless Wiring;painlessperformance.com, Powertrain Control Solutions;powertraincontrolsolutions.com, Speedhut;speedhut.com, TCI;tciauto.com