Discussion in 'Mechanic's Corner' started by gmctrucks, Sep 6, 2011.
READ THE VERY END OF THIS WRITE UP.
Home Forum Register FAQ Members List Today's Posts
700r4 / 4l60 transmission information/ history
By Onimun - Posted on March 3rd, 2008
The Turbo-Hydramatic (TH) 700R4 automatic overdrive transmission was introduced to Chevrolet vehicles in 1981 for the 1982 model year vehicles.
It was introduced to the larger car (B-body and similar) and truck lines as the TH-2004R was introduced to the car line. The 200 was given a "universal" bellhousing bolt pattern for its ability to bolt to different engines (both the Chevy and B-O-P-C engines).
The 700 came in two bellhousing bolt patterns -- the standard "Chevy" which includes all smallblock engines from 262 to 400 cubic engines (and the later "Vortec" series engines and their derivatives), the big blocks from the truck only 366 to the 502, and the new ZZ572. This bellhousing pattern was also used for the 6.2 and 6.5 liter V-8 diesel engines, and it will also directly bolt up to the 3.3 liter 200 cubic inch, the 3.8 liter 229 inch V-6, and the 4.3 liter 262 cubic inch engines.
And then there was the smaller bellhousing bolt pattern used on the 2.5 liter (151") 4-cylinder, the 2.8 liter (173") V-6, and the 3.1 liter (189") V-6 engines.
The TH-700R4 was also offered in a 2 wheel drive version AND a 4 wheel drive version. The 2WD had a longer tailshaft and a housing including a bushing to support it along with containing a speedometer drive housing. The 4WD version had a much shorter tailshaft which was to be supported by the adapter and transfer case input shaft bearing, the 4WD speedometer was driven from within the transfer case rear output shaft housing. The only other difference I have found here is that the torque converter cover (dust cover) for the 4WD version was made of cast aluminum instead of stamped steel or molded plastic, and it used much larger bolts to attach to the transmission, as it also made provisions to attach strut rod reinforcements from a bracket that mounted under the motor mounts to the lower portion of the cast aluminum dust cover.
There were also a few changes made to the V-8 model 700 to give it the ability and dependability to be installed into the Chevrolet Camaro and Corvette -- and in certain cases the Corvette version received even more enhancements.
There were various differences in the same model -- transmissions needed to be able to be used with the different engines and the same transmission; obviously the 200 inch V-6 will have a bit of a problem driving the 700 that was designed to be bolted behind a 6.5 turbo diesel, or a big block engine.
The gearing for the 700 is:
First - 3.059
Second - 1.625
Third - 1.000
Fourth - 0.696
Reverse - 2.294
OR -- Rounded off to 3.06, 1.63, 1.00, .70, and 2.29.
Like I stated before the 700R4 was introduced in 1982, this transmission had a 27 spline input shaft, and many cumulative problems and bugs that had given the 700 a reputation that it wasn't reliable or desirable. It was revised to include many upgrades and changes that changed its reputation a little -- it was given a 30 spline input shaft, many internal redesign modifications and deemed to be a better version.
Without pictures, the 700 can be identified by the oilpan having a rectangular shape being longer front-to-rear than side-to-side and held to the transmission by 16 bolts, 3 bolts front, 3 bolts rear, 5 bolts left side, and 5 bolts right side.
The tailshaft housing is held onto the main case by 4 bolts, and from my own experience uses a square-cut o-ring seal, and not a gasket. The typical width of this transmission where it bolts to the engine is 20 inches overall. From the engine/trans mating surface to the crossmember mount bolt is 22-1/2 inches, and engine/trans surface to output shaft housing mating surface is 23-3/8 inches overall, with the tailshaft housing typically measuring 7-5/8 inch.
Transmission fluid cooler lines: on the 700R4 the bottom fitting on the right side of the transmission is the "out" line to the cooler and the top fitting is for the return line from the cooler. These fittings are 1/4-inch pipe thread, and CAN include an adapter from the factory for threaded steel lines in an SAE size.
The transmission fluid pressure readings should be in the ranges of the following numbers (psi):
The main case is made of cast aluminum and the 700 typically weighs 155 pounds.
All versions of the 700R4 transmissions can be affordably rebuilt with stronger components in nearly every area. Additionally, shift improver kits are available to provide firmer, quicker shifts -- reducing slippage, heat and clutch wear. There are also many styles of torque converters to better configure the transmission for off-road use.
In 1993, the designation of the 700R-4 changed to 4L60. A later version of this transmission, the 4L60E, is an electronically controlled variation, utilizing a reluctor ring (similar to that in an ABS application) and magnetic pickup, together called the Vehicle Speed Sensor (VSS). The transmission requires this feedback to map the shift points. In 1998 the 4L60E was redesigned to include a removable bellhousing and a shorter main case length, along with a 6-bolt tailshaft housing as opposed to the 4-bolt earlier configuration.
Duramax also has the same bolt pattern...
94 was a transition year for the 4L60E. Some had non PWM (pulse width modulated) front pumps. The front pump will say PWM cast into it at about the 10-11 o'clock position if it is one. with that, the electronics in the trans will be different with PWM/nonPWM transmissions.
I sold the Trans guys for $250.00 dollars the guy is super happy with it.
I have a 95 and need a rebuild. I've been talking to every transmission shop amd parts house in central Texas and they have all told me this:
95 was the first year of the electronically controlled 4l60 making it the 4l60e
Nothing prior will work because the computer is programmed with the transmission.
In 96 the vortec was introduced so the wiring harness of a 96 or newer wont work on the 95 trans either. I've come to the conclusion that I will rebuild it myself with a kit and a beast sunshell. I dont have the money to shell out for a new one or a rebuild. Not for that old truck.
Look at it this way. If you rebuild it, at least you know it was done right and can feel good driving your truck, knowing that fact.
Separate names with a comma.