Since the first gear reactive force is evenly distributed around the periphery of the case, the types of mechanical and some times violent failures that have plagued other competition transmissions [ vague ] are rare. The THM was the first three-speed, Simpson-geared automatic to use overrunning clutches for both first and second gear reaction, a feature that eliminated the need to coordinate the simultaneous release of a band and application of a clutch to make the gear change.
Owing to this feature, as well as the use of a large, multi-plate clutch to provide second gear reaction, the THM is able to withstand very high input torque and an enormous number of shifting cycles, as would be encountered in frequent stop-and-go driving.
As a result, it has met with considerable success in commercial vehicle applications. Transmission fluid cooler line connections are found on the right-hand side of the THM The lower connection is the cooler feed, and the upper connection is the return. Four-wheel drive truck applications used 3 various shorter output shafts that coupled with a female transfer case input shaft.
Early transfer cases mated directly to the THM with a cast-iron adapter, usually a vertical oval shape. Later models used a circular style iron adapter which is generally considered the stronger of the two. The shortest was used with the NP transfer case. The Turbo Hydra-matic was first used in model cars. It was developed jointly by Buick and Chevrolet to replace the two-speed Super Turbine and aluminum-case Powerglide transmissions.
So, although it carries the Turbo Hydra-matic name, the Hydra-matic Division of General Motors had little, if anything, to do with its design. Although it uses the same torque converter as the THM without variable pitch stator it has a familial resemblance to the aluminum Powerglide from Chevrolet [ according to whom? An important difference in the THM compared to the THM is that there is no fixed center support midway through the geartrain; this difference in layout would have permitted the THM to be adapted to the Corvair where the drive and driven ends are the same, but this feature was not exploited.
Air-cooled versions with a baffle on the torque converter and air intakes cast into the bellhousing of the THM appeared mid in the Chevrolet Vega and Nova 6. One THM weak point was excessive end-play between the pump and center support and resulting wobble of the direct clutch drum due to both the end play and use of a relatively narrow bushing in the drum.
This weak point can be addressed by using an extra thrust washer between the planetary gear and direct clutch to remove the end play and using a wider aftermarket bushing in the direct clutch drum. This weakness can be addressed by using an inexpensive aftermarket case saver kit.
Four-wheel drive truck applications for the THM used an iron adapter that mated it to the transfer case directly, similar to the THM The THM adapter was cast iron and used a sliding sleeve to couple the transmission output shaft to the transfer case input shaft with a steel coupler sleeve that was splined to accept both shafts and couple them together. For the model year, a lock-up torque converter was introduced which coincided with the new EMC control of most GM cars; this version is the THMC, which was phased out in in GM passenger cars for the R4.
The standard TH is still very popular in drag racing. The THM was usually coupled to smaller displacement engines - the largest a third generation Chevrolet inline six found in the Nova and Camaro and 75 model year only. However, this transmission was notorious for its failure rate [ citation needed ] when used behind too large an engine - the largest being the Oldsmobile 5. This setup was later incorporated into the THMR4.
For the model year, the R was introduced. The components which were prone to failure in the THM were improved, and in the later s this transmission was used with high-power applications — primarily the Buick Grand National and the Pontiac Firebird Trans Am Indy Pace cars.
The R was configured with several different torque converters depending on the vehicle application. However, Rs share mounting locations with the TH Under the new designation, the "4" stands for the number of forward gears, the "L" for longitudinal applications rear-wheel-drive , and the "60" is the strength rating less than the 4L For example, 80 is stronger than 60, which is stronger than 40, etc. A 4LE can handle more torque than a 4LE.
The "E" denotes electronically controlled shifting. The 4L60 however is hydraulically shifted based on governor pressure and throttle valve TV cable position. The Camaro, Corvette and Typhoon were equipped with the last production R4. The last design change of the R4 was an added checkball to the valve body. In electronic controls were added, and it became the 4LE.
In , an updated version — the 4LE, was introduced. The 4L70E transmission is the same as a 4L65E with a speed sensor located in the pump. The tailshaft housing is held onto the main case by four bolts the bolt spacing is similar to the THM , and 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 in 51 cm overall. Transmission fluid cooler lines on the R4 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. The original version of the transmission had a spline input shaft shared with the THMC and R which was a common failure point.
In , the R4 designed for use behind Chevrolet small block V8s received a spline input shaft similar to those found on TH transmissions and which also used a different torque converter than its 2. Between and , internal components, from the ring gear to the oil pump housing, were updated, ending with the auxiliary valve body for s manufactured after October The early designs simple on or off lockup function while the later design can regulate the apply pressure as to not feel the lock up occur.
GM added a fifth solenoid to the valve body, called the PWM solenoid. In , GM introduced a redesigned 4L60E transmission case that incorporated a bolt-on bellhousing and a six-bolt tail housing. The majority of and later applications of the 4L60E were two-piece cases i. Both transmissions are the same internally. Also in , GM changed the solenoid to a different style which makes it not interchangeable with any previous models. For the model year GM trucks, there were two versions of the 4L60E: one had a bolt-on bellhousing, the other did not.
In total, there are nine different bolt-on bellhousings. The bolt-on bellhousings used on the 4. Skip to content. Are you looking for slitting and rewinding companies or material slitting services? We excel in material rewinding services. We rewind and unwind material conversion while rewinding and unwinding material. Material die cutting services are integral for industrial manufacturing.
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