TH400, Turbo 400 Hydra-Matic Transmission 3L80 (M40) 3 speed General Motors

Considering overhauling your Chevrolet transmission or just need GM TH400 need parts? We provide a large inventory selection for TH400 automatic transmission overhaul kits, parts including steels, kits, solenoids, filters, solenoids. This wide selection of parts are used in the GM TH400 automatic transmission in GM model years 1965 to 1990 Chevy light duty trucks and passenger cars starting in 1965.. In addition to these kits we also supply torque converters, fluids, problem prevention kits and in most cases we can supply good take out hard parts and save you some money.

Free infomation is provided on parts illustrations, maintenance tips, overhaul tips and assistance in identifying just what automatic transmission you have in your vehicle. In addition a factory description and ratio information is available.

Parts Illustration Troubleshooting/Overhaul Manual

Maintenance Tips Overhaul Tips

Remanufactured Automatic Transmissions What transmission do I have?

Type:

The following components are available to enhance Shifting
Part Number	Qty Req	Description	Years	Price
ST34944		Shift Correction Kit		$56.96

Torque Converter ---------- Torque Converter Problem & Information For this series transmission there are MANY different possibile torque converters). When rebuilding your transmission it is always recommended that you change the torque converter. When ordering the torque converter you must supply the four digit code off of the existing unit (located on a sticker). Some of the possibities are:					Torque Converter Installation/Preparation
Code	Order Part Number		Application	Price
	GM3		1964-UP; 3 rows of ribs (not trucks or Suburbans 87-up) Low Stall; GM3 and GM8 will interchange, USS thread	$63.77
	GM8		1964-UP; 3 rows of ribs (not trucks or Suburbans 87-up) Low Stall; Metric thread	$63.77
	GM6		1964-up; 2 rows of ribs (not trucks or Suburbans 87-up) High Stall; GM6 and GM7 will interchange, USS thread	$63.77
	GM7		1964-up; 2 rows of ribs (not trucks or Suburbans 87-up) High Stall; GM6 and GM7 will interchange, Metric thread	$69.93
	GM5		1964-UP; 3 rows of ribs (not trucks or Suburbans 87-up) Low Stall; GM5 and GM9 will interchange, USS thread	$63.77
	GM9		1964-UP; 3 rows of ribs (not trucks or Suburbans 87-up) Low Stall; Metric thread	$66.99
	GM4		Variable pitch stator; VP solenoid on front pump, do not interchange with fixed pitch stator converters.	$113.83	Be sure to use our transmission cooling line flush in order to remove debris. Your cost is $11.88 order Kooler Kleen.
	J8		1977-up Jaguar May have spot welds instead of ribs, High stall stator (1750 stall); furnaced brazed	$137.85
	TC275-3L		1987-up (retro to 64) Trucks, Suburbans, Motorhomes, Furnace brazed; Allison bearings	$289.83
	TC275-6L		1987-up (retro to 64) Trucks, Suburbans, Motorhomes, Furnace brazed; Allison bearings	$289.83
Modified TH 400 torque converters are avaliable*
Heavy Duty 1500-1700	HD		Designed for heavy duty applications with stock stall speeds. Fully brazed turbine & impeller to resist loads.	Add $123.00 to above.
Low Stall 1300-1500	RV		Reprogrammed for towing applications and fuel economy. Fully brazed turbine & impeller to resist loads	Add $123.00 to above.
High Stall	HS		You may use TH350 Non-lockup torque converters to achieve a higher stall. This will require the dual bolt pattern 350/400 f;uwjee;/	Add $123.00 to above.
We supply only high quality remanufactured torque converters, cost + $50.00 core deposit.
* Modified units are available for: all TH400 converters except the TC275-3L & -6. Note: The TC290 & TC290-3l may be used for extreme duty applications.

Troubleshooting/Overhaul Manual

These manuals are typically 50 to 85 pages and contain both troubleshooting information and data to support overhaul, such as electronic data, illustrations and specific procedures and specifications. These are professional shop manuals which will give you the capability to diagnose problems, and evaluate repair options. If you decide to have your transmission overhauled at a local shop you will be armed with detailed knowledge of problems and potential fixes. This information should allow you to get the best deal. Always compare pricing for labor. If you supply the parts and ask for warranty in the end you will save money.

Fluid Recommendation:
Red Line high-Temp ATF Our Red Line high-Temp ATF --is a synthetic GL-4 gear oil for use where Dexron III is recommended. A higher viscosity allows optimal operation at 70 degrees higher temperature, providing better torque converter efficiency. Perfect for heavily-loaded vehicles. Superior stability allows high-temperature operation without varnishing valves and clutches. nverte Recommended for use after overhaul, mixing with existing fluid is not recommended! Our LubeGard "automatic transmission protectant" is recommended as an additive to improve transmission life and maintenance.		Red Line high-Temp ATF your cost $11.95 qt.

Master Rebuild Kit

Typically contains gaskets and rubber kit, sealing rings, metal/rubber clad seals, friction plates, steel plates* , front and rear bushings, filter and where applicable Band* and/or Modulator*.

*not included if listed separately

Maintenance Tips

Regular maintenance cycles and continued checking of fluid levels is critical to the life of your transmission. Operating temperature is the single most critical parameter effecting the life of the transmission. Keep the temperature down and fluid fresh helps the units typically last a very long time under normal driving conditions (no teenagers involved). We can supply a couple of aftermarket products to help you get the most out of your transmission:

Auxiliary Transmission Oil Cooler.

The Truco part number LPD4451 is an excellent auxiliary oil cooler to provide additional cooling capacity. The kit includes all parts required to mount the unit and connect to existing cooling lines. This is a typical do it yourself project. The unit typically mounts in front of the radiator. Your cost on this transmission life saving product is $54.94 plus shipping and handling.

Fluid Additive

Generally we don't recommend additives but we have found that the Lubegard "Automatic Transmission Protectant" at only $13.93 + S&H can:

• Prevent overheating, reducing transmission temperatuare up to 40 degrees F.
• Extend fluid life
• Eliminates transmission fluid foaming and oxidation
• Reduces wear throughout the transmission
• Elimates clutch chatter and torque converter shudder
• Softens and modifies harsh shifts
• Provides for smoother shifting
• Eliminates objectionable noises during shifts
• Keeps valves and governors free and frees stuck valves in valve bodies
• Raises the thermal and oxidative stability
• Only product that increases the fluids ability to transfer heat
• Contains no Ash

Always consult and follow owners manual for maintenance intervals and requirements.

ult and follow owners manual for maintenance intervals and requirements.

Overhaul Tips

Before you tear into the transmission, we suggest you first study the troubleshootin/overhaul manual, add a bottle of our "Automatic Transmission Protectant" and put a few miles on the vehicle. This just might free valves and governors that are possible stuck in valve bodies. Be sure to get computer trouble code(s), see owners manual for technique to acquire malfunction codes. This will be a great assistance in diagnosing possible problems.

Twenty-One Steps to Successful Transmission Repair:

1) Do your research locate any technical bulletins pertaining to your transmission, ask your dealers parts department for bulletins.

2) Clean the entire transmisssion, including the valve body.

3) Check pump, valve body and case for warpage.

4) Flat file pumps, valve bodies, and cases. Just a few strokes with the file to knock off high spots and handling burrs.

5) Check all pump gear clearances.

6) Check planet pinion end play and side to side motion.

7) Soak all planet assemblies.

8) Soak all friction materials for 15 - 30 minutes.

9) Make sure all steels are in usable condition or replace. Do not sand or tumble steels when used against High Energy friction materials.

10) Inspect all surfaces upon which a band will ride.

11) Replace all rotating oil control rings.

12) Check all oil control rings and rubber products in the bores for proper fit.

13) Check all major support bushings and bushings that control lub oil.

14) Pre-lubricate all bushings and thrust washers.

15) Pre-lub pumps.

16) Pre-fill torque converter.

17) Use available manuals to ensure proper specifications and clearances.

18) Set correct clutch and band clearances.

19) Take the time to set the total end play.

20) Use a torque wrench on all pumps and valve bodies.

21) Always double flush the cooling and cooling return lines to the radiator to remove particles trapped there.

Take your time, take your time, take you time!

Torque Converter Installation/Preparation

Many torque converter problems can be avoided with proper preparation:

1) Pre-thread converter bolts by hand to make sure there is no sign of stripped threads.

2) Check and clean crankshaft thoroughly. Change crank spacer (if applicable).

3) Use 320 grit sandpaper or Emory cloth to remove any metal shavings on crankshaft.

4) Check converter for any damage that may have occured during shipping.

5) Pre-fill converter with a minimum of (1) quart of transmission fluid.

6) Clean all paint off the pilot using 320 grit emory cloth.

7) Apply grease, not transmission gel, on the pilot.

8) Check flexplate for cracks and be sure there is no more than .006" run out.

9) Make sure all engine dowel pins are in place and clean.

10) Make sure all electrical ground straps are properly connected.

11) Never, Never us an impact gun to install torque converter bolts. Driving a bolt into the converter cover will create a dimple on the lockup apply surface. Lockup clutch failure will occur when the lockup piston applies against and uneven surace. Grinding off on thread length from all lockup converter bolts is recommended to avert this type of failure.

In addition to the TH400 automatic transmission parts and accessories, we also provide an impressive list of automotive after market products for car, pickup truck, SUV and 4wd repair parts and accessories that includes rear end covers, ring and pinion gears, OE clutches and heavy duty performance clutches, diesel gauge kits, exhaust brakes, re manufactured manual and automatic transmissions and both manual and automatic overhaul kits. Other products we offer for the RV recreational vehicle market include: REMCO driveline disconnects, tow bar and baseplates and auxiliary overdrive units to improve vehicle performance and save fuel. We have a complete 4 wheeling drivetrain product line including complete differential assemblies, limited slip and other solid locking positractions. We offer transmission conversion kits including the NV4500 and NV5600 as well as replacement kits for light duty GM and Jeep transmissions. You may be interested in visiting our Ford and Powerstroke Diesel page, Dodge Ram and other Jeep pages for detailed information.

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