Th350400 governor mods in the previous issue i explained how the governor plays the major role in determining the automatic shift points in drive for th350 and th400 transmissions. Th350 governor weight kit 3504468104k tsr racing products. The truck is a 71 c10 that was a 3503 speed std and is now a 350th350. Transgo kits instantly reprogram automatic transmissions for high performance and durability. I am thinking of installing a governor recalibration kit in my th350. On the th400, the governor cover is retained by four screws in a square pattern. Specialized tools needed to r n r a th350 the bangshift. Unfollow th350 governor to stop getting updates on your ebay feed.
Jd youngest son and i have calibrated his th350 to up shift at the peak power of his 350 sbc which is 5600 rpms. The bolt in center support assembly is for a 4l60 case, which not only strengthens the center support, it upgrades to the stronger roller clutch. Prior to removing the oil pump, it is a good idea to take an input shaft endplay reading. Extensometer calibration and extensometer verification to astm e83 and iso 95 needs to be performed accurately, quickly, and with sufficient calibrator resolution. There is a tool to remove the seal without removing the linkage.
Transmission wide open throttle shifts 6000 rpm th350 i am on to my 2nd th350 rebuild. If the rear axle ratio has been changed or the trans originally came from a different vehicle, the governor calibration is probably off and should be changed. Id like to pick up an overdrive auto for the highway. We decided to use one to modify our turbo 400s governor and improve its performance feel on the street. Technical manuals drum miscellaneous items chemicals and lubricants output shaft accumulator and servo components bands. Chevrolet first produced the th350 transmission for the 1969 model year. Their governor gears are excellent replacement components and they are made of premium materials to provide a precise fit with. The driven gears are the same as used on 400s and 700s so theyre not too hard to find. The governor parts are interchangeable, but the gears are different between these models. You can do this job yourself without pulling the transmission. Automatic transmission governor recalibration kits 700r4. Although the design of the th350 is fairly primitive compared to todays computercontrolled transmissions. Governor heres a quick rundown on the overhaul of the gm turbo 400 governor.
Calibration software avl cameo 4 is a proud member of the avl team suite. The coan governor recalibration kit will allow you to raise or lower, relative to vehicle speed, the points where your transmission shifts. Th350 th400 700r4 250 transmission governor springs. Gm turbo 350 transmission rebuild troubleshooting guide. Governor recalibration kits from tci will allow you to adjust the shift points of your transmission. Sonnax automatic transmission governors will restore proper function on select automatic transmissions. Governor recalibration kit, gm, th350, th400, 700r4, kit. Took it on its first road trip sunday and quickly noticed it only shifted once from low to 2nd. I was having an issue with my old gov gear and this replacement did the job. Th350 400 governor mods in the previous issue i explained how the governor plays the major role in determining the automatic shift points in drive for th350 and th400 transmissions. Th350400 shift point adjustment the 3 speed turbohydramatic 350 and its big brother the th400 were some of gms most widely used automatic transmissions from the mid 60s through the early 80s.
Th350400 shift point adjustment hoosier state chevelle. Variables such as the vehicles axle ratio and tire diameter affect the accuracy of the speedometer. A bad governor will result in a sudden loss of upshift. It uses weights and springs just like a mechanical advance mechanism in a distributor, but employs two sets of weights for low and high speeds. I have a 1975 chevy pickup with a 350 motor and a th350 transmission i have a problem with the governor in the transmission i had the governor replace because the governor got stuck in second gear wont let it go back to first gear when i stop now the new governor is. The following speedometer drive gears and driven gears are available for the 700r4 4l60 transmissions. Digital extensometer calibrator with software position. Patc sells transmission governors for 700r4, th400, th350, aod. The th350 and 400 depend on proper calibration to provide dependable operation and prevent unwanted failures.
As you leave from a stop the trans valve body or brain, senses that the road speed is low via the governor. The trick is to find the right combination of springs and inertial weights that are in the kit so that you can calibrate the governor s up shift point. It was adjusted and made a little difference with the 12, but not really the 23. Most cars and trucks with low rear end ratios will take a 15 tooth drive gear. Can you adjust the modulator on th350 to make it shift harder. In terms of performance and durability for an automatic transmission, the most important improvement that can be made is to reprogram the control assemblies. Need some good input from tranny guys or rebuilders regarding governor recalibration to raise shift points on a th 350. Th350 problem i have a 1975 chevy pickup with a 350. This kit is very useful if you have a vehicle that is very light andor has a low rearend gear ratio to adjust the shift points to best suit your needs. Well i searched but did not find how to remove the clip the holds the cover on the governor on a th350. This was installed on a small block chevy 350 with a th350 transmission. Th350 governor calibration shift points post by malibu man.
Th350400 governor mods hoosier state chevelle association. Btw, on the th350, the governor cover is retained by the spring clip, and has an oring seal. Not familiar with a th350 but wikipedia says its a 3speed tranny. Tci governor recalibration kits 326500 summit racing. This involves a process of elimination, usually starting from the simple, easytocheck items, then moving on to more difficult items in logical sequence. Woodward has incorporated decades of experience controlling engines and turbines into its suite of software products and tools. It is a powerful tool that gives you one solution to handle the. How to troubleshoot a chevy th350 transmission it still runs. Th350 governor calibration shift points don terrills. For the record, this photo is of a governor in a th350. This is the governor that commands wot upshift speeds. Will the recalibration kit allow me to make the change i want. It must be free of nicks and burrs and move freely in the bore.
Modifying transmission governor for higher wide open throttle shifts without any expensive kits. Th350 350c transmission governor th350 350c transmission. The governors in th350, th400, and 700r4 transmissions are the same. This tech tip is from the full book, gm turbo 350 transmissions. Sonnax valves and tools general motors th350 350c transmission parts automatic transmission kits gm rear wheel drive th350 hard parts transmission parts automatic transmission kits gm rear wheel drive th350 miscellaneous performance products general motors th350 hard parts. Automatic transmission governor recalibration kits gm. This kit will allow you to custom tailor your transmission shift points.
How to troubleshoot a chevy th350 transmission by john stevens j. Adjusting shift points on 1985 turbo 350 automatic i have been told that the shift points on an older 1985 turbo 350 automatic transmision can be adjusted by turning a screw inside the modulator valve clockwise, 14 turn at a time untill it shifts at the proper time. I am really new to automatics, so is this a good idea. Buy automatic transmission governor at advance auto parts. Tci automotive offers a governor recalibration kit thats designed to allow owners to adjust fullthrottle upshift speed of any turbo 350, turbo 400, or 700r4 transmission. Keep in mind you will need to drill out the hole for the roll pin to go through recommend using a drill press. This kit gives you all the necessary hardware to make the modifications and adjustments to the transmission governor. This particular th350 build is going behind a pretty powerful engine, so i will upgrade a few areas during the rebuild. Today he pulled the governor, i had a calibration kit so we popped in 1 heavier weight, but that didnt change anything that he noticed. The software products support the engineer throughout the control system lifetime, from creation to simulation to runtime operation to viewing and troubleshooting. These kits are very useful for transmission swaps, or if you have a car that is very light or has a low rear gear ratio. The first calibration program i used was colorhcfr, which is a free software package that anyone can download, and supports a wide variety of sensors.
The fully automatic transmission was equipped with three forward gears and one reverse gear. Diy th350 governor calibration changing wot shift points from 4000 to 5000 had a noticeably affect on partthrottle shifts, probably because of how i have the vacuum modulator set. Unique kits recalibrate the transmission to shift far more efficiently. Hard parts free delivery possible on eligible purchases. I tried moving the clip with a screw driver, taping it with a mallet but the clip will not move. The th350 was mainly factory installed with small blocks and the th400 with big blocks and high performance and heavier duty vehicles. Proper installation of this kit can greatly improve peak performance and drivability of your vehicle. This kit gives you all the necessary hardware to make the modifications and. Governor recalibration 19581965 full size chevrolet. Bangshift 700r4 rebuild tech part 1 bangshift 700r4 rebuild tech part 2, reassemble the last thing im going to do before i wash the case is remove the internal linkage nut and clip so i can remove the linkage and pry the manual shaft seal out. The premier site for everything to do with hot rod, customs, low riders, rat rods, and more. Troubleshooting is the stepby step process where you can logically diagnose a problem.
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