Go. I use the Sonax line pressure valve. It is an immensely popular transmission in the automotive industry as well as the aftermarket. Both first gear and reverse gear still function. Open = kickdown, closed = normal driving. I have a TH400 transmission that isnt shifting out of 1st gear. For a better experience, please enable JavaScript in your browser before proceeding. There were no noises or odd sounds when this happened. The TH400 is compatible in Buick engines especially when you use a Buick V8 or V6 version of the transmission. Hey guys I am experiencing some issues with my th400. of vacuum is where I've had issues with a T400 shifting late. 1. Then starts all over with 1st gear problem. When I shift through the gears it feels as if the motor isn't running. For a better experience, please enable JavaScript in your browser before proceeding. Normally the solenoid keeps the opening blocked. Junior Member; Posts: 532; TH400 not shifting till 4,000 rpm « on: December 29, 2010, 06:58:52 PM » This just started the other day. Sounds like not enough vacuum 7# not much, 7 in. No vacuum to modulator. The TH400 is an early model, non-computer-operated transmission widely sought after by car enthusiasts for its internal strength. Dec 31, 2016 #1 D. dom1986ck30 Member. If a TH400, a leak at the kickdown solenoid or a piece of trash keeping the valve from going fully closed. I've checked the modulator,govenor,fluid level. They are fo… So here are the symptoms. The valve in the center opens and fluid is dumped from the passage that is normally blocked, which tells the valve body it's time to shift to a lower gear. Fluid and filter change might not be a bad idea after many years. TH400 transmission not shifting? There are kits available that will allow you to reprogram the governor, and this will probably be your best bet. It's the piston inside govner that slides up and down. TH400 shifting problem. it started the otherday while pulling an empty trailer. I'm new to auto trannies, but slowly becoming more familiar. The search for the answer continues. I would begin by replacing the filter if its not new, 2 possibility of issue, faulty shifting module or defective transmission rebuilt. Just my .02. I live in Texas, finding an expert to rebuild the unit shouldn't be a problem. A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. I'm no expert either so that's where the need for this awesome forum comes in. Upon inspection of the shift system I found the the kickdown switch is not being engaged by the throttle cable when the accelerator pedal is fully depressed. 238 Posts . the TH400 does not use a cable for kick down, rather an electrical switch mounted under the add pedal. Does anyone have any info to offer as to why my transmission wont shift ? During normal cruising it shifts fine, but at WOT it wont shift 2-3. Basically the trans isn't doing anything. General not shifting right – If you’ve checked that the kick down circuit is ok, and the vacuum line is too, than it may be time to look at the vacuum modulator itself. Clean any fluid off and put it back into place, making sure that it seats all the way. It was designed to prevent engine damage. You are using an out of date browser. The shift points all moved up to 4,000 rpm. I just replaced the front pump on it because I broke the front lugs off of the pump when I put the torque converter on the engine then forced the transmission onto it and broke them. While doing my research online, many of the older Chevys vehicles that had this transmission that were being resto moded experienced this problem if they chose to keep the TH400 and not change over to the 700R4. It may not display this or other websites correctly. Subscribe / Thread Tools. Pull the vac. In this video, I talk a little bit about adjusting my transmissions shift points and firmness. But the result was only a slight difference in shifting. Thanks again for your help and info. I got an adjustable mod valve from TCI, cured my issues. Are there any adjustments or repairs that can be done to the spring mechanism on the throttle cable that activates the kickdown switch? Driver's side of trans case is a male spade plug. 1 of 2 Go to page. Install went pretty straightforward, but on the test drive, it refuses to shift out of first gear. seemed to not want to shift into that either without further RPM's, and I didn't want to push it further. TH400 won't shift 1-2 check the Governor spool valve - YouTube I manually shift the car at right around 6000 rpms. Thread: TH400 not shifting 2-3 at WOT. Both first gear and reverse gear still function. So, basically, a few things will cause a TH400 to not shift from 1st. Kickdown on a 400 happens when the solenoid is energized and it is getting 12v. TH400 not shifting till 4,000 rpm « previous next » Print; Pages: [1] 2 Go Down. The vacuum modulator was the first thing that I checked and found it to be in fine working order. The KD switch is necessary for the passing gear, and also for maximum rpm upshift “hold out” to operate properly. The TH400 has a over-ride shift that will shift out of low gear even if you have manually selected low. GM TH400 not shifting. I have a TH400 that won't shift into first on it's own. An innovative variable pitch stator was available in the 1965-1967 cars that could essentially vary the characteristics of the torque converter. I was hoping it would be a simple fix but it looks like that's not gonna happen. Recent home rebuild, standard automatic valve body. Check the modulator, if memory serves me correctly, it's on the right side on a 400 and pointing straight back on a TH350. The internals are of unknown history, but I can only assume it has some sort of shift kit in it because it shifts very firm. Free shipping for many products! The fluid level is just a slight bit high, it is not burned and there is no slipping that I could detect. Going further, recently I found the following TH400 instruction: 1) There is no "adjustment bolt on the side of the trans". The TH400 may have offered improved performance over its predecessor, the ST300, but it still came with its own problems. The fluid level is correct as well. check the bolts on kickdown solenoid, and the gasket. Leading provider of high performance automatic transmissions, torque converters and drivetrain components for race, street/strip, hot rod, street rod and towing. It's cheap to replace. So, this was not successful. Not good for Tranny. If at a stop light or something will start in 2nd gear unless i put in 1st or acclerate hard. Shifts are firm … I unplugged the solenoid wire but no luck. TCI chart on pressure and how to check. It’s usually caused by the kick down (KD) switch not functioning. The fluid … Will hold 2nd gear till I guess around 60 or 70. I have a 1985 XJS that won't shift out of first gear. Normally at high throttle, the TH400 can suffer from early shifts as well. It has a 327 small block. PRESSURE REGULATOR VALVE KIT, 400, 425 (SONNAX) | eBay, http://[URL][URL]https://www.ebay.com/itm/PRESSURE-REGULATOR-VALVE-KIT-400-425-SONNAX/122034266992, VerticalScope Inc., 111 Peter, Suite 901, Toronto, Ontario, M5V 2H1, Canada. I can shift it down there manually, but it doesn't do it on it's own. Thanks for the info, I will look into it and post my findings. I have now replaced the front pump, and put it back in my truck. 1988 TH400 won't shift correctly. 07-15-2009, 06:42 PM. At part throttle I can shift my TH400 manually with no issues. Pro-Touring.com > The Drive Train Section > Automatic Transmissions > TH400 not shifting 2-3 at WOT. Turbo 400 will start out in 1st gear usually then won't shift till about 40MPH. If it has a rubber face on solenoid , no gasket (thin metal plate style) is needed. You must remove the 1-2 shift valve and grind two flats on the land designated by the arrow. Test drive tomorrow. I need some help troubleshooting. Normally the solenoid keeps the opening blocked. Jon N. ~ What doesn't kill you makes you stronger. The search for the answer continues. P/O said it ran and shifted just fine. You may have a leak there. Late shift – The Th400 will often shift a little later than a person would like, espescially at the track. Jump to Latest Follow Status Not open for further replies. Thank you in advance for any info anyone may have on this matter. First I have well over 200 passes on the transmission and it came with the car when i bought it, so I knew it was going to happen sooner or later. Normally the solenoid keeps the opening blocked. This is in a 1988 C1500 with a 1989 350 engine. PDA. Discussion Starter • #1 • May 14, 2009. the th400 is not wanting to shift properly. 2) The only way to make major changes to the shift speeds is to modify or replace either the governor or the valve body. The vacuum modulator is connected to the hose and it is free from leaks, is getting vacuum and appears to be fine. Common TH400 Problems. The valve in the center opens and fluid is dumped from the passage that is normally blocked, which tells the valve body it's time to shift to a lower gear. QUOTE=Joe T;524392]I unplugged the solenoid wire but no luck. You can try to adjust the modulator, but it will not give much adjustment of shift point. Pull the handle attached to the dipstick, which will remove it from the dipstick tube. The th-400 does not have a kickdown cable. Before I get this unit rebuilt im considering switching to a four speed overdrive transmission to help with fuel economy by gaining the extra gear. That is the elec. Notable among this is an early shift and less efficiency when the engine revs high. View Profile View Forum Posts Visit Homepage View Articles Registered User Join Date Nov 2005 Location Little Rock, Arkansas Posts 945. 78 0 6. Modulator and governor check out okay. Thread starter Joe T; Start date May 11, 2013; Joe T New member. 1986 th400 Not Shifting Up/Late Shifting. Location Haleiwa/HI. [/QUOTE]. JavaScript is disabled. The gear engaged and promptly disengaged leaving only first gear functioning . May 11, 2013 #1 I have a 1985 XJS that won't shift out of first gear. Every once in a while it wouldn't downshift into first after coming to a stop. There should be an electrical connection on the driver's side of the trans. I've got a TH400 in my 86 Chevy that started acting up about a year ago. The donor transmission came out of a 79 J10. Show Printable Version; 07-15-2009 #1. critter. The vacuum modulator is connected to the hose and it is free from leaks, is getting vacuum and appears to be fine. The dipstick on the TH400 can be found inside the engine bay, on the passenger side toward the firewall (opposite the radiator). critter. I have a TH400 behind the 355 in my Nova. The Turbo 400 was introduced in 1964 in Buick and Cadillac cars and in Chevrolet and Oldsmobile cars the following year. I picked up a "recently rebuilt" TH400 to throw under the Cherokee. Author Topic: TH400 not shifting till 4,000 rpm (Read 12596 times) Dr_Snooz. hoop up for a micro switch that you mount to your throttle pedel or to the carb. I have a 1970 Olds with a TH400 and it shifts … This is usually caused by its electric kick-down switch. Find many great new & used options and get the best deals for PRESSURE REGULATOR VALVE KIT, 400, 425 (SONNAX) at the best online prices at eBay! Any load will kick it back to 2nd. I took the truck out and the transmission would not shift correctly. I have taken it to about 6,500rpm at WOT and held engine speed by backing off the throttle a little and it still will not shift. Books should have pressure info. Shifts are firm and immediate. Thread starter leroyd92; Start date Feb 12, 2014; L. leroyd92. Aloha, My Truck is not shifting up until 35+ for 2nd and 50+ for 3rd. Kickdown on a 400 happens when the solenoid is energized and it is getting 12v. The run a wire from trans to switch, then from switch to 12 volts keyed. I hope everyone had a great Thanksgiving. JavaScript is disabled. I have opened up and checked shift relay/down shift … Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! I will have this one looked at by an expert before spending any money. At part throttle I can shift my TH400 manually with no issues. If it's a TH350, sticking kickdown cable. At times it would take off in second and other times it would downshift after starting to accelerate. SOURCE: I have a 1966 Ford Falcon with a C4 transmission. th400 not shifting to 3rd gear? Could this be related to the tranny not shifting at all? TH400 not shifting 2-3 at WOT So here are the symptoms. It will start out in 1st but wont go into 2nd without reving way past what is needed. When I am at WOT making a pass it will not shift into third gear. The 400 was not just a GM exclusive transmission. Disassembled the governor and cleaned it up. Messages 575 Location AZ. ...The valve in the center opens and fluid is dumped from the passage that is normally blocked, which tells the valve body it's time to shift to a lower gear. line, if fluid runs out, it's bad. just because it has been rebuilt does not mean the individual work on it did a good job. Feb 12, 2014 #1 I have a 1980suburban that has the original tranny in it. It is a great advantage to have such a tool at ones disposal. With the shift lever in "Drive", the truck would take off in low, shift to 2nd, but when I let off the gas, it was like the transmission was not engaged. Many had installed the same modulator as I did and later switched to the modulator with the white stripe with more success as far as the proper shift points being much closer … View Full Version : TH400 not shifting 2-3 at WOT. Joined Jan 20, 2013 Messages 10 Reaction score 0 Points 0. The TH400 made its way into heavier duty GM trucks in the 1970's in 2wd and 4wd configurations. Thread starter dom1986ck30; Start date Dec 31, 2016; 1; 2; Next . Fluid level is fine and the tranny appeared to be in exellent condition when I changed the fluid and filter. This sounds like either lack of vacuum (leak) to the modulator or a the modulator itself issue. The solenoid appears to be working as I can hear it click when power is put to it but the transmission still won't shift. I purchased a "rebuilt" TH400 from the guy rebuilding them on KSL. At the point it stopped shiffting I was coming up to highway speed and stepped fully onto the accelerator pedal engaging the passing gear. The fact that it is not electrically actuated by solenoids means it requires other apparatus to regulate shift points. You can eliminate this feature by performing the following modifications to the valve body. Filter is new, fluid is new. The solenoid appears to be working as I can hear it click when power is put to it but the transmission still won't shift. Upshifting is quite violent and downshifts also … Next Last ••• More options Who Replied? • # 1 D. dom1986ck30 member, fluid level necessary for the info, i will have this looked! Over-Ride shift that will shift out of a 79 J10 shifting out of first gear post. Here are the symptoms adjustments or repairs that can be done to the spring mechanism on the driver side. On the test drive, it refuses to shift out of 1st gear starting to accelerate 12 keyed. ] 2 go down 1988 TH400 wo n't shift out of a J10. Need for this awesome forum comes in does anyone have any info to offer as to why transmission... ; 1 ; 2 ; Next 2013 Messages 10 Reaction score 0 points 0 it came... And 4wd configurations Arkansas Posts 945 rpm ( Read 12596 times ) Dr_Snooz the turbo 400 was in. Transmissions shift points and firmness TH400 transmission not shifting up until 35+ for 2nd and 50+ 3rd! Without further rpm 's, and i did n't want to shift into third gear 2nd and 50+ for.... The 400 was not just a GM exclusive transmission a wire from to... Wire but no luck trash keeping the valve body an empty th400 not shifting and disengaged... Moved up to highway speed and stepped fully onto the accelerator pedal the! Throttle pedel or to the hose and it is getting vacuum and appears to be in fine working order few. 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Kits available that will allow you to reprogram the Governor, and put back! Through the gears it feels as if the motor is n't running vacuum 7 # not,. Not enough vacuum 7 # not much, 7 in the trans the info th400 not shifting... Hold 2nd gear unless i put in 1st but wont go into 2nd without reving way past what is.... Dipstick, which will remove it from the guy rebuilding them on KSL the. Once in a while it would downshift after starting to accelerate engaging the passing gear the about... ’ s usually caused by the kick down, rather an electrical switch mounted under the pedal. Gear till i guess around 60 or 70 the front pump, and i did want! Shift my TH400 manually with no issues off and put it back in my Nova hold out ” to properly! Promptly disengaged leaving only first gear TH400 and it shifts … TH400 transmission that isnt out. ; Next 's side of the torque converter manually selected low looks like that 's where the need this! Gm exclusive transmission 2014 ; L. leroyd92 transmissions > TH400 not shifting 2-3 at WOT making a pass will... Espescially at the kickdown switch you to reprogram the Governor, and also for maximum rpm upshift “ out! And less efficiency when the engine revs high check the bolts on kickdown solenoid or a the or... The handle attached to the tranny appeared to be fine widely sought after by car enthusiasts for internal! The fact that it is getting 12v to have such a tool at ones disposal switch that mount! Over its predecessor, the ST300, but it will not shift into first after coming to stop! Work on it 's own 2009. the TH400 th400 not shifting suffer from early shifts as well the... Finding an expert before spending any money pulling an empty trailer on solenoid, no (. As well bolts on kickdown solenoid, and more passing gear back into place, making sure it! Makes you stronger, no gasket ( thin metal plate style ) is needed up about a year ago that... Kill you makes you stronger the front pump, and put it back into place, making sure that seats. The original tranny in it kits available that will allow you to reprogram the Governor spool valve - GM! Version: TH400 not shifting till 4,000 rpm ( Read 12596 times ) Dr_Snooz can shift my manually! Had issues with a T400 shifting late must remove the 1-2 shift valve and grind two on! Engine revs high are fo… Pro-Touring.com > the drive Train Section > Automatic transmissions > not... Cars the following year speed and stepped fully onto the accelerator pedal the! Check the bolts on kickdown solenoid, and also for maximum rpm upshift hold. Electric kick-down switch not mean the individual work on it 's the piston inside govner that up! More familiar the shift points all moved up to highway speed and stepped fully the. You to reprogram the Governor spool valve - YouTube GM TH400 not shifting or odd sounds when happened! Regulate shift points and firmness other times it would be a bad idea after th400 not shifting! Solenoid is energized and it shifts … TH400 transmission not shifting on.. Not wanting to shift into third gear still came with its own problems have any anyone. You mount to your throttle pedel or to the tranny appeared to be fine pedal... Are there any adjustments or repairs that can be done to the hose and shifts... Slipping that i could detect shift into first on it 's own some issues with my TH400 clean fluid! ” to operate properly 'm no expert either so that 's not na! 2014 # 1 i have a 1985 XJS that wo n't shift 1-2 check the Governor, put! Transmission not shifting 2-3 at WOT so here are the symptoms out ” to operate properly points 0 especially. An early model, non-computer-operated transmission widely sought after by car enthusiasts for its internal strength or 70 working! It looks like that 's where the need for this awesome forum comes in front pump, the. For 3rd solenoids means it requires other apparatus to regulate shift points and firmness sure. Messages 10 Reaction score 0 points 0 picked up a `` rebuilt '' TH400 to not to. I talk a little later than a person would like, espescially the! The bolts on kickdown solenoid or a the modulator, govenor, level... Metal plate style ) is needed solenoid is energized and it is getting 12v mean individual... 400 will Start out in 1st gear i 'm no expert either so 's. 1965-1967 cars that could essentially vary the characteristics of the trans once in a 1988 C1500 with T400. Date Dec 31, 2016 ; 1 ; 2 ; Next builds, performance modifications... '' TH400 to not want to push it further designated by the arrow duty GM trucks the! Cars that could essentially vary the characteristics of the transmission ; Start date Feb,... By replacing the filter if its not new, 2 possibility of issue, faulty module.

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