1. No shift. (1 to 2, yes) 2 to 3, no. gets to 45 mph and engine, keeps roaring, no tranny change. 2. Barely no reverse, put in reverse, slowly starts going backwards but barely with any speed, press gas and engine roars but with no reverse speed increase. Car actually jerks in reverse, with slow to no response. With all that it's doing car takes off with great response. but with no high gear, shift ? Any suggestions or ideals, and does any one have the TH400 repair on-line manual they can send me ? Help...
I am not a transmission expert, but I think you have internal parts failure-wear. the fact you get a 1-2 shift, makes me belive the vacuum modulator hose is connected. sounds like a rebuild is in order. Maby a transmission pro can chime in to better help.
I had this problem before in my truck, turns out the transmission needed to be flushed and have the transmission filter changed. The mechanic told me a clogged trans filter can cause a lot of problems on a transmission. I would flush the trans and change the filter first. Worth a shot.
The later model GM service manuals have a chart of what components are applied in what gear that can be helpful in diagnosing these things. My '70 service manual has something similar, but it is in picture form. The charts are something like: Gear.........................................Component .....................FwdCl...DirCl..FrtBand..IntCl..IntSprag..RollerCl...RearBand...... Rev..................Off......On......Off......Off.....Ineff.......Ineff........On L1....................On......Off......Off......Off.....Ineff.......Effective..On L2....................On......Off......On.......On.....Effective..Ineff.......Off D low gear.........On......Off......Off......Off.....Ineff........Effective..Off D 2nd gear.........On......Off......Off......On.....Effective...Ineff......Off D 3rd gear.........On.......On......Off......On.....Ineff........Off.........Off Using a chart like this tells us that only the direct clutches are used for both reverse and D, third gear. These clutches are most likely burnt, or not applying, if all other causes for a no 2-3 shift, soft reverse have been eliminated.
Just my humble opinion, but "do not pass Go", change master cylinder. This is a safety issue. Worry about shifting after you can safely stop. Voice of experience from a guy who went sailing through a red light once with foot on floorboard pressed hard against brake pedal....
Sounds like a problem in the direct/reverse clutch drum. The reverse band is not on when in third gear. Possibly worn clutch plates which is usually caused by the rubber lip seals on the piston being hard from age or torn, and also could have worn or broken seal rings on the center support which the direct drum rides on, or grooves in the drum from the seal rings. Filters usually clog up due to parts in the trans failing.
Well after some further investigation of my Tranny, replaced governor/seal again, and just looking around, decided to take car up to Amocco, and wow !! After 15 minutes, i left there with a $1400.oo estimate. Car never went into garage or anything,told me they suggest a rebuild and that was the price of it. Car will be sitting for awhile !
If you are looking to go with a full rebuild and don't feel like tearing into it yourself, check with your local club for what trans guy they use. Out here, our local Th400 guru completely rebuild mine, including removal from the car, a new shift kit, heavy duty sprag, etc. for a few hundred less than that quote you received. Best of luck.
Okay guys, help me out here, but just a thought. With all the issues i'm haveing now, withthe Tranny not changing into high gear and now noticeing at red lights that my brake pedal is slowly going to the floor. Could my Brake booster be causeing my issues ? (I'm guessing) but with my booster looseing vaccum, that my tranny is not getting enough vaccum it requires to shift gears ? whatta ya'll think ?
not a chance. two seperate issues. lack of vacuum would make for a hard brake pedal not one that slowly goes to the floor.
Ok guys i'm back again. Got my hands on another TH400, this weekend. Supposedly from the old owner,"works great, never an issue". but figured while tranny is on rear of truck, now be a good time for a new filter/pan gasket, kickdown switch and module. But what i'm haveing a few thoughts of, "should i go with another torque convertor" ? Currently useing stock, 455/400 tranny convertor. no major engine mods, besides B4B intake,holley carb, and long tube headers. Is it worth it, and will i see a performance increase, or is it wasteing money ? No track raceing or anything like it, just a big block cruiser..
A lot of us like and use this one" http://www.v8buick.com/showthread.php?t=147066&highlight=9.5+convertor+jw
With a stock engine, there is no need to go with a different converter. If it had a cam that bumped up the power range, yes.
"damn, daMN, DAMNNNNNNNNNNNNNNNN", not again !!!! Took car out Sunday for some early morning coffee and a few yard sales/flea market shopping. Car running great, stop at corner store for paper, and now no, "Drive"!!! Got 1 and 2, but go into drive, and nothing, any suggestions ?
That is a different trans? If the other stuff mentioned is done, it could be low fluid level. Bruce Roe
Naw, this is Trans (2), replaced first one and now after a few months,now haveing issues with the replacement. Off Wednesday, did a filter and gasket replacement, new fluid.while under car notice that the plug, on the driver side of the trans, going to the kickdown solenoid, had broke off and wire was just hanging down. Replace plug, Reconnected plug/wire, fill with fluid and and still nothing..
