mymontesa70 Posted July 18, 2010 Share Posted July 18, 2010 any tranny techs in here?....scratch that i know all of you are well heres my current dilemma.. for starters i have a 350 sb with a turbo 3 trans . i also have a b&m mega shifter which will come into play later. so, if the car is in drive and im just crusing not even putting the pedal down the car will wind up to 4 grand! before it shifts ...scary....this is the case no matter what , getting on the highway ,cruising, it does it full throttle to but that's what its always done and should do as far as im concerned now the only way ive found to remedy this problem is if i manually bring it through the gears , if i blip the throttle and then shift i can get it to go through the gears at whatever rpm range i want when im cruising , kind of like clutch less shifting. so to wrap things up im a total amateur when it comes to trannys and have no idea whats going on ...any advice? as always any and all help is appreciated , i love this place Quote Link to comment Share on other sites More sharing options...
TN454Monte Posted July 18, 2010 Share Posted July 18, 2010 What Allan asked about the fluid and filter. A clogged filter or burned/weak fluid in a Turbo Hydramatic trans can wreck all sorts of havoc.... Quote Link to comment Share on other sites More sharing options...
Ian Posted July 18, 2010 Share Posted July 18, 2010 Have you checked the fluid level after it is warmed up on level ground? Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted July 18, 2010 Share Posted July 18, 2010 first!!!! check the vacuum line to the trans!!!!! Quote Link to comment Share on other sites More sharing options...
stangeba Posted July 19, 2010 Share Posted July 19, 2010 What has changed? I would also look for the vacuum line off the trans or intake. Could the kick down cable be stuck or has fallen off? Have you changed anything, moved anything? Even something a simple as a different air cleaner assembly could cause the trans vacuum line to be knocked off or pinched. Good luck! Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted July 19, 2010 Share Posted July 19, 2010 I agree with Sam. If there is a vacuum leak to the modulator the modulator is telling the trans that the carb is a wide open throttle Quote Link to comment Share on other sites More sharing options...
CrazyDavey Posted July 19, 2010 Share Posted July 19, 2010 I agree with Sam. If there is a vacuum leak to the modulator the modulator is telling the trans that the carb is a wide open throttle x3 Quote Link to comment Share on other sites More sharing options...
mymontesa70 Posted July 19, 2010 Author Share Posted July 19, 2010 well embarrassing as this is , and im sure there is going to be some finger waving.....i have never changed the tranny fluid or filter:( i bought when i was 18 so thats...7 years! i guess thats next on list also cant the modulator itself just go bad? i could be way off. thanks for all your help fellas ill keep you posted but expect it to be a while. im having motor issues currentley and lets just say the day has been frustrating. im sure ill post something to you gurus later asking for help. by the way the tranny is the one thing ive really neglected on my car and now im paying for it. Quote Link to comment Share on other sites More sharing options...
CrazyDavey Posted July 19, 2010 Share Posted July 19, 2010 never hurts to do a little preventive service work Brandon, some fresh fluid and a filter is a good idea. I would still check out any potential vacuum issues with the connection to the modulator. Yes they can fail but usually it is accompanied with a lot of smoke out of the exhaust because the trans fluid will go directly into the intake system....Dave Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted July 19, 2010 Share Posted July 19, 2010 always check the easiest first, it's usually the problem Quote Link to comment Share on other sites More sharing options...
7tonemonte Posted July 19, 2010 Share Posted July 19, 2010 always check the easiest first, it's usually the problem Aint that the truth! I pulled the tranny from my 69 Olds many years back due to it not shifting only to find out the detent cable was hung up under the hood not connected! Which reminds me, the Monte's cable is not connected to the carb also Quote Link to comment Share on other sites More sharing options...
kc8oye Posted July 19, 2010 Share Posted July 19, 2010 my TH350 used to do that.. turned out the diapgrahm in the vacuum modulator had ruptured... if you have a hand-held vacuum pump, put about 15" of vacuum on the modulator (don't use much more, or you will rupture it) and make sure it will hold that vac.. and also make sure the valve inside the modulator actully moves back and forth.. don't fret.. a new adjustable modulator is only about $11 or so. I got the adjustable one. .turned the screw all the way in. .backed it out about 2 turns and put it in... it would bark the tires no problem going into 2nd Quote Link to comment Share on other sites More sharing options...
mymontesa70 Posted July 19, 2010 Author Share Posted July 19, 2010 im positive all my vacuums are fine so lets hope it fluid and filter or the modulator...ill let you know ,thanks again everyone Quote Link to comment Share on other sites More sharing options...
mymontesa70 Posted July 20, 2010 Author Share Posted July 20, 2010 hey Tim just curious did you get just a generic adjustable summit or jegs brand modulator or did you go with the b&m or something with a name on it? Quote Link to comment Share on other sites More sharing options...
kc8oye Posted July 21, 2010 Share Posted July 21, 2010 i bought a generic one from my local auto parts store (it was one of those rare moments I actully bought something at autozone) Quote Link to comment Share on other sites More sharing options...
kc8oye Posted July 21, 2010 Share Posted July 21, 2010 my th350 would only downshift occasionaly when I nailed it (Even with the kickdown cable connected, and adjusted) I got used to just standing on it and letting the engine lug along in 3rd gear with my 2.73's.. one day it decided to downshift just for the heck of it.. left me climbing the freeway on ramp in a wild fishtail (naturally I wouldn't take my foot off the gas LOL) Quote Link to comment Share on other sites More sharing options...
mymontesa70 Posted August 13, 2010 Author Share Posted August 13, 2010 just thought id give an update i went and bought a 10 modulator from napa and now shes shifting tip top ,couldnt be happier. though i dont know how long that thing will last for 10 bucks but at least its an easy swap thanks again for the troubleshooting help. Quote Link to comment Share on other sites More sharing options...
kc8oye Posted August 13, 2010 Share Posted August 13, 2010 You know I gotta do it.... TOLD YA SO!! lol j/k Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.