68 with a th350 I've noticed it seems like it shifts from 1-2 too soon when I get at or near wot from a stop. It doesnt feel like it lets it build up rpm before it hits second. I dont drive the car much but its definitely something ive noticed this past year. It has the cable connected to the pedal since it was a swap from the original 68 2speed to the th350. Could it just be the cable adjustment? Or something else going on? I dont know much about transmissions btw. The car shifts great otherwise. Just feels like it has way more rpm left in it before it needs to hit second. Sent from my LG-H811 using Tapatalk
Can't believe no one has responded to this thread. You need to use a tachometer to see where it is shifting. Then modify the governor until it shifts where you want.
We like the way you reply Larry. :Brow: o No: :TU: I'm not much of a trans guy so at risk of giving the wrong info I didn't reply to this, but am watching because I would like to know as well. Derek
I forgot about the thread already haha. Tach is my next addition btw. But even without the tach it is definitely an early shift. Punch it from a 10-15mph roll and it still goes into 2nd too soon and takes its time. Manually drop it into 1st and the tire breaks loose and she goes. Ive also noticed that when putting it to the floor cruising in 3rd it takes a few seconds to finally downshift. No bog or anything, throttle mashed and it goes but the kickdown takes awhile to eventually kickdown. I've adjusted the cable at my foot by sliding the metal tang up and pushing the pedal to the floor to set it. Sent from my LG-H811 using Tapatalk
It's a very time consuming process to get the transmission to shift exactly where you want it. The governor, modulator, and detent cable all work together. One can affect the others. I am still trying to tweak my new transmission. The governor changes are the slowest process. The exhaust and ATF heat complicate adjustments because you have to wait for things to cool down. When you do the governor, change one weight or spring at a time, then evaluate. It's a slow process.
If you feel that you don't need a tach I have a good way of modifying your governor for best shift RPM. Select the lightest weights from the B&M kit and install them. Take car out on straight back road and floor it until engine blows(because you will never hit the rpm where the car will shift at). Rebuild engine. Install next heavier weight. Retest as above. If it blows rebuild engine and install the next heaviest until the engine doesn't blow or shifts. Keep going to heavier weights until the engine stops blowing. :grin: If you are serious get the tach and come back with real rpm numbers and not "early shift". I can't even believe I'm reading this stuff. ou: More seriously, a factory governor probably will shift around 45-4600 but with a cammed up 350 you should be shifting 5000+. If you are shifting below 5000 rpm you are leaving a whole bucket load of performance on table. Did I mention get the tach in there? Or you can borrow one and when you get the shift at a good rpm you can remove it. I believe the gov. from the ST300 is the same as the T350 which means you could modify the weights on that gov.(or add the B&M stuff to it) and you wouldn't have to modify the T350 governor. A possibility is the ST300 governor shifted at a higher rpm but that could be because of valving and pressures inside the ST300. What you could do is pull both governors and inspect them. The one with the smallest "small" weights will probably shift at a higher rpm and you could probably use that one for a bump in the rpm. If you go that way post good pictures of both governors and we could probably tell you which one will shift higher just by looking at the weights, assuming there is a difference.
Damnit my mobile app just deleted what I typed. Anyways i know i need a tach. Its coming soon. But ive driven this car for 22+yrs and can feel that Its definitely not staying in 1st veey long when I put it to the floor, just drops into second very soon and slugs along unless I manually throw it in 1st. Even from a 10mph roll it wont kick down. And wont downshift into 2nd for a good 3 seconds or so when cruising in 3rd. Its way late. Sometimes wont even downshift. I understand it may seem like im just guessing because i dont have a tach. But its not even close to that. It is definitely way too soon and I know its not kicking down into second like it should. Somwthings not right. Sorry but i can feel it. Its different i guess thats all i can say really. I'll just wait until the tach is in and post up real #s and go from there.
I understand you can feel the difference. Was this after the trans change? After the converter change? Or was this out of the blue?
No, definitely before the converter. The trans has been in here for some years now. Its hartd to say when It started but I'd say it was progressive over time. Its probablt been a year or so that I've noticed it. Occasional downshift missing with pedal to the floor etc. So naturally I assumed the kickdown cable and eventually tried to adjust it. It looks like its stretched for sure but assumed the adjustment would make up for that. Maybe the cable needs replaced? Before I try anything else maybe I'll try to run the trans really hot with very low fluid and slam it in and out of neutral, reverse and 1st while reving the motor up to 4500 with some wot throttle runs haha. That might adjust things Sent from my LG-H811 using Tapatalk
Pull the governor out and make sure the weights and springs are there, the valve in the stem moves freely, and nothing is gummed up and stuck. You really do need a tach to evaluate it further. No rush, I didn't see this thread until this morning and apparently, no one else did either:laugh: I can wait.
Matt, The vacuum modulator fail mode normally causes a delayed, higher rpm shift. Failure is ruptured diaphram, won't hold vacuum and can show as fluid in vac line nipple. The cables can and do stretch and fray, even break. You would likely have to remove it for a good inspection. As suggested, a thorough inspection of the governor is a good idea to see it all is in order and the shuttle piston is not sticking. SEARCH: th 350 cable, th 350 governor, etc for more threads on this issue. Also check the "similar threads" listed at the bottom of this thread.
Thanks guys. I'll read up some more on this. At least it gives me some direction. Yes my cable is stretched and frayed near the firewall hole. I just went out and looked at it. I'll be looking for another also. Sent from my LG-H811 using Tapatalk
Sounds like my th350 with the downshift cable not hooked up. Do this. Jack your car up and drop tranny pan, then drop valve body. Install a full manual body. Throw away downshift cable. And go have fun.:laugh:
It was many years ago when I twisted the input shaft on that st300 and swapped. But i do remember how fun that thing was when it kicked down getting on the freeway! Sometimes I wish I still had it Sent from my LG-H811 using Tapatalk
I had a healthy 455 in front of one of my ST300's back in the day. Couldn't kill it. I'm sure there's others here on the forums willing to practically give their ST300 away, should you be interested in scoring another one. :TU:
I broke a 300 on my trip to Alaska, with a 350 engine. It was replaced with a used TH400, it outlasted the car. Bruce Roe
Hey Bruce! been awhile. How have you been. Still tinkering with the early cadillac EFI systems? Sent from my LG-H811 using Tapatalk
I have a busted one in my garage too, broken from a sbb 300! A 2bbl yet! LOL To the fans of the SlushTurd300 :moonu: Derek
