So after going on record as defending the ST300 so many times, I managed to blow mine up this morning.... Was on my way to work, and it wouldnt downshift like it normally does but it was running great. I got on the highway and went to change lanes in the tunnel in downtown Hartford - stepped on the gas (hard, but didnt floor it) and ... well, there really wasn't any noise at all.... All the fluid dropped out of the tranny - hit the exhaust and caused a HUGE cloud of smoke....immediately I had no gears and the revs climbed, but slowly as the rest of the fluid pumped out.. coasted out of the tunnel and like magic there was a breakdown lane. Drifted in until it woudnt roll any more and listened - iding like a kitten! Went to put it in park, and the shifter is jammed. stuck in drive. Shut it off, looked under the car, smoke all pouring out and the underside of the car is coated -exhaust, rear axle, etc..there was a thin trail leading out of the tunnel but it only leaked about a 6" puddle where it landed. Hopped over the guardrail, tow truck came, got it up on the flatbed and visually checked it all out, expected to see parts hanging out. But everything looked intact! All covers, pans, the case sides, tailshaft, etc.. all looked fine but covered in fluid... Tow truck gave me a ride to work and the car is at the trans shop - maybe I'll get to see what happened tomorrow if they can get it in the air...I know something catastrophic happened, you cant dump that much fluid that quick without a BIG hole...and the shift being jammed isnt a good sign... there has to be chunks of something in there! So maybe this is my big chance to swap the ST400 into it! I doubt there's much left of the ST300. More to come....glad at least I didnt grease the track!
Ouch Rhett! If it makes you feel any better, I had a torque converter bolt come loose yesterday, bounce around inside the inspection cover, and cause all sorts of havoc. Funny thing is, I can't find the bolt anywhere... ou:
Now that's a good trans, failing and still letting you get to a turn out! My OE TH200 behind the 231 wasn't so kind to my Dad, lol. He was driving my car to work (my daily driver at the time was a '69 Firebird) when out of the blue the rear end locked up solid and he came to a skidding halt from 35mph, right in front of the police station, lol :laugh: Luckily it was 5 am and no other cars around. After messing with the shifter he got it into a gear and managed to make it the half mile home. We pulled the trans and brought it to the trans guy at my work (a Pontiac dealership) where the parts were more scooped out than anything else. Amazed me he even had a gear to get home. I put a junkyard 2004r in the car as a replacement, best thing to ever happen to that V6.
Early Carnage Photos! I still have to bring the pan down yet, but but the casting that held the Low Servo Cover retaining ring is literally blown off the case - It's toast! And thats not even talking into account the shifter wont move...there's more going on in there. How does that happen? If someone said I'll give you a million bucks to blow the servo out of the side of the case (while just driving down the highway!), I wouldnt have a clue how to do it! So now I have to decide.. get another case and salvage the guts of mine or swap the ST400 into it...
Rhett,I have a sp300 you van have for $100.00 ,without the torque converter.Bruno. ---------- Post added at 07:24 PM ---------- Previous post was at 07:23 PM ---------- It has to be rebuilt.Bruno.
Bruno - thats a great offer.. I may take you up on that. That would keep me stock, which is what I'm really trying to do...what's it out of?
Bigpig, I thought you had a pretty cool goal with the stock drags this year. Stick with the 300 for the season and do what you planned, always next year to start trying to get more out of the drive train:TU:...of course opions are like a$$ holes, everyone has one that's just my opionuzzled:
or swap the ST400 into it... No Contest from MHO Ive been playing with my 67 340; had pretty good ST300 in it, tried a Jim Weise convertor, but when I swapped in a t350 my 340 felt like it got turbo boost.
Ted - I'm with you - ultimately the 400 goes in, it's my favorite trans of all. I already have the tranny, 67 shifter, linkage and console indicator - just need the crossmember, rod "pass through" plate and yoke. (if anybody has a lead on these, please let me know) - I believe the 66 ST400 has a pretty specific yoke too - large shaft, same spline count but smaller OD than later models.. Does that sound right? But to 66GSConv's point, I never got to pull it all together and race the PSMCD out in Michigan. I could probably pull it off, they might not pick up that the TH400 is in there or maybe I could get by with a wink and a nod (not being a front runner), but somehow it wouldnt be right... I'm leaning toward building the ST300 and running that one until I've done all that. Depends on how salvageable the GS specific stuff out of my tranny is (Converter, valve body, foward and reverse clutch assemblies, stuff like that. I'm gonna pull the pan down this weekend and see how screwed up everything is - I expect carnage..... I think it's worth noting this may have been related to a longstanding issue with the case..The pan was always wet below that cover, no matter how many times I resealed it, and that goes back to when I bought the car in 2008 (?) That doesnt explain why something is now blocking the sector shaft though......
Took the pan down - more mystery..... Everything looks good except the front pump pressure valve came down and was blocking the sector gear. The c-clip is no where to be found (I havent checked the filter yet. The groove in the case that holds the c-clip seems to be intact..but no broken pieces, etc..fluid smelled a little funky, but not really burned and was still pink....and of course the low servo is totally blown out... What the hell happened? I'm leaning toward pressure build up, but you'd think that would balloon the converter and wipe the motor out first... I guess the good news is all the GS specific internals are still good. So there's something. And I've still got the build date specific servo cover. Were the 65 trans cases stamped with VIN's? I read somewhere that they didnt do that on GTO's until 68 or so..
I had to put a huge piece of cardboard under the car so it wouldnt drip tranny fluid on the Pontiac while it's on the lift - I mean the bottom is just PAINTED! I'm gonna have to steam clean it, it's still dripping from everywhere.
Looks like I found a potential core out of PA..so I'll probably stick with the ST300 rebuild although Ken from Everyday Performance generously donated a short shaft TH400 to convert my ST400 to a normal talshaft yoke size.
I love the THM 400 too, but it seems that you race your car. The THM 400 will absorb more horsepower then either the 300 or a THM 350. If I were serious about racing, I would build (or have built) a really strong smaller gearbox rather then use a 400. If what you want is brute strength, then the 400 is your box.
John - You're absolutely right - and if I could build a switch pitch 350, thats what I'd do - even still a good perf build 350 with an adapter plate is probably the right way to go - I just love the switch pitch though, and at some point this car will get retired from racing. When that happens, the 400 will make more sense. As far as racing goes, I'm only serious about the pure stock aspect, and that keeps me in the ST300 whether I like it or not - If I build a non-stock car, it'll probably be my 71 clone, and thats in the "five year" plan.....
what would realllllllly put the power to the ground would be a clutch/th 400.....:idea2: like was in the first funny cars.....:laugh: back when they were A/F/X class.....
Up to my elbows in the grease - first the 65 goes down, then the Pertronix module in the 73 craps out (and then I find the distributor is eating itself alive) and then today the Pontiac brake pedal goes to the floor, and then while limping it home the float sinks to the bottom and douses the whole top of a very hot engine. No fire, thankfully. I'm thinking of going to get the 71 and see if I can go 4 for 4. Hope your week is going better than mine......
