When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Top of first gear, 6200 RPM, shift to 2nd and BANG.....then a transmission full of neutrals.
Just happened yesterday and I haven't taken a look other than to see that the flexplate and torque converter are still connected to the engine and rotating at engine speed. When the engine is shut off, you can hear some component spinning and coasting to stop. Not sure if it's inside the converter or the pump.
My question is: What's the most likely point of failure?
For the record, upgrades are: TCI converter, .500" boost valve, "Corvette" servo, Trans Go shift kit (with new separator plate), (a few other mods that escape me at the moment). This transmission had been on the rebuilder's bench a couple of times. Last time through (after the sprag let go), improved clutches were installed but no other hard parts. That was tens of thousands of miles ago with no trouble whatsoever. It seems the new heads and cam put it over the top. That lasted 2000 miles.
I'm just interested in others best guesses. A new transmission is likely to be on order soon.
That's the plan. I somehow doubt cheap though but that remains to be seen.
This thread is more about the fun of speculating about what happened more than anything else.
Whatever the outcome, I think it's time to step it up a little anyway. That this transmission lasted as long as it did is a marvel really. I thrashed on that thing mercilessly for years. Even towed a 12' U-Haul trailer for 2500 miles with the lock-up non-functional and it still took a beating for another several thousand miles.
Thanks for the condolences red.
I'm with you on that one.
It'll be a while before I get around to yarding the trans out. In the meantime, I've started the shopping process.
Like my hot rodding friend says, "It's always something!"
Where the description of the failure included the infamous "BANG !" , my guess is the "sun gear reaction shell" went and became little fragments of "former sun gear reaction shell"
Damn, sorry to hear this Skinny, I just went through this two weeks ago on my 700r4; my case busted at the pump housing. Not sure what failed internally yet, as I haven't torn it down to see, but I just got back on the road with a level three Raptor 700 from PATC and I'm very happy with it so far. It seems to be putting much more power to the wheels than it was with the stock transmission.
they make a billet pump $200 (TCI) picked up mine with other parts..
or ya can have a stock one cryo Treated to help out..(about $20) to treat.
billet 10 vain is center of pic..
Last edited by articwhiteZ; 11-06-2016 at 12:10 AM.
all the best hard parts today come to over $3200 (converter was $700 of that..) but that's with a trans brake as well.. not cheap..
the 700R4 takes money to make it live. in the HP world.. it would be cheaper to go with a th400and add a overdrive...
Last edited by articwhiteZ; 11-06-2016 at 11:48 AM.
Part of the decision making process will be determining how much transmission I'll need. At a max torque output of 450 ft/lbs, I'm thinking I'll need less than the latest and greatest parts. While a 5-gear planetary would be nice, it's doubtful to be an essential component for this build. Something like a billet pump (like the TCI unit mentioned above) makes sense though seeing as this is probably what's grenaded on mine.
The other decision is whether to use my trusted transmission builder and let him have at it or go with something already built like a TCI or PACT.
i have a PACT th350 that i bougt 11-12 years ago. it served me well for 10 years. my only complaint was a mystery leak i could'nt find for years. they forgot to put the square cut o-ring in the tailhousing,..duhho. then last year i broke 2 pumps and ate an input shaft. i also found they used transmission RTV instead of a seal on the governor cover, but it never leaked. overall, can't complain.
Now that my engine is done, I am in your same boat Skinny. I have a 700r4 and need to decide what I want to do.... To it or another... Also need to figure out what stall... I also have all winter.
Well unless that 700 of yours is beefed up more than mine, you know it's gonna pop with that torque number you just laid down. My guess is that the improvement over my last build at the shift point is likely in excess of 60 ft/lbs. Enough of a gain to put it over the edge. And certainly less than yours given the difference in cubes.
I was just in touch with a transmission builder back home. Excellent rep.
I'm going to check out the likes of PACT, Gearstar, TCI and the rest and find out what's done regarding upgrades for a given power level. See if my guy can compare.
What I've remembered from looking at transmissions before this event was that any aftermarket remanufacturer will include their own converter. It'll be tough to get a properly stalled unit for my specific application through one of those guys.
I remember those pictures.
I think your bang was much louder than mine!
What failed exactly (besides what appears to be everything)?
And what was in front of it?
Not 100% sure what started the failure because its still on a shelf. If I unbolt the pan she will fall apart. Been thinking it may be this winters project.
Just a old "slightly" modded 350 tpi.
TTOP350, Holly crap. That had to of been a bang!! reminds me of the goat on street outlaws. LOL
Skinny, I def want a tran that is capable of 600hp/torque. I like to have a safety factor of some sort. Wonder if we can find a place that will give us a deal? 2 trannys for x amount off or what have you. Not to go the cheap route at all.... Just thinking ya know....
I am leaning towards a kit tho... I think I am capable of building one.... Only thing is, I dont have the experience/knowledge of what to look for, mods, etc. I can def spot a bad. worn part but it takes years to get good at this stuff as you are well aware of.
they make a billet pump $200 (TCI) picked up mine with other parts..
or ya can have a stock one cryo Treated to help out..(about $20) to treat.
billet 10 vain is center of pic..
So what is the large piece to the right of the pump?
TTOP350, Holly crap. That had to of been a bang!! reminds me of the goat on street outlaws. LOL
Skinny, I def want a tran that is capable of 600hp/torque. I like to have a safety factor of some sort. Wonder if we can find a place that will give us a deal? 2 trannys for x amount off or what have you. Not to go the cheap route at all.... Just thinking ya know....
I am leaning towards a kit tho... I think I am capable of building one.... Only thing is, I dont have the experience/knowledge of what to look for, mods, etc. I can def spot a bad. worn part but it takes years to get good at this stuff as you are well aware of.
I wouldn't attempt this myself despite having rebuilt an automatic before. There are just too many nuances to educate myself on. And a failure is not something I'm interested in dealing with.
My racing buddy back home has a builder with a good reputation. Punctual and economical too. I can custom design what I'd like to have and go from his feedback. That's the route I figure I'll go.
My other consideration is the lousy Canadian dollar. I'll get creamed on the exchange rate and shipping wouldn't be cheap either. I have U.S. trip planned over the holidays so I could always pick-up which is what I intend to do with my converter. But still, taking a 35% hit on the dollar on a 2500$ purchase is a considerable chunk of change.
Funny you should mention the package deal. One of those web pages I linked to has a 50$ off sale if you purchase two.
Dana at Pro Built Automatics is on this site often. Seems a decent guy and one that you could talk with and work out your own blend of slushbox goodness.
Where the description of the failure included the infamous "BANG !" , my guess is the "sun gear reaction shell" went and became little fragments of "former sun gear reaction shell"
Originally Posted by The Project
Maybe time to install a "beast" as part of the rebuild.
Originally Posted by TTOP350
Mine went bang a few yrs ago as well.
Yep I remember those pictures too . The caged looking thing hanging out of where the transmission's outer case is torn apart is the infamous Sun Gear reaction Shell , best replaced with "the Beast" as the project said during any high performance rebuild . Seeing and remembering TTOP350's photos reinforces my guess that skinny z's bang originated right there in the same spot , just maybe not quite as violently as TTOP350's did , good grief that looks like when the baby alien ripped outta the dude's chest in the Alien movie !
I may have the transmission out by days end tomorrow. How far I'll get into will depend.
As far a replacement, I've contacted a builder and we're going to discuss the process and parts sometime this week.
In no particular order it seems upgrades should include:
A better (billet?) pump.
Sun shell. Either a "Beast" or the Sonnax unit (which I hear is better).
5 gear planetary(s). Not sure about that one.
Beefed up input drum.
The usual assortment of bigger and better servos, clutches and steels.
And other items too numerous to mention. Some I've got in this transmission already.
Best estimates are torque and horsepower are about 450 apiece. I'll have to trust my builders experience regarding how far to go with the improvements.
So what is the large piece to the right of the pump?
One of the planetary gear sets. Something else that can be upgraded. The 5-pinion planetary is generally in the "stage 4 or 5" category (upwards of 650 ft/lbs).
What I've remembered from looking at transmissions before this event was that any aftermarket remanufacturer will include their own converter. It'll be tough to get a properly stalled unit for my specific application through one of those guys.
PATC will build you a converter for your car based on your dyno sheet, curb weight, gears and tire height; I had them build a 2600 stall for mine with out the lock up.
PATC will build you a converter for your car based on your dyno sheet, curb weight, gears and tire height; I had them build a 2600 stall for mine with out the lock up.
I saw that on their website. I didn't know PATC made converters.
My question is: What's the most likely point of failure?
Pan was clean and free of debris.
The pump is OK.
So is the sun reaction shell.
The input planetary looks good (in that all of the teeth are present and accounted for). I haven't been deep into the case to see if the reaction planetary is smoked or not.
But the splines in the torque converter turbine have seen better days. I can't say for certain at this point but it seems the engagement between the turbine and the input shaft is toast. That would explain the no gears in any position. And also the "gear whine" I heard when the engine was shut off but something was still rotating and coasting to a stop. Not sure if the splines being suddenly cleaved off would cause that significant bang though.
The presence of small metal splinters pulled from inside the pump and the converter, although not many, are a good indicator that the splines are stripped too. I would imagine that the bulk of the material is jammed inside the converter housing.
At any rate, it's time for a rebuild. The 2-4 band assembly looks crispy and the drum itself is scored. I imagine the clutches and steels are in much the same condition. Plenty of hard miles and countless red line shifts too.
That's the way it goes.
Thank You for the info skinny z , so it was the torque converter it sounds like . Funny I was so focused on the sun gear shell mostly because of remembering the pictures that TTOP350 had posted some time ago and thinking of the bang it musta made when that let go . Well , that , and the fact that of all the transmission's internals , if the sun shell is THAT notoriously weak as to have an aftermarket replacement named "The Beast" being marketed to replace it , I figured the factory part shattering was a fair to likely bet .
It's great that it sounds like you've got your plan all mapped out for what comes next for fixing it .
I'm actually surfing for what the big rebuilders are doing for upgrades at this very moment. Seems any aftermarket performance orientated 700 gets the "Beast" sun shell or equivalent. The likes of Gearstar, PATC and Monster do anyway. They've probably seen TTOPS pictures too.
The dividing line between something that will handle 450 tq and those approaching 600 tq is interesting. Everything before is pretty standard. After 600 almost everything is replaced. At almost double the cost. In between is kind of blurry and it's sort of where I stand.
It comes do making a choice as always. This little engine optimistically makes 425 ft lbs of torque. Of course you don't just to satisy your current limit. It's always good to have some degree of extra engineering built. That said, I don't see any plans for too much more going forward unless of course I spit out the crankshaft next season. Though, if that happens, I'll move on to the junkyard LS bandwagon and go with that. Then the transmission is replaced again.
Thanks for your input.
More to come.
So what is the large piece to the right of the pump?
the big part to the right.. is a input drum with a bolt on retaining face. No snap ring it also has a billet input shaft. and takes more clutches and steels.
a 5 pinon rear planet is above the billet pump. and a 6 pinon planet is at the 11 o clock from the pump gear.. making the 700r4 a close ratio..
more like a th350/th400 when shifting into 2nd and 3rd...and a better then the beast sunshell. can also be seen....
Last edited by articwhiteZ; 11-10-2016 at 09:56 PM.
That's a mighty fine selection.
I'll end up with half of those upgrades. The 5 gear planetaries are on the edge of my torque requirements (both for now and the foreseeable future). Haven't fully decided yet (certainly not the 6 pinion).The hardened input shaft and beefed up drum are beyond my needs but certainly the way to go to build it to the nth degree. Is that a Beast sun shell or the upgraded Sonnax part? Billet pump?
Glad it wasn't me. It must have been absolutely deafening when it happened.
I'm sure my "bang" was considerably more subtle. Just enough to shear off 30 splines in the converter.
Top of first gear, 6200 RPM, shift to 2nd and BANG.....then a transmission full of neutrals.
Just happened yesterday and I haven't taken a look other than to see that the flexplate and torque converter are still connected to the engine and rotating at engine speed. When the engine is shut off, you can hear some component spinning and coasting to stop. Not sure if it's inside the converter or the pump.
My question is: What's the most likely point of failure?
For the record, upgrades are: TCI converter, .500" boost valve, "Corvette" servo, Trans Go shift kit (with new separator plate), (a few other mods that escape me at the moment). This transmission had been on the rebuilder's bench a couple of times. Last time through (after the sprag let go), improved clutches were installed but no other hard parts. That was tens of thousands of miles ago with no trouble whatsoever. It seems the new heads and cam put it over the top. That lasted 2000 miles.
I'm just interested in others best guesses. A new transmission is likely to be on order soon.
Never had mush success with a 700r4. Both of the last two that I roached went away initially by the converter not locking up into O.D. on the highway after having moved or pulling something using reverse. You might look into a local place here in Akron Ohio named Janis transmission. The owner, Vince, specializes in insane strong 200r4's for boat-anchor 3.8's in Grand Nationals. Dont know if you are privvy to a 200 or not but its my $.02.
Never had mush success with a 700r4. Both of the last two that I roached went away initially by the converter not locking up into O.D. on the highway after having moved or pulling something using reverse. You might look into a local place here in Akron Ohio named Janis transmission. The owner, Vince, specializes in insane strong 200r4's for boat-anchor 3.8's in Grand Nationals. Dont know if you are privvy to a 200 or not but its my $.02.
Sorry for the lack of an introduction everyone but whatup? Hello from Akron Ohio- 1st time post. Found this board pokin around cuz of my 3951511 400 that is unmolested and still has cross hatch marks in the original bores. So I was just wondering how no one mentioned that some of them were rated at FOUR hundred ft/lbs of torque? And, whats the deal with NO 4 valve heads being available for our 4.400" bore spaced s.b. engines?
I have never had good luck with the 700R4's either, I put one behind a mild 355 in a 77 Monte Carlo, lived there for about 2000 miles after rebuild, blew the planetary gears, My stepfather has an 84 Vette, with an all original 350 CFI, which was rated at like 205hp I think, it blew out the planetary gears as well around 100k miles. Now I have talked to several transmission builders and they all said about the same thing "Yeah I love the 700R4, every time I see a 90's truck pull in to my shop, I know my bank account is about to get bigger, very easy money in those transmissions." I love the 200-4R's, they are a much better design and can handle more power, also are shorter, the same length as a TH400, better gear ratios, I hated the large RPM drop between 1st and 2nd with the 700's. The 200 also has a better overdrive gear, .68 vs .7. I had an 87 Monte Carlo SS and the 200 was very very responsive in it after a trans cooler and a shift kit. Also when I swapped the TH350 to a 700R4 into my 77 Monte Carlo with the 355, my car ran about .5-.7 seconds slower in the 1/8 mile.
Never had mush success with a 700r4. Both of the last two that I roached went away initially by the converter not locking up into O.D. on the highway after having moved or pulling something using reverse. You might look into a local place here in Akron Ohio named Janis transmission. The owner, Vince, specializes in insane strong 200r4's for boat-anchor 3.8's in Grand Nationals. Dont know if you are privvy to a 200 or not but its my $.02.
At my power levels a built 700 should last with little trouble provided the right parts are installed.
Funny you should mention your converter not locking up. I had towed a trailer across the country with my lock-up non-functional. Engine temps where about 240 for 10 hours a day over the 4 day trip. Transmission temps I expect where also on the high side. I ran a TCI 10" converter and without the lockup, the engine was never less than 3000 RPM. Thing is, that transmission survived to go through another 5 years of drag racing and street abuse. The engine lost a rod bearing eventually but the 700 hung in there.
As for rebuilding, part of my problem is the terrible exchange rate between the Canadian and U.S. dollar. Anything I buy in the States has about a 40% premium attached to it. Then there's shipping. For a big ticket item like a transmission, I want to keep it local. Fortunately, I have a rebuilder with a solid rep. I assemble the recipe of parts and he puts it all together.
At least I hope that's how it goes.
Sorry for the lack of an introduction everyone but whatup? Hello from Akron Ohio- 1st time post. Found this board pokin around cuz of my 3951511 400 that is unmolested and still has cross hatch marks in the original bores. So I was just wondering how no one mentioned that some of them were rated at FOUR hundred ft/lbs of torque? And, whats the deal with NO 4 valve heads being available for our 4.400" bore spaced s.b. engines?
By the way, I completely neglected to say, "welcome to 3rd Gen". It's always good to meet a new member.
Back to your topic, an excellent couple of questions however that's something that's better suited in the Tech/General Engine section.
I'm sure you'll get a few opinions on that.
I for one am a former owner of an all original 400 CID SBC. Wish today that I still had it.
I have never had good luck with the 700R4's either, I put one behind a mild 355 in a 77 Monte Carlo, lived there for about 2000 miles after rebuild, blew the planetary gears, My stepfather has an 84 Vette, with an all original 350 CFI, which was rated at like 205hp I think, it blew out the planetary gears as well around 100k miles. Now I have talked to several transmission builders and they all said about the same thing "Yeah I love the 700R4, every time I see a 90's truck pull in to my shop, I know my bank account is about to get bigger, very easy money in those transmissions." I love the 200-4R's, they are a much better design and can handle more power, also are shorter, the same length as a TH400, better gear ratios, I hated the large RPM drop between 1st and 2nd with the 700's. The 200 also has a better overdrive gear, .68 vs .7. I had an 87 Monte Carlo SS and the 200 was very very responsive in it after a trans cooler and a shift kit. Also when I swapped the TH350 to a 700R4 into my 77 Monte Carlo with the 355, my car ran about .5-.7 seconds slower in the 1/8 mile.
I'm familiar with the shortcomings of the 700 but the aftermarket has really stepped up. Especially in the last few years. 5 gear planetaries are the norm (and a direct swap from a 4L65E as I understand it). Loads of upgrades, mostly ones that can be directly swapped from the later and much improved models.
I also familiar with the 200 and it's reputation. To tell you the truth, I've seen those blow up as well. It's all in the rebuilder and the parts selected. Not to mention what's installed in front of it. Problem with the 200 for me is it's size. These 3rd gens always require some kind a custom y-pipe to connect the headers to the balance of the exhaust (unless you're running a couple of mufflers dumped under the car). In my case, the y-pipe and transmission cross member are modified to suit the 700. Swapping to a 200 means building a new exhaust and cross member. More work than I care to take on right now.
As for the gear ratios, what we've found, is that with the right converter, the gear split isn't noticeable. The Monte Carlo, which has basically the same spec of engine, transmission and rear gear as the Camaro has a Yank PT4000. Flash stall is about 4000 and RPMs never drop below 5000 on a drag racing pass. You don't see the RPM drop nor the associated lack of acceleration.
Top of first gear, 6200 RPM, shift to 2nd and BANG.....then a transmission full of neutrals.
Just happened yesterday and I haven't taken a look other than to see that the flexplate and torque converter are still connected to the engine and rotating at engine speed. When the engine is shut off, you can hear some component spinning and coasting to stop. Not sure if it's inside the converter or the pump.
My question is: What's the most likely point of failure?
For the record, upgrades are: TCI converter, .500" boost valve, "Corvette" servo, Trans Go shift kit (with new separator plate), (a few other mods that escape me at the moment). This transmission had been on the rebuilder's bench a couple of times. Last time through (after the sprag let go), improved clutches were installed but no other hard parts. That was tens of thousands of miles ago with no trouble whatsoever. It seems the new heads and cam put it over the top. That lasted 2000 miles.
I'm just interested in others best guesses. A new transmission is likely to be on order soon.
I had this happen.
If all gears are neutral, its probably the pump that exploded.
have you taken the pump apart Skinny? just curious what it looked like inside.
i have a buddy that his tranns guy recommended the 200 over the 700 for his big block. but i understand your reason for wanting to stay with the 700. theres a local guy here that refurbishes and sells school buses. he uses 700s in all of them, so i guess they must be capable of moving a lot of weight. i've personally never had good luck with them myself.
it just depends on who is putting them together.. Lingenfelters did my 700R4... car was running 11.s in the 90's.. that tranny is a none lock up 3300 stall manual/auto.
iv seen a lot of hoopla from others...but none would hold up to what mine has.. now just the hard parts upgrade is over $3000.. not cheap.. ya get what ya pay for....and a lot of shops will not use all the good parts..as they want to put money in there pockets.. and cheap a$$ junk in a tranny to get it out the door..sorry its true!
somebody tells you they are going to make you a tranny to hold up to 600 hp. and not install a billet input shaft. and smart drum..they are taking you for a ride...lol.. (that set of parts runs $600 by them selves)
the 700R4 can be made to take a beating..mine is still 100%.. just doing a 2nd one with all of the aftermarket parts made today..
to see how I like it...its what we do...
this is the last 700r4 I'm doing..as the nexed tranny will be a Th400 and I will add a overdrive
Last edited by articwhiteZ; 11-11-2016 at 07:16 PM.
The 700 in my car these days has taken some serious abuse for the last several yrs.
Banging 8500rpm and general stupidity from my right foot. Amazing really.
11-05-2016, 01:32 PM
It's great that it sounds like you've got your plan all mapped out for what comes next for fixing it . 
