'68 TH400-need help

[63chevystepside]

Input shaft and tail shaft seals. If it has fluid in it now, that's a good thing. You could install it, replace the fluid and give it a shot.

If I remember right, late 60s (like 68-69) Corvette might have had a slightly lower first gear... but I haven't been involved with those is a long time. The TH400 was used all the way back to 64.

up to 65 Turbo 400's have the good low drum sprag for a trans that may use a trans brake to launch off of, along with the good interemediate sprag that is great for slamming and hitting 2nd gear real hard. You didn't get the good low sprag drum thru 69 which is rarely needed, but thru 69 you did get the good intermediate sprag drum for slamming 2nd which is needed in many cases for racing. So that 68 trans should have the good sprag you need and it about 40% stronger than the roller sprag. So I'd go with that 400 for $100 and that good drum is a steal. I see that good intermediate sprag drum alone selling for as hight as $300 without the sprag. The sprag is another $75 or so. So that 68 400 I'd say is ready to go as far as the hard parts for strength. Then a basic good quality rebuild should do the trick. I doubt you even need the Red Alto clutches. Just go with good Raysbestos clutches in a kit, a new band, filter and run it. If the trans fluid is a nice color run the converter too. Converters don't have seals in them that go bad to worry about how long its been sitting.
I happen to have one of these variable pitch T400 out of a 67 Olds that was behind an Olds 425. Go ahead try to talk me into selling that one !!! Not gonna happen !!! I look forward to building it to put behind an Olds 455 in a Square Body 80's Chevy. And a toggle switch for the variable pitch. Stock stall up, push the switch down and have 1900-2200 stall.

Many of the Buick, Cadillac, and Oldsmobile THM400s produced between 1965-67 were equipped with a torque converter that incorporated the Switch-Pitch variable-pitch stator, which is sought after by collectors and drag racers. These can be identified outside the vehicle by a noticeably narrower front pump spline. Externally the SP version has two electrical connections, where the non-SP THM400 has only one.

I am going to do that 68 400-AND LOL THATS FINAL. Thanks Hot Rod

 

[hotrodpc]

Who do you have building your trannies 66Nova??? You shouldn't be going thru alot of trannies. How much are they charging you for T350's? What are they doing to them? Not much should need done to a T350 for that car, but granted the few things that need done are not cheap. I have seen a hardened input shaft go for over $1000 alone. You need the good wedge sprag for in the intermediate sprag. Wanna get really into, you can lighten the drums and also rollarize the trans where is has all Torringon bearings and no thrust washers too. Are you still running a band? You can actually set a T350 that does not use a band. I do beleive you have to be a full manual valve body for that though which you are probably running already.

 

[63chevystepside]

Who do you have building your trannies 66Nova??? You shouldn't be going thru alot of trannies. How much are they charging you for T350's? What are they doing to them? Not much should need done to a T350 for that car, but granted the few things that need done are not cheap. I have seen a hardened input shaft go for over $1000 alone. You need the good wedge sprag for in the intermediate sprag. Wanna get really into, you can lighten the drums and also rollarize the trans where is has all Torringon bearings and no thrust washers too. Are you still running a band? You can actually set a T350 that does not use a band. I do beleive you have to be a full manual valve body for that though which you are probably running already.

I am not a tranny guy but i have to say iv learned some about all the different ones and thier pluss and minuses---to me that 68 400 is it. I can't pass up durability and dependability of the 400 and it has its perks as a performance tranny with what we talked about. No 66 isnt you are-the 68 400.Nothing worse than a blown 350 in your lap. Sure they can be built(350)but the 400 is sticking out as the one to chose-i havent really heard nothing bad about 400s. Ace was telling me he could build the 350 for 650 out the door with a shift kit and a performance stall conv. and a 1yr warraty. And said his are running at the vally pulling wheels off the ground...but said the 400 was stronger and be idea for the 454. Um wanna beer with that medicine lol? Im taking your advice and doing the 68 400 i feel safe with that decision.

 

[63chevystepside]

Who do you have building your trannies 66Nova??? You shouldn't be going thru alot of trannies. How much are they charging you for T350's? What are they doing to them? Not much should need done to a T350 for that car, but granted the few things that need done are not cheap. I have seen a hardened input shaft go for over $1000 alone. You need the good wedge sprag for in the intermediate sprag. Wanna get really into, you can lighten the drums and also rollarize the trans where is has all Torringon bearings and no thrust washers too. Are you still running a band? You can actually set a T350 that does not use a band. I do beleive you have to be a full manual valve body for that though which you are probably running already.

I am not a tranny guy but i have to say iv learned some about all the different ones and thier pluss and minuses---to me that 68 400 is it. I can't pass up durability and dependability of the 400 and it has its perks as a performance tranny with what we talked about. No 66 isnt you are-the 68 400.Nothing worse than a blown 350 in your lap. Sure they can be built(350)but the 400 is sticking out as the one to chose-i havent really heard nothing bad about 400s. Ace was telling me he could build the 350 for 650 out the door with a shift kit and a performance stall conv. and a 1yr warraty. And said his are running at the vally pulling wheels off the ground...but said the 400 was stronger and be idea for the 454. Um wanna beer with that medicine lol? Im taking your advice and doing the 68 400 i feel safe with that decision.

oops sorry that was to 66-I just got this xmas feeling like a hot flash all over me talking about my training-sorry

 

[hotrodpc]

Who do you have building your trannies 66Nova??? You shouldn't be going thru alot of trannies. How much are they charging you for T350's? What are they doing to them? Not much should need done to a T350 for that car, but granted the few things that need done are not cheap. I have seen a hardened input shaft go for over $1000 alone. You need the good wedge sprag for in the intermediate sprag. Wanna get really into, you can lighten the drums and also rollarize the trans where is has all Torringon bearings and no thrust washers too. Are you still running a band? You can actually set a T350 that does not use a band. I do beleive you have to be a full manual valve body for that though which you are probably running already.

I am not a tranny guy but i have to say iv learned some about all the different ones and thier pluss and minuses---to me that 68 400 is it. I can't pass up durability and dependability of the 400 and it has its perks as a performance tranny with what we talked about. No 66 isnt you are-the 68 400.Nothing worse than a blown 350 in your lap. Sure they can be built(350)but the 400 is sticking out as the one to chose-i havent really heard nothing bad about 400s. Ace was telling me he could build the 350 for 650 out the door with a shift kit and a performance stall conv. and a 1yr warraty. And said his are running at the vally pulling wheels off the ground...but said the 400 was stronger and be idea for the 454. Um wanna beer with that medicine lol? Im taking your advice and doing the 68 400 i feel safe with that decision.

yeah, that was inteded for Nova66. He mentioned he has been going thru alot of trannies and I wonder why. Must not be having them built right I assume. Maybe? All depends on what he having done to them. As fast as his car his, I'm thinking he may do just great with a Powerglide with a Trans brake to launch off of. Never know. The car has to be geared right and set up right to run a PG, but they can sure get your down the track. I know of a guy running a PG in Fox Body Ford Powerplant and I want to say he is doing high 8's in the quarter with it.

I think you made the right decsion on this 66Stepside. The $100 for the T400 and the fact it has the good drum being a 68 model is what made me lean that way. Had it been a 74 T400, I'd still be considering the T350, but with the 400 and the good sprag, I doubt you'll be able to break it with the kind of vehicle and mild motors you are running.

 

[63chevystepside]

Who do you have building your trannies 66Nova??? You shouldn't be going thru alot of trannies. How much are they charging you for T350's? What are they doing to them? Not much should need done to a T350 for that car, but granted the few things that need done are not cheap. I have seen a hardened input shaft go for over $1000 alone. You need the good wedge sprag for in the intermediate sprag. Wanna get really into, you can lighten the drums and also rollarize the trans where is has all Torringon bearings and no thrust washers too. Are you still running a band? You can actually set a T350 that does not use a band. I do beleive you have to be a full manual valve body for that though which you are probably running already.

I am not a tranny guy but i have to say iv learned some about all the different ones and thier pluss and minuses---to me that 68 400 is it. I can't pass up durability and dependability of the 400 and it has its perks as a performance tranny with what we talked about. No 66 isnt you are-the 68 400.Nothing worse than a blown 350 in your lap. Sure they can be built(350)but the 400 is sticking out as the one to chose-i havent really heard nothing bad about 400s. Ace was telling me he could build the 350 for 650 out the door with a shift kit and a performance stall conv. and a 1yr warraty. And said his are running at the vally pulling wheels off the ground...but said the 400 was stronger and be idea for the 454. Um wanna beer with that medicine lol? Im taking your advice and doing the 68 400 i feel safe with that decision.

yeah, that was inteded for Nova66. He mentioned he has been going thru alot of trannies and I wonder why. Must not be having them built right I assume. Maybe? All depends on what he having done to them. As fast as his car his, I'm thinking he may do just great with a Powerglide with a Trans brake to launch off of. Never know. The car has to be geared right and set up right to run a PG, but they can sure get your down the track. I know of a guy running a PG in Fox Body Ford Powerplant and I want to say he is doing high 8's in the quarter with it.

I think you made the right decsion on this 66Stepside. The $100 for the T400 and the fact it has the good drum being a 68 model is what made me lean that way. Had it been a 74 T400, I'd still be considering the T350, but with the 400 and the good sprag, I doubt you'll be able to break it with the kind of vehicle and mild motors you are running.

Me two and i agree on the PG for 66-Sounds like with all that power he is running a PG would do him jusitice.

 

[66nova]

Hotrod, you're right we should not have gone through the trannies we have gone through. Although, it was a combination of cars that I was referring to we have learned who to use and who to stay away from in our area. The th350 I have is the sameone my dad and 3 of our buddies are running. They are Coan built with full manual reverse valve bodies. Dad has been running his for 4 1/2 seasons now and his car is 300+ lbs heavier then mine and runs 9.6s. Nitrous is so violent off the line it is hard on drive lines.

I'm sure our cars would run faster with a glide but again I drive it on the street too much.

 

[63chevystepside]

Hotrod, you're right we should not have gone through the trannies we have gone through. Although, it was a combination of cars that I was referring to we have learned who to use and who to stay away from in our area. The th350 I have is the sameone my dad and 3 of our buddies are running. They are Coan built with full manual reverse valve bodies. Dad has been running his for 4 1/2 seasons now and his car is 300+ lbs heavier then mine and runs 9.6s. Nitrous is so violent off the line it is hard on drive lines.

I'm sure our cars would run faster with a glide but again I drive it on the street too much.

It's one thing to have the ride but to have the power two-You must be one of those good boys Santa vists.

 

[hotrodpc]

Hotrod, you're right we should not have gone through the trannies we have gone through. Although, it was a combination of cars that I was referring to we have learned who to use and who to stay away from in our area. The th350 I have is the sameone my dad and 3 of our buddies are running. They are Coan built with full manual reverse valve bodies. Dad has been running his for 4 1/2 seasons now and his car is 300+ lbs heavier then mine and runs 9.6s. Nitrous is so violent off the line it is hard on drive lines.

I'm sure our cars would run faster with a glide but again I drive it on the street too much.

Cool, so you probably have a good built trans now the way it sounds. And you are right, it driving in the street, the T350 would be alot more fun, and you arnent able to stall out at 5000 + rpm to take from a red light in traffic. LMAO

 

[hotrodpc]

OK, so 66Stepside got that 400 trans today. Turned out the guy was full of shit. It was a 70 trans, not a 68 so I had to get out my T400 bible and see if the 70 had the good sprag drum. Lucky for 66S it did. Now thats no guarentee that someone didn't swap it out in the past. But, he did bring the trans over, pulled it apart enough to get to the sprag. It DOES have the good sprag drum, also new enough has the case saver snap ring, but old enough to also have the prefered Center Support. So he scored big for a $100. Sad thing is though, the guy lied his ass off. Saying the trans should work, it was taken out running and only sat for 4years. The trans has mud and water all thru it. LIAR, it wasn't sitting insdie his garage for 4 years. NOWAY. So it was a great choice to have it gone thru. It'll take a few days to gather the kits, send this filthy case to the trans shop for a pro cleaning with all the mud in it. It all be good when I'm done with it, and he won't be able to break it with what he's doing with it and putting it in. Here are those pics of the differant sprags and sprag drums I told you about 66S, also there a pic of that spiral snap ring I want to update to.