Jump to content

Dynafow to a TH400 on my '63?


Recommended Posts

  The Dynaflow in my '63 Riv has been raining trans fluid from multiple area after an internal rebuild several years ago at a shop that no longer services them. The trans seems to operate smoothly, the (synthetic) fluid is bright red and I am aware of the Dynaflow "belch", but before I explore resealing options, I was wondering if changing to a TH400 is a prudent move, as that was a major change for '64 and the 400 is widely considered a great design.

   My car is a driver and I'm not beholden to keeping the Dynaflow just for originality's sake. I also know that Russ Martin is a great recommendation, but I'd also like to hear from anyone who has swapped to a TH400 and what else may be involved, pros/cons of such a conversion, etc.

   I'm aware of this link where RivNut suggested Russ for some conversion parts, but maybe some of you can chime on this overall subject so I can gather some first-hand data to help me make a decision.

https://forums.aaca.org/topic/305527-63-dynaflow-to-turbo-400-conversion/?tab=comments#comment-1704117

  Thanks in advance and Happy 4th!!

 

 

 

Link to comment
Share on other sites

Things to think about:

Carb, need a 64 carb to connect to electric kick down

          Need kick down switch, bracket and wiring

         Vacuum port for modulator

Starter motor

       63 starter motor has longer nose to reach ring gear

Flex Plate and adapter or 64 crankshaft

Shifter mechanism along with neutral safety switch

Drive shaft 

      Same length?

      Same number of splines?

 

I've never done one but these are a few things I could think of off the top of my head.  Someone who has done it can probably add a bunch more.

 

 

 

 

Link to comment
Share on other sites

Drive shaft and trans mount are also different. Have to relocate mount holes for the mount. Either keeping the dynaflow or going to a 300/400 you would probably have to rebuild them also. Most likely cheaper to get the dynaflow worked on. 
 

Ray

Link to comment
Share on other sites

Many moons ago, I bought a '63 that had this basic swap already done. However, the swap was a complete 65 motor/trans into the '63 chassis.  It came with a Pontiac floor shifter lever with a cable.  I found the correct linkage and fixed that but I did notice that the original Dynaflow trans mount had been cut and welded to fit the 400 trans and 63 chassis.  I think that also required drilling new holes in the X frame.

 

You'll save money by buying transmission fluid in bulk and sitting a drip pan under the car.  

 

Have you actually looked to see which seals are leaking?

Link to comment
Share on other sites

The mechanics over in the next county said those engineers made a lot of design flaws in the Dynaflow. And it's hard to get one to work right. They can schedule a swap any time after the 4th. Well, maybe after the 6th.

mechanics.jpg.7437e8b6e0984c4b83bdc778e1c09dc9.jpg

  • Like 1
  • Haha 4
Link to comment
Share on other sites

6 hours ago, 60FlatTop said:

The mechanics over in the next county said those engineers made a lot of design flaws in the Dynaflow. And it's hard to get one to work right. They can schedule a swap any time after the 4th. Well, maybe after the 6th.

mechanics.jpg.7437e8b6e0984c4b83bdc778e1c09dc9.jpg

 

Don't them boys work at Wanker County Auto?  

 

Link to comment
Share on other sites

Thanks all. RivNut wrote:

"You'll save money by buying transmission fluid in bulk and sitting a drip pan under the car. Have you actually looked to see which seals are leaking?"

  When I had a safety check/inspection done recently at my shop that primarily services older cars but does not do a full trans rebuild, they essentially said the same thing as Ed - there's no need to change the fluid since by replacing what leaks out, you're essentially doing a flush and refill. It's leaking from so many points that it needs a complete reseal, and he did give me some contacts where I might get that done. And yes, I keep a drip pan underneath like I do with my other older cars.

Some questions/thoughts as I determine the best way forward :

 What actually causes the Dynaflow "belch"? Does that mean the fluid comes up from the dipstick tube or is there a vent or other feature  designed into the trans to spew out any excess fluid?

 Can someone tell me how long the OEM trans dipstick should measure for a '63 Riv (with a 401)? I wonder if sometime during the cars life prior to me owning it (2015) that it was changed for some reason or other.

 Thanks for any thoughts. I'm leaning toward staying with the Dynaflow but wanted to learn more about what's involved with a changeover to a TH400.

 -Jan     

Link to comment
Share on other sites

You may laugh, but try putting a pint of dot111 brake fluid in the trans. it will help to swell the seals.  This is an oldtimers fix for DynaFlow leakers.

 

Tom T.

  • Like 3
Link to comment
Share on other sites

Yes, DOT 3 brake fluid!  I had a '67 Lincoln that used to pause before engaging reverse.  A transmission guy I knew recommended the same thing and in under 100 miles of driving it was engaging reverse as soon as I moved the lever.  ;)

Link to comment
Share on other sites

Yes, it's very photogenic - provided the camera doesn't get too close. It's very rust-free, a nice driver, and largely original except for an 80's-era repaint which has now seen better days.

  • Like 1
Link to comment
Share on other sites

On 7/3/2021 at 9:46 AM, 60FlatTop said:

The mechanics over in the next county said those engineers made a lot of design flaws in the Dynaflow. And it's hard to get one to work right. They can schedule a swap any time after the 4th. Well, maybe after the 6th.

mechanics.jpg.7437e8b6e0984c4b83bdc778e1c09dc9.jpg

I live in North Alabama, and I swear that could be my hometown, lol.

 

Link to comment
Share on other sites

Oil leaks are fixable. I chose to do the swap rather than rebuild my Dynaflow. I'm not done yet, I still have the engine out for a rebuild. But I've had to do everything everyone has already said. It's not that big of a deal really, but it takes some creativity to get it all back together. Could you swap in a 65 Shifter? That would solve that issue. The bellhousing is a direct bolt on. But that's about it. 

 

 

 

 

  • Like 1
Link to comment
Share on other sites

If you’re having the engine rebuilt, swapping a 64 - 66 crankshaft for the 63 crankshaft would solve a lot of problems. You’d then only need the 64 - 66 starter motor, as well as the other 65 items.

Link to comment
Share on other sites

Posted (edited)

I had the Dynaflow for my '60 Electra rebuilt over Good Friday weekend. Dropped it off Tuesday and picked it up the following Tuesday. They kept it one extra day to check a drip from the torque tube which turned out to be residual from the repaired leak. No leaks.

 

The parts, an overhaul kit and bushing kit from FATSCO and a new torque ball seal were $600. Labor was 3 hours to remove/3 hours to install. With 12 hours of bench time, about what I had figured. Labor was $1800. Total $2400 was a pleasant surprise. I was prepared for $3200-$3600. I do have a '64 Riviera with a Turbo. There is no noticeable difference between driving either of the two with their originally designed transmission.

Edited by 60FlatTop (see edit history)
Link to comment
Share on other sites

I agree with Bernie. Only reason I swapped mine for a 4L60E was boredom. Covid made me do it! Along with a bunch of other enhancements. Drove cross country with the Dynaflow at 70-80 mph, 12 mpg and it did leak a little, but not enough to add any in the 3000 miles home. Maybe Bernies guy is close enough to let him straighten the Dynaflow out. $2400 seems cheap in todays world. My conversion is at least double that not including my time which is a whole bunch more than 18 hours.

 

Ray

Link to comment
Share on other sites

Thanks Bernie and Ray - your input is much appreciated! Thanks to a recent feature in the 'Riview' magazine I was given a good recommendation from a fellow ROA member here in San Diego about a shop that knows its way around Dynaflows. I'll bring my Riv in the week of the 19th to assess things and will provide an update after that.    

  • Like 1
Link to comment
Share on other sites

23 minutes ago, JanZverina said:

Thanks Bernie and Ray - your input is much appreciated! Thanks to a recent feature in the 'Riview' magazine I was given a good recommendation from a fellow ROA member here in San Diego about a shop that knows its way around Dynaflows. I'll bring my Riv in the week of the 19th to assess things and will provide an update after that.    

I was going to say if you have a competent shop that is familiar with the Dynaflow, getting yours gone over and resealed would be the best route by far vs starting down modification road which could leave your car undriveable for a long time. Along with being first year, to me the Dynaflow is what gives a 63 Riv unique character.   

  • Thanks 1
Link to comment
Share on other sites

The most IMPORTANT area of the DynaFlow is the torque converter.  One MUST take tolerences due to clearances & replace thrust washers/bushings, wherever possible, with Torrington needle bearings. Makes a whole new experience with the driving pleasure.

You must remember in Drive the ONLY thing powering the rear tires is all fluid drivin'.

 

Tom T.

Link to comment
Share on other sites

  • 4 weeks later...

(Almost one month later)

An update on my Dynaflow woes with my '63 Riv: I picked up the car yesterday from the trans shop. TelRiv again gets the brass ring, as several leaks were indeed from the converter bolts. Also leaks from the accumulator seals. The shop kept the car sitting for several days just to make sure they caught everything. The other thing I learned - and I'm sure many of you know this already - is that synthetic ATF, which was recommended when I had the trans rebuilt 5 years ago - will leak past any seals faster than Dex III, etc. If anyone in the San Diego area is looking for a shop that knows their way around older transmissions, let me know.

   

 

Link to comment
Share on other sites

On 7/7/2021 at 11:05 AM, drhach said:

Could you swap in a 65 Shifter? That would solve that issue.

Although I have yet to do the swap. My assessment is to mount the '65 shifter 5/8" higher inside a gutted '63 shifter. This way the fore/aft sweep is not as long. Also, the chrome at the bottom of the shifter tube may or may not just reach the plastic slider.

On 7/8/2021 at 12:32 PM, telriv said:

The most IMPORTANT area of the DynaFlow is the torque converter.

The Dynaflow torque converter IS the transmission. The pig behind it is a range selector for reverse, intermittent Low, park pawl, pump and speedo output.

On 7/7/2021 at 1:29 PM, BulldogDriver said:

I agree with Bernie. Only reason I swapped mine for a 4L60E was boredom. Covid made me do it! Along with a bunch of other enhancements. Drove cross country with the Dynaflow at 70-80 mph, 12 mpg and it did leak a little, but not enough to add any in the 3000 miles home.

Having practically all the parts to do a Dynflow to ST400 swap with either the 13 or 12" variable pitch torque converters (have several), there's nothing stopping me in proceeding except $$$. However, there's more: 1) Driveshaft related concerns to avoid vibration (drilling holes for desired angles), 2) Troubleshooting during or after the swap (can of worms?), 3) My Dynaflow is GOOD! No leaks and doing the job just fine!

1 hour ago, JanZverina said:

I had the trans rebuilt 5 years ago

I'd stick with your Dynaflow then. Mine was rebuilt 1989ish, leaked like a sieve upon install. I then had it towed to the shop that did the job where they removed the Dynaflow and started over then re-installed. During this time, they broke my turn signal cable man-handling my dis-abled Riviera in and out of their service bay. But again, no leaks since!

 

On 7/4/2021 at 1:08 PM, JanZverina said:

Can someone tell me how long the OEM trans dipstick should measure for a '63 Riv (with a 401)?

This was never answered - 21" Long

image.png.ddd904b5b509f3a926834b810295c955.png

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...