Hot Rods 1955 Buick Dynaflow trans issue.

I have a 55 Buick I picked that was sitting for about 17 years. Rebuilt fuel pump, replaced water pump, full tune up, new oil and she started right up in first try. Engine runs great and is quiet. After warming up the engine I checked the trans fluid and added a a quarts as it was low. No leaks on engine or trans. When I put it in drive or low it barely moves even when reving engine. When I put it in reverse, it works fine. Wonder if it just needs to run for awhile to get things flowing because it sat for so long. Anyone run in to this problem and were able to fix with out a rebuild? Thx

 

I'm no Dynaflow expert but automatic transmissions in general can have problems after sitting for years. Seals dry out and can split, components can rust and even stick together. You are probably going to have to rebuild it but I have had good luck with K&W Trans-X. You don't have anything to lose at this point.

 

They act like that when the front pump is bad. Aside from the torque converter, a normal guy work on and understand the guts of those. Also the linkage has to be adjusted right.

 

Hmmm haven’t thought about the linkage. It’s all original and doesn’t look like it’s been touched but I’ll take a look at the manual and see if I can find anything. Also heard of guys adding a secret sauce to lube up the gaskets. Don’t know what that secret sauce is. Anybody heard of adding something to the trans oil?

 

Find a book that talks about checking the pump pressure.

 

I think that's what the K&W Trans-X is that @onetrickpony mentioned above.

 

I would try the Trans-X additive and run it some to see if the seals swell up. It may not leak now, but it will. Dyna-Flows are not nick named Dyna-Leak for nothing. Very few shops have the expertise on those units.

 

I had this problem but only in high range. It needed a rebuild and it was expensive, and it was hard to find someone who knew how to build a Dynaflow.

What makes Buicks a pain is that a modern transmission swap is made difficult by the torque tube design. If eliminating the torque tube you have to go to a four link, or GM pickup trailing arms to support the suspension, in addition to an open drive rear-end. It get's complicated real quick.

So, I just had the dynaflow rebuilt instead of doing all that.

 

I know that a lot of people think additives are snake oil but in your case, as in mine, there’s really nothing to lose. I used Blue Devil rear main seal stuff in my engine and Lucas transmission stuff in the trans and it’s running and driving fine after 50+ years in storage. Look for something that says that it lubricates and rejuvenates seals and give it a try. The suggestion about checking the line pressure is good too. If there’s little or no pressure nothing will help.

 

In addition to this, the 53-56 engines had a different bell pattern, requiring the use of a transmission adapter and custom converter. The alternative is a later 57-up engine and 64-66 ST400 transmission.

 

Have you checked the fluid level since you topped it up? Did you check it how you’re supposed to? I’ve no idea about a Dynaflow but manufacturers have different ways of checking the fluid, hot/cold/engine running/engine off. If you checked it when it’s off and it’s supposed to be when it’s running you could be way short.

 

Yup, fluid is at correct level while warmed up at adle.

 

Thanks one trick pony. I'll order up some and give it a try.

 

You can adjust the bands on one but what does the fluid smell like?

 

Fluid smells normal to me. Nothing odd.

 

Have you pulled the pan and cleaned /the filter/ screen. I have no dynaflow experience, but had a borg warner in a 55 stude do the same. It sat so long the debris settled in the filter and blocked the flow. Worked after I cleaned it.

 

I haven'yt done that. I'll try the K&W tonight. If that doesn't work I'll drain it and pull the pan. Thanks

 

a shade tree additive is 4 oz dot 3 brake fluid. makes the seals swell. don't go over 8 oz.

 

If you do need to rebuild it, take it to Leon's Transmission on Reseda Blvd. They're local to you from what I see under your avatar. They rebuilt the Dynaflow I had in my '61 LeSabre back in 2005. Did a good job.

 

The earliest Dynaflow information I have is for a 58 twin turbine. It looks like there are 4 pressure taps, front pump, rear pump, ac***ulator, and stator. On the left side of the transmission the furthest forward tap is the stator tap, if you have one. The next tap is the front pump tap. That's the one I'd start with. The ac***ulator tap is on the ac***ulator which hangs down from the right of the transmission. The rear pump tap is at the rear just above the pan rail.

They list 2 rpm ranges, 500 rmp, and 1000 rpm. They also want the tests performed with the rear wheels off the ground. I'm sure that is so there is some rear pump pressure.
Low Range 500 rpm F-120, R-90, A- 115 S- no specified pressure at 500 rpm
Drive 500 rmp F-90, R- 90, A-80 S-10
Reverse 500 rpm F-120 there is no listing for the other ports

Low Range 1000 rpm F-180, R-180, A-175 S-no specified pressure at 1000 rmp
Drive 1000 rpm F-90, R-90, A-175 S- 70

So internally the Dynaflow has a low band, a reverse band and a clutch for drive. I would imagine that the pressure test will show that you have sufficient pressure at the front pump to apply the reverse band. I would also imagine that you have low pressure at the front pump in drive or low. This would indicate an internal pressure leak. The only repair is to remove the transmission and go through it.

The only hard part with this and the cast iron PowerGlide, is the fact that they are cast iron and very heavy. I think any competent transmission man would be able to repair it if you supply a factory service manual. Very few shops are going to have Dynaflow manuals.

 

Put in about 8oz of K&W. Let it get warm up and gave it a try. She starts moving slightly but doesn’t really get moving. You can tell it’s slipping. Going to let it sit for awhile and see if it makes a difference.

 

In case you've never owned or driven and old Buick with a Dynaflow . . . This is pretty much how they operated when new.

These Buicks were never a rocket ship when accelerating from a dead stop. Their multi-element torque converters weren't nearly as efficient at torque multiplication as later style torque converters are.

Give the K&W "snake oil" a little more time to work. Don't just get the fluid "warmed" up. Get it up to something closer to normal operating temperature. Since you can't drive it to do this, you might want to give this a try.

Start it up, set the brakes, put it in Drive, then hold the throttle at a high idle speed. Do this for 30 seconds or a minute. Let the engine return to a normal idle speed, shift it to Low and repeat the procedure. Then do the same thing again, shifting to Reverse. Repeat this cycle a few more times to build some more heat in the A/T fluid. You probably won't notice any immediate improvement but by letting this sit and cool for a few hours it should give the additive a better chance to flow thru every thing and do its job.

You've got nothing to lose. Good luck!

 

Thanks Claymar, I have owned a few Dynaflows in my day. A 53 and a couple 55s. This is the first one I’ve owned that doesn’t have a leak. Well not yet. I give your instructions a try. Thanks.

 

https://www.hometownbuick.com/1955-buick-dynaflow-transmission-specifications/

 

With mine, I put the car on jack stands and ran it through the gears and let it run in each gear for a few minutes. That way the trans doesn't really see any load. I kinda wanted it to circulate some fluid and "limber up". After doing that a few times, then I put it on the ground to try to move the truck.. it got better each time.
You might want to just bite the bullet and pull the pan now. I didn't, but once I finally pulled the pan, I wished I had done it to start with. I subjected my poor old transmission to this.... Hard to believe it actually worked.

 

Wow that looks bad. I guess if this doesn’t work I’ll pull the pan. Also looking in to a local trans shop to see if the can service it. Jimmy959 sent me a shop close by.

 

Well then you've got a better sense of whether it's working or not than I do . . .

 

Update; tested it out today. In low if I give it gas it slowly engages and starts driving but it takes a bit. In Drive it’s less and doesn’t fully engage. I can’t really test it for longer distance as my driveway in only 100 ft long. I live up on a hill and if I drive the car down the driveway I’m afraid it won’t make it back up. I guess it’s time to tow it to the shop.

 

I hope they can help. It was almost 20 years ago when they serviced my Buick (don't have it anymore, I sold it a while back). I did a quick Google to see that they're still there when I saw your post. Good luck!