Dyna-Slip

I've got a 60 LeSabre, 401 and a DynaFlow. At first, the transmission didn't want to pull when cold, but after regular driving that cleared up. Low gear doesn't work. Now, the trans pulls smooth until you get into hills. Then the trans starts to get warm and slip, along with bringing up the cars temp. I just flushed the tranny with new fluid and Lucas additive. The old fluid was relatively clean.

Any ideas as to what my problem is? My uneducated guess is the pump, but I really don't know anything about a DynaFlow than what I've read online.

Thanks
Evan

 

if you end up pulling the trans, I would swap in a 1965 buick switch pitch turbo 400. it's the best trans GM ever built for my money.
I've owned 2 1960's and never had a problem with either. so if its a simple fix I'd keep it stock.
hows that for no help or advice??

 

Sounds like the pump, but that's just A/T knowledge, not Dynaflow specific.

 

It would sure be handy to have a shop manual for this specific car and trans combo. With the proper gauge it should be fairly easy to verify if you have a pump issue.

Don't have any experience with Dynaflows, but are these trans sensitive to throttle pressure adjustments? Maybe some sort of linkage between the carb throttle lever and the transmission that's out of specs? There's no vacuum modulator on these, is there?

 

Not sure if this covers 1960 or not. Unfortunately The troubleshooting pages are toward the end

http://cogpro.com/chapters/D-Dynaflow/index.htm

 

Dan, Thank you for posting that. I have a 63 Riviera I'm putting on the road, and that will come in VERY handy.

 

Dynaflo transmissions will not engage lo range unless manually selected. If put into "D" they will start out in direct and stay there as designed. The torque convertor does the work and allows the engine pull the car up to speed.
Also, the torque convertors were designes with a switch pitch set up. Usually lever operated on the dynaflos, they would engage (so to speak) high stall when the accelerator pedal is pushed down far enough. This could feel like slippage if you are not used to it. It is much like driving a modified automatic with a high stall convertor, except that when the throttle is lifted a bit, the dynaflo goes back to the normal/low stall speed.
If the trans is actually slipping, it should start to show signs of burnt clutches in the fluid. Typically this is notrced by the burnt fluid odor and brownish color.
If it is infact slipping only on hills, you might look to see if the pickup is damaged/clogged or missing in anyway where the trans cant get fluid when on an incline.
Often a slipping trans will slip under load, wether on a hill or just acceleration. If it is more than the obvious, I would recommend a shop manual for the car which will have diagnosis and repair of the trans included in it.

 

Thanks for the info everybody. Last night, I ran across the linkage that engages the switch pitch. I hooked it up, the trans seemed to run better, but then started to get hot and slip. The fluid still looks alright, and smells normal. The "slip" occurs on hills and stop and go traffic. Does a DynaFlow have a filter in the pan?

 

Hi, i HAVE a 1956 buick special station wagon that leaks trans fluid i pulled down the pan when i changed the fluid and she did have a metal filter and was able to clean it but looks like i will have to replace the front pump seal.Hope this helps.Bruce.

 

Thanks for all the input. I checked y front pump pressure, it read at 95 psi, so it's good. My high accumulator only read around 50, which is not good. The gasket looked good, the check ball was functioning, etc, so it's probably something internal. The low accumulator read 0, should run 10 psi. I found the check ball stuck due to the retaining pin being bent/ broke. Fixed that, now both accumulators are ready to go back on. While I was at it, I pulled the valve body to clean it. Everything looked good, turns out there's not a lot going on in a DynaFlow valve body (as compared to the TH700R4's I've been in!)

Now I can't find the reverse piston or the spring to it that are sandwiched between the valve body and the servo body! Hopefully it'll turn up soon or I'll be hunting for a dead Dynaflow donor to rob!