Packard Forum Index » V-8 (1955-56)

You installed the old fluid after rebuilding it?

Ha! Negative.

I don't tend to clarify properly anymore.

I started with STP type F after the trans rebuild.

I typically run fresh fluids for only a handful of heat cycles after rebuilds then change it out.

Supershift will go in tomorrow for the long duration of daily driving.

Gotcha. However I don't see any reason to replace the fluid so soon. Unlike in an engine rebuild where you have to break in new rings and honed cylinders, which creates much metallic debris, there is no equivalent occurrence in a rebuilt transmission. As you probably know, worn clutch or seal material will not damage anything, and there is more of that by far in an old unit than new. Bushings are comparable to the engine bearings.

Likewise, Type F should be adequate, but if you change it, we would appreciate hearing about any perceptible difference in feel or operation.

It's mainly piece of mind as far as changing oils from my racing years!

I will maintain updates

- Engine Flare - Engine Run-Away -

Further testing after Ultramatic rebuild (with new valve body as well)....

Prior to rebuild, the throttle (pressure) linkage setting was on the bottom hole, about centered in the adjustment threads. I could induce flare at a certain throttle depression, other than that it shifted fine.
I left the settings there after the rebuild and experienced more flare. As stated earlier, I moved the linkage to the top hole and adjusted the threads towards the firewall until flare was gone.

After several days of daily driving, It seemed to have flare at specific throttle depression once again. I read thru the STB's regarding this and began to question the valve body not being updated to 56 standards that eliminate flare. I decided to start over at initial settings prior to rebuild (low hole and centered threads) and fine tuned threads towards the firewall until flare was gone.

For now, all is well at the current setting. Shift points are smooth at all throttle levels. I do notice shifting differences from cold to warm as expected.

Fluids ran since Twin Ultramatic rebuild:
- STP Type F
- Amsoil Signature Series Multi-Vehicle ATF (current fluid & compatible for Type F use)

- STP shifts harder
- Amsoil shifts a tad smoother

- Patrician Speedometer Stuck -

Since the car has been running and driving again, the speedo has not worked.
If the cable was attached, it would make snapping noise, so I left it disconnected.

After enduring the fun of the dash removal process, the speedo was removed where I could finally get eyes on it. I found it was seized up. Easy fix luckily. Using a square head screw driver, and lubricating the internals, it easily broke free and now spins as it should.

I installed a new (lubed) cable assembly and it works great!
Speed reading calibration is close as well (verified with GPS).

I also made a new wiring harness while in there for all gauges since things were quite brittle.

There were various changes they did to adjust the shift timing such as adjusting the band clearance, low range servo spring force, shift regulator valve incoming orifice (i.e. the separator plate), as well as the simple throttle pressure linkage adjustment to boost throttle pressure.

Increased throttle pressure gives increased pump pressure. This both helps hold the clutches tighter and also just speeds up the low to high shift a bit since the low range servo fills up faster through the orifice.

Relevant SC's:
-packardinfo.com/xoops/html/downloads/SC/SC-VOL30NO7.pdf
-packardinfo.com/xoops/html/downloads/SC/SC-VOL30NO5.pdf
-packardinfo.com/xoops/html/downloads/SC/SC-VOL29NO12.pdf
-packardinfo.com/xoops/html/downloads/SC/SC-VOL29NO7.pdf
-packardinfo.com/xoops/html/downloads/STB/56T-7.pdf
-packardinfo.com/xoops/html/downloads/STB/56T-2.pdf
-packardinfo.com/xoops/html/downloads/STB/55T-32.pdf (advice in this one is incorrect)

What made you go with the Amsoil Signature Series Multi-Vehicle ATF instead of the Super Shift you listed on 9/4?
I started with Super Shift on my rebuild.

"It's mainly piece of mind as far as changing oils from my racing years!"
I too find that decades on the track lead to significantly different maintenance views and procedures.

HPH - Exactly the info/data needed for this scenario. Thank you so much!

56Clippers - I had both Supershift and Multi Vehicle ATF on the shelf. I decided to test the M/V ATF first, primarily to see if I could detect a difference vs the Type F. As stated, slightly smoother low/high shift.
Absolutely! Years of track time (as well as my trooper years chasing speed all over the highways) has embedded this high standard maintenance interval protocol for all my machines!

All those changes (except low regulator spring) serve to do one of these things:

- Raise the throttle pressure resulting in a faster and more aggressive shift overall. (Linkage, lever extension)

- Lengthen the amount of time before the low range band starts to release, compared to when the high range clutches is primed with 50PSI pressure from the shift regulator valve. (Low range servo spring, band adjustment, and orifice/separator plate)

The essence of the shift is that there is some time where both the low band AND high clutches are partially engaged and slipping at the same time. If there is too much time between these events, then nothing is connecting the engine to the drivetrain and you get RPM flare up that the high range clutches have to pull down. If there is not enough time, then the clutches will fight each other which will brake against the car speed and cause excessive wear. The reason why the latter does not occur is because the shift regulator valve holds the high range clutches partially engaged while the low band releases. The changes overall make the low brake take longer to release which makes sure the high clutches ARE partially engaged first, and the higher overall throttle pressure and therefore pump pressure gives a firmer final engagement.

While there's no major mechanical reason that you could not have a very aggressive high range clutch engagement the instant the low band is mostly released, it would give a very rough and jarring shift. Like if you drive a manual transmission car, you will know that if you shift from 2nd to 3rd, keep the engine RPM the same, and drop the clutch, it will be very jarring. Packard wanted an extremely smooth shift, hence the complexity. And when these are adjusted properly you DO have a smooth shift, without flare.