Packard Forum Index » Post-War (1946-54)

Hi Guys:

I know, I know, this one will make alot of us cringe! A Chevy 700/R4 on our straight 8, YIKES! Well I don't have a problem modifying my Packard. As long it is a good functional modification. With nothing bastardized and all original parts saved. After all, the fellow with the Packard Panther project. Did some wonderful functional modifications on his 1956 Executive, very impressive.

I found this link while browsing,

transmissionadapters.com/Packard%20to%20Chev%20adapter%20kit.htm

Sure looks pretty! The 700/R4 is a tough transmission. With overdrive and lockup converter too. Have any of you tried this?

Reason for asking, I've got an Ultramatic that's leaking. At 65 the refilling process is becoming a chore. And the wife is bugging me about the oil spots on the driveway. Before I bring the Ultramatic to that fellow in Va. For rebuild at $1800.00+. This might be an alternative I can handle.

I would think a Drive shaft from the same donor car as the transmission, would be needed. And fabricated to fit the rear companion flange. Along with a rear trans mount and a vacuum or electronic throttle valve setup. I'm not sure what the 700/R4 takes? And what about the Lockup converter electrical signal. wasn't that done by Computer? Something would need to be fabricated there.

Uh-Oh, becoming complicated. Maybe the fellow in Va. is the correct choise.

But if any of you try this, please post the results.

Thanks
Warren

There was some discussion of this adapter a few months ago when it came out and believe another poster with a 53 was also considering or is in the process of doing the conversion. Can't remember who it was right now.

Several Chrysler Torqueflite conversions as well as a few various model Hydramatics have been done. There was a shop (no longer doing it) that modified the case of the R4 to fit directly on the Packard bellhousing. Believe this one with the adapter is new enough that not many are aware of or have tried it.

If your only problem with an Ultramatic is a leak, complete replacement sounds a bit drastic. I guess you've got a pre-55 as you say filling it is a chore - you could reseal the trans, or cut a hole in the floor over the filler neck, or look for a removeable plate towards the rear over the breather and fill from there.

Leaking seals at the throttle pressure shaft, selector shaft and rear tailshaft can be replaced with the transmission in place.

I kinda go with Owen. All the seals to make an Ultramatic tight as a tick come to about $50 and can be done in a day by any decent shop. Seems like a lotta trouble--unless you are looking for faster dig off the line.

I may be able to shed a little light on the torque converter clutch (TCC)

Although the TCC in the 700R4 is controlled by the ECM in factory installations, getting the TCC to work without an ECM is nothing new. While there are aftermarket kits to accomplish this, many rodders using this trans in other cars have been doing it for years, from scratch.

The "signal" to engage the TCC actually originates with the 700R4 transmission, via a pressure switch, which makes or breaks a connection to ground; some have N.O., others have N.C. contacts. The ECM merely acts as a switch for the TCC solenoid, but likely incorporate other inputs in deciding when the TCC should be engaged.

You can use that pressure switch to control a relay, which is used to energize the TCC solenoid and engage the TCC. However, I believe that you would also have to wire up a brake pedal switch to the relay control circuit to disengage the TCC when braking.

Mind you, I've never done this myself with any 700R4 in any car - merely theorizing. You will need to exercise your own due diligence.

However, aside from the cost of installation/adaptation, I think you'll find it more costly to overhaul a 700R4 than any Ultramatic. Sooner or later EVERY automatic requires an overhaul.

Thanks Owen, I know I have a small front seal leak, So it will need to come out. It also leaks around the throttle & selector shafts.

The last time I had it out it seemed to have some slippage in drive, from a standstill. Although I think I correted this with a throttle linkage adjustment. So I'm not entirely sure all is well with this transmission.

Front pump seal could be old and tired, or the leak could be a sign of bushing wear.

However, before removing the trans for anything, I'd drain it (including the converter) and refill with Type F or FA fluid and see if that helps alleviate the slipping. (By "drive", I assume you mean high range, with selector in "H" position.)

Thanks BH for the description of the 700/r4 lockup circuit.

You guys sold me, I'll be sticking with the Ultramatic. And yes BH, that slippage was in H range, from a standstill. L range was fine. Although, as said, in the previous post. I think I corrected that with a throttle linkage adjustment, or did I?

IIRC a 700R4 trans' prior to some certain year were not ecm controlled.

this sounds interesting ,but i wonder besides the fact that 700r4 parts are more abundant, if there would be a benefit to an overdrive trans vs the ultramatic in performance and mpgs i don't think i would do the conversion anytime soon