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Part-Throttle Kickdown
https://www.slantsix.org/forum/viewtopic.php?t=49271		 Page 1 of 2
Author:  FrankRaso [ Wed Jul 11, 2012 9:29 am ]
Post subject:  Part-Throttle Kickdown
Author:  SlantSixDan [ Wed Jul 11, 2012 9:58 am ]
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PTK is definitely well worth having; it makes the car a great deal more pleasant to drive. Definitely add it while you're in there if you can without major hassle.
Author:  Mroldfart2u [ Wed Jul 11, 2012 10:05 am ]
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Quote:
PTK is definitely well worth having; it makes the car a great deal more pleasant to drive. Definitely add it while you're in there if you can without major hassle.
Dan can this be done with mine? Having to 'mat it' does seem extreme in city type driving. Altho I am uncertain of the year of the trans, as it was a transplant that PO's had done to get rid of the 833 od.. :? :cry:
Author:  Doc [ Wed Jul 11, 2012 10:32 am ]
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Sad to say that I have tried doing this conversion on 60-65 904s and was not successful on both attempts. :cry: :evil:

I have successfully done the conversion on many 66 & up transmissions. (both 904s & 727s)

There is some pressure differences between the "2 pump" and the single pump designs that makes the early trans "short shift" and not PTK until untra-low speeds...
When ever you are "mix-n-matching" 2 different valve bodies together... you get into "little known" areas... basically you are on your own.

The issue can likely be resolved by someone with deep hydraulic applications understanding, time and the proper test guages but for me... it's not an easy "bolt-in & go" situation. ( as the parts sellers make it out as)
I need to talk to Pat to see if he has a "fix" to the "short shift" issues I had when doing this conversion...
It maybe as simple as: "drill here", "plug that passage" or turn down the main line or govenor pressure kind of fix... I just did not have the time or energy to figure it out.
DD
Author:  SlantSixDan [ Wed Jul 11, 2012 11:10 am ]
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Quote:
Dan can this be done with mine?
'67-up slant-6 automatics and '71-up V8 automatics have it from the factory -- sounds like yours was monkeyed with (or an earlier-than-those-years transmission was swapped in). Yes, the PTK swap can be easily done on any '66-up transmission.

It'll be interesting to learn what Pat says about the '60-'65 PTK swap; last time I talked to him he said he almost had it 100% and was still working, and that was about 5 years ago.
Author:  Mroldfart2u [ Wed Jul 11, 2012 11:24 am ]
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Quote:
Quote:
Dan can this be done with mine?
'67-up slant-6 automatics and '71-up V8 automatics have it from the factory -- sounds like yours was monkeyed with (or an earlier-than-those-years transmission was swapped in). Yes, the PTK swap can be easily done on any '66-up transmission.
Hmmm maybe an out of adjustment on the kick down? ( i have done nothing to this car other than rescue it from the scrappers, replaced the m/c and driven it. ) The reason car was parked was due to PO's bone headed decision to use dot-5 fluid in the m/c, and having no brakes. How do i determine the year of the trans, or can it be with it in car?
Quote:

It'll be interesting to learn what Pat says about the '60-'65 PTK swap; last time I talked to him he said he almost had it 100% and was still working, and that was about 5 years ago.
Would think after 5 years he would have a 'fix'.

Oh and BTW no i do not have any of the books you have linked up for required reading. I havent had to do ANY work on this vehicle, but it is due for a valve lash adjustment. Starting to sound like the Singer Sewing Machine Granny had... :wink:
Author:  Reed [ Wed Jul 11, 2012 12:13 pm ]
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Quote:
'67-up slant-6 automatics and '71-up V8 automatics have it from the factory
Not true. Last year I rebuilt three slant six transmissions- a 1973, a 1978, and a 1983. All were six cylinder 904s, the 73 and the 78 had never been apart since leaving the factory. The only one of the bunch that had part throttle kickdown was the 78. I know all slant six transmissions were supposed to have PTK, but in my experience not all did. If you ever have your pan off, it is worth it to drop the valve body and double check.

On the upside, I rebuilt the 73 904 using the guts out of a 68 318 904 and a PTK kit from Mr. Blais. It is going strong and working great in my brother's van.
Author:  SlantSixDan [ Wed Jul 11, 2012 1:25 pm ]
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Quote:
Quote:
'67-up slant-6 automatics and '71-up V8 automatics have it from the factory
Not true.
Yeah, it pretty much is -- all of them were supposed to have it, and most of them did; yours are anomalies. Unfortunately for all of us, Chrysler was famous for pathetic quality control and porous specifications in the timeframe you mention.
Author:  Reed [ Wed Jul 11, 2012 1:28 pm ]
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Interesting.
Author:  bigslant6fan [ Thu Jul 12, 2012 5:54 pm ]
Post subject:  .
I'm leaning towards Reed on this topic, I've rebuilt quite a few mid-late 70s ones that did not have PTK. I think the bean counters were out in full force during that dim period of poor quality control.
Author:  SlantSixDan [ Fri Jul 13, 2012 12:48 pm ]
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I'm certainly not going to be the one to argue what's supposed to be the case vs. what has been found to be the case, but how sure are we that these transmissions had no PTK provision? It doesn't make much of any sense that there'd be no PTK in transmissions used in front of Chrysler's super-tall rear axle ratios of the day and sold into a market where everyone else's automatic transmissions had PTK. Remember there are at least two different kinds of PTK housing, one of which visually "disappears" into the rest of the valve body assembly (has no distinct "lookit me, I'm a PTK housing!" appearance).
Author:  Reed [ Fri Jul 13, 2012 3:39 pm ]
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Actually, the PTK assembly is a straight bolt-on assembly, held in place by three screws, that is fairly difficult to miss if you know what you are looking for. Whether or not the trans assembly line workers knew what to look for is a separate issue. The transmissions I rebuilt absolutely were able to have the PTK assembly retrofitted, and the PTK assembly was replaced by a flat metal plate when the trans were built. Again, I don't dispute that the transmissions were "supposed" to have the PTK in them, but we all know lots of things are "supposed" to be true that aren't.

It certainly is nonsensical for there to be no PTK in a transmission installed in front of a 2.2, 2.7, 2.9, or even a 3.2 rear axle gear ratio, but it looks like it happened.
Author:  SlantSixDan [ Fri Jul 13, 2012 3:54 pm ]
Post subject: 
Quote:
Actually, the PTK assembly is a straight bolt-on assembly, held in place by three screws
Right, no debate there -- but one type of PTK assembly is very obviously not a flat metal plate, while the other type has a flat metal plate on its outer end -- the same flat metal plate, if I'm not mistaken, that screws directly to the valve body main casting if there's no PTK.

I wonder if Pat Blais might have detected some rhyme or reason (or none at all) to this -- he spends his days swimming in Torqueflites of every flavour.
Author:  Reed [ Fri Jul 13, 2012 4:25 pm ]
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Absolutely. All I can say is all transmissions I rebuilt were out of passenger cars, except for the 83 904T which came out of a van and had writing on it like it had been rebuilt before. However, when I tore it down I found that it had a worn out clutch pack, so maybe it was also unrebuilt. The only trans with the PTK was the 1978 transmission that came from an Aspen. Who knows. Fortunately it is a very simple matter to install PTK on a post 65 valve body.
Author:  Eric W [ Sat Jul 14, 2012 6:41 am ]
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Reed, if the '73 trans you rebuilt came from my '72 Satellite, it did have PTK. I made good use of it!
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