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A friend of mine purchased a C4 from a reputable builder, rather than having me build one. I've built a few C4's...and all of them were pretty much standard builds with a few internal mods...but nothing "high tech" so to speak. The one he bought he paid out the nose for...I think he gave close to $1500 for it without converter. Anyway, I was over at his house the other day and just happened to grab the input shaft of that high $$$ C4 and it would turn almost effortlessly...and the same held true for the output. All of mine required use of pliers to turn but they always ran great.

I'm putting together 2 transmissions soon. One C4 for Dad's Fairmont and probably another Powerglide for my car, as mine has close to 1000 passes on it. Probably time for a rebuild LOL.

Have you transmission gurus ever given thought to reducing drag? I know on my Maverick, without the driveshaft in the car, it will roll very easily, but when the shaft is installed, the drag of the transmission causes it to be a little harder to push. I would think that it also causes a little extra drag when running. I was also looking at a PTO clutch pack that I had to work with from a John Deere the other day and noticed that each steel plate was separated by a spring, and the springs were held by a common pin...4 pins per pack and 7 steels. There was NO drag when the pack was installed as the plates were held away from the frictions.

Ya'll have any thoughts on the subject? Waste of time?
 

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To tell the truth I'd be hesitant about a new transmission from a rebuilder that turn that smoothly. I always install new bushings when I build transmissions and a fresh set of bushings in a transmssion makes it a bitch to turn over by hand. The power flow through an automatic is all towards the rear and it will free up a few HP to replace all the thrust or as many as you can with needle thrust bearings but that wont have any effect on how well it turns over by "hand" . Once it runs around a bit and the rear bushing works in its a good bit easier. The roller sprag isnt that easy to overcome either new or used.

The last few C4's Ive put together Ive replaced all the thrust washers with needle roller bearing sets including 9 and 10 . All except for the small one at the end of the pump stator housing that is. LOTS of machine work involved in replacing all the thrusts and it has to be exact or the clearance wont be right when your done. I used mostly TH350 stator and a few mcmaster carr generic torringtons with races. The #10 was a C6 planetary set. Probably saves a few HP but it sure keeps the oil clean .

If the clutches are set loose then the input will turn free and you may even gain a tenth or so at the expense of transmssion life. I can afford to lose a tenth especially as a bracket racer where it doesnt really matter how fast I go.
 

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At the time my brother decided to go racing again my C-4 program was not as far along as it is now.

So he decided to get a local tranny buiulder to do his C-4, his input would spin the same way.
Tranny did not last long, way too much clutch clearance in both packs and the clutches were installed dry. The fluid I soak my clutches in causes them to drag and with the tighter clearances the input will not spin easily.
 

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Never seen an assembled tranny spin that easy on the input or the output.......now various parts of the transmission will spin much easier when the thrusts are replaced with bearings but that's just having the parts out on the bench and spinning them.
 

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The fluid I soak my clutches in causes them to drag and with the tighter clearances the input will not spin easily.
I am getting ready for a rebuild so I am curious what fluid you use and why. Usually I hear people using trans fluid.
 

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Mavman, I have brought the clutch drag subject up on acouple of occasions and totally agree with what your saying. I never thought about the spring idea though... but it would be hard to implement in a C4 due to the centerless steels and frictions plus the thinness of the plates.
I hate the thought of "giving" hp away. We mess around with rollerizing everything (ok...some of it for reliability over the thrusts) but the tight clearances that are run to help the directs frictions lives, may well be soaking up the additional hp that your new $600 intake produces....
Check out the post "Some interesting results... " on here for some opinions on clutch drag.

<font size=-1>[ This Message was edited by: cmf60 on 5/30/07 10:08am ]</font>
 

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My buddy bought a professional build roller C4 that had a lot of clutch clearance. Twice what I normally run. After breaking the bellville spring a couple of times do to high pressure, he let me do his last rebuild. I set the clutch clearance at .005" per clutch. He ran the car last week at Indy and equalled his best ever ET and 60'. I'm not convinced that the tighter clutch setting is dragging THAT much power. No one has proven it to me yet. This was a fairly apples to apples test.
 

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Many years ago I happened through a shop where a high production builder worked.
He could pump out 30 transmissions a week.

I turned one of his shafts in a Th350 once.
It spun like a top.
I was interested so watched for awhile.

Dry assembly.

Not my cup of tea thank you very much.
 

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Does anyone here think/know that rollerizing a C4 is worth ET at the strip?
 

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On 2007-05-29 21:36, cmf60 wrote:
Does anyone here think/know that rollerizing a C4 is worth ET at the strip?
Would be surprised if it was measurable. The biggest thing I gained was not replacing washers every year and no brass in the pan.
Unless a thrust washer was galling the film of oil would limit the friction quite well.
But on 2nd thought they must gall somewhat to wear so fast behind a bunch of HP. Still not measureable though in ET or MPH.
 

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On 2007-05-29 21:25, fairmont510 wrote:
30 TRANSMISSIONS A WEEK!!?? And you said "Builder"meaning ONE MAN!How Many Days in his week and Hours?
Yes builder, one man.
There was no R&R and he had a part time flunky washing parts.
So I guess it was more than one man.
40 hours a week.
 

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On 2007-05-30 03:05, Mario428 wrote:
On 2007-05-29 21:36, cmf60 wrote:
Does anyone here think/know that rollerizing a C4 is worth ET at the strip?
Would be surprised if it was measurable. The biggest thing I gained was not replacing washers every year and no brass in the pan.
Unless a thrust washer was galling the film of oil would limit the friction quite well.
But on 2nd thought they must gall somewhat to wear so fast behind a bunch of HP. Still not measureable though in ET or MPH.
Ok, I was fishing for a comment that wasn't forth-coming.....so I won't flog a dead horse.
 

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The cost of rollerizing a C4 is prohibitive unless you have over 600 HP.
Your friend had an $1800 C4? If he paid that much for it I wonder if it was rollerized. With clutches that are soaked before installation and .005" to .010" clearance per friction the input shaft will always have drag on it. You don't need pliers to turn it but it won't turn easily - even with full roller case mods.
My two cents worth..
Paul
 
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