C6 Problems--Advice Needed

[RJP]

Ok so the input shaft is good. Lets assume that everything connected to the input and behind the front pump is good also and you still want to rebuild the trans. Before you start shopping for a rebuild kit you need to determine IF the trans is original to the car. 66 Galaxies have a large and small green dot on the gear selector. Referred to as the Cruise-O-Matic similar to the old FX- MX iron case B/W 3 speed trans. I mention this because 1966 only has a few differences from the 67 and later "Select-Shift" C6s. Obviously the valve body is different and can be identified by both the V/B and the transfer plate have C6XX part numbers and generally cannot be upgraded to the select shift V/B needed for low-2nd-high gear shifting and the ability to hold what ever gear you put the selector in until you shift into the next gear, either up or down. Any V/B with a p/n C7XX and up to a D3 or D4XX V/b [ can be used for a shift kit maintaining the select shift feature. The next thing you need to confirm is the 1966 only forward clutch uses coarse spline friction clutches and common rebuild kits will not have these coarse spline discs. I know some builders have use the Hi/Rev frictions in the forward as the splines are the same. Personally I've never done it and I don't really recommend it as the friction materials are different, at least they used to be. In order to use a standard, over the counter rebuild kit with common frictions and steels the forward clutch will need to be changed. As I pointed out in a past post the forward clutch hub for 66 thru 72 or 73 have 31 splines, later have 30 splines so you'll need to be careful what forward hub you need or you might be buying a 31/30 input shaft to go with the later forward clutch.

[Diogenes]

Yeah, identifying the year is going to be a challenge. The car was a column shift, but I scored a nice 7 liter interior and converted to console and floor shift. The tag on the trans is missing, the pump casting is C6AP, but I believe all the pumps are the same. The case casting is D3TP. This is not going to be fun identifying.

I spun the input shaft, sounds like some squeaking going on, but the trans is drained. I pulled the shaft and put it in the converter, it spins, but sounds like a bunch of gravel and ball bearings spinning inside--it don't sound good.

I GREATLY appreciate all the thoughts and expertise (and time) shared. Thank you.

[RJP]

I think you have found your problem...the converter. It should not sound like a box of rocks rolling down a hill. At this point it would be a waste of time and money to have the converter split and inspected. With what you have described it would not even be worth core charge. Regarding the case p/n of D3TP it sound like it is from a truck but the main thing you should look for is the detent mechanism for the shifter. Early shifters use a ball & spring in the valve body and later, say in the 73-74-75 range [I don't remember the exact year] they switched to a "rooster comb" and a loaded flat spring/roller so be careful about purchase of a rebuilt v/b if you choose to go that route. As for the internals of the v/b there are a couple of differences such as check valves and I believe spring tensions so if you do a shift kit you need to know what vintage v/b you have. If it were mine and the trans is out and on the bench I would do a complete rebuild if for nothing else to clean any debris that seems to migrate thru out the system after a component failure no matter where that failure is. Also it is a good time to inspect for any pending component wear, damage and such and to bring all component clearances back into spec. Don't assume the converter debris is confined to just the converter. You will need to flush out the cooler lines and heat exchanger before putting a rebuilt trans back into service as fluid from the converter goes to the cooler before returning to the output shaft support bushing and sprag clutch. Look for damage to the sprag rollers and races along with junk getting into the main support bushing. There are commercial flushing kits available to do this. 

[gt350hr]

+1 It sounds like it broke the sprag in the stator. Rare but it does happen. Trash goes everywhere!

[Diogenes]

I pulled the pan and valve body tonight. There is light glitter in the bottom of the pan, nothing heavy, but still nothing good. It obviously needs to come apart.

casting #s on valve body are D2AP on the casting on the trans side, C7AP on the piece facing the pan bottom.

I'll need to replace the converter, but not planning on dropping $450 to replace the one that failed. Not sure what impact a B&M or TCI converter rated at 2000 stall will have on the cars performance ($200-240), based on the failed convereter is allegedly a 2400-2700 stall. I'm way out of my sphere of knowledge here.

[shady]

the last B&M I used cost me a tranny. Went to a FTI.

[e philpott]

Throw a stock converter in there for 125.00 and go

[Gaugster]

I'm just catching up on this thread. Great read and great advice. Two questions I have though. 1 - Did the dipstick ever show signs of bubbles in the fluid? A moot point at this stage but I'm curious as I didn't see any mention. 2 - What servo does your C6 have? D, R etc... and does the type of servo affect the decision to rebuild vs replace?

Good Luck!

[Diogenes]

Throw a stock converter in there for 125.00 and go

I'd certainly consider it, but where do I find a stock converter for $125? Admittedly, I've been looking for parts for a 66 C6, which this clearly isn't. Still need to rebuild it with all the metal flake in the fluid.

No bubbles on the stick, and I don't know what servo is in it at the moment.

[fryedaddy]

i took my 66 c6 stock converter out and put a 3500 in.if you lived in east tn i would let you come get it free.dont want to ship,but if you lived close enough you could come get it.

[Gregwill16]

Dioceses not sure where you are located but I just pulled a 68 PI C6 from from 69 Mustang to go manual. Good ready to go transmission just bolt in and go for not a whole lot more money.

[Diogenes]

i took my 66 c6 stock converter out and put a 3500 in.if you lived in east tn i would let you come get it free.dont want to ship,but if you lived close enough you could come get it.

I appreciate the offer, but I'm a little up the road from you--NW Ohio, though I'm in Lexington, KY multiple times a week, still up the road a bit.

Dioceses not sure where you are located but I just pulled a 68 PI C6 from from 69 Mustang to go manual. Good ready to go transmission just bolt in and go for not a whole lot more money.

Let me know if I'm in your neck of the woods--please see above. I'm envious, I'd sure love to make the same conversion, but....

[Gregwill16]

I am only 15 minutes from Lexington in Winchester KY and don't mind to meet somewhere if needed.