Well, the C6 rebuild is going great. As user ‘9F91H581221’ put it, the C6 is a good one to learn on. I found that the Ford Service Manual has an excellent section on the transmissions, except for the pics. Rather than being able to swap assemblies, everything had to be rebuilt or checked, and you’ll see why…
One of the plans for my C6 was to install a ‘LOW GEAR/LOW DRAG UPGRADE’ kit which I had found from TCI, a large online Transmission supplier. The $750+ price tag was hard to get around. After some web surfing, I found a kit which has the ESSENTIALS from the TCI kit at a much better cost.
Now Daryl down at WCCC was curious about this low gear package, so this one is for you, D. Sorry it could not be shorter.
Oregon Performance Transmission (http://www.oregonperformancetransmission.com) is located in Salem, Oregon. They do not have a storefront, just a website and Ebay store. This allows them to keep prices low. Really low. Every upgrade kit or part I shopped they had, and at the best price. No phone support, and most of the stuff comes without instructions, but they are good at responding to email if you have questions.
Here is a link to the OPT kit, which sells for $275.99:
Given what you get for that, I think it is well worth it, especially for cars running low rear-end ratios like 3.25 and under.
The purpose of the kit, as OPT puts it, is:
" This kit will increase your acceleration without changing your rear-end gears. Lower 1st gear by 10% and 2nd by 5%. This set will work for all years. This kit will lower your 1st gear ratio to 2.71 from your stock 2.46. Second gear will be lowered to 1.53 from 1.46."
So I did the math on MY rear ratio to see what I was winding up with:
With the change in 1st gear ratio from 2.46 to 2.71:
2.71 x 3.25 = 2.46 x Y
2.71 x 3.25 /2.46 = 3.6 effective ratio in 1st gear (as compared to stock tranny ratios)
and in second from 1.46 to 1.53:
1.53 vs 1.46 2nd gear
1.53 x 3.25 / 1.46 = 3.4 effective ratio in 2nd gear (as compared to stock tranny ratios)
With the final drive staying at 3.25
Not much downside, except for an increase in RPM’s on the 3-2 downshift for passing. This may be too much for 3.5 and up rear ratio’s, but that matters more for street than strip I would think.
So below are the pics of the kit, and some pics showing why you want to beef up that tranny along with a motor upgrade, or face some ugly consequences.
Here in the layout of the sections inside the C6 case, the '73 stock unit is on the left, the '68 'rebuilt unit on the right:
The damaged parts you are about to see below are from the '68. Apparently the rebuild went as far as frictions, some seals, and shift kit. This, along with some abusive shifting by the PO, only served to over-stress the existing internals which carry most of the load.
The unboxing of the low gear set from Oregon Performance Transmission:
Below, the new steel 6-pinion planetary is on the right. Included with the kit is a low profile hub for the forward ring gear to accommodate the torrington bearing. This replaces the #5 thrust washer for less drag. Other thrusts will be replaced with the torrington bearing kit, also coming from OPT:
Also with the Low Gear kit comes a hardened sun shell. I did not appreciate the need for this until I removed the snap ring needed from the old unit.
This transmission was a few good romps from a catastrophic failure. The only thing holding the sun gear were teeth where the hub ring sheared away:
The over-run one way clutch in the rear had a few broken springs and was spitting rollers. The replacement from OPT gets installed without the snap rings (not shown):
The Lo-reverse and Forward clutch disks looked fine next to one from the stock '73:
The Direct clutch was a different story. These disks and steels are toast…literally:
Oregon Performance Transmission has an 8 disk replacement set with different steel thicknesses to beef up the holding power here.
This thrust washer had a good bit of debris in it at one point. Torrington bearings replace many of these with the kit from OPT.
Soda blast does a decent job on the case without risk of damaging debris littering your housing:
…and finally, a gratuitous shot of my ‘proper’ shift arm and Neutral Switch.
Being a column shift case, I had to drill and tap the holes for the switch, which I did right down the center of the spots made for it. HOWEVER the repro switch, when tightened down, would not allow the detent to fully fall into PARK. I had to oval out the holes on the switch to get it right.
Tomorrow the last parts from Oregon Performance Transmission will come in. In addition to the previously mentioned torrington bearing kit will be a 2 1/2" wider intermediate band (stock is about 2.1"), and those direct clutch disks and a new modulator.
Then I can bolt it all back together!