just like the ***le says. how do i know if the transmission i have is good before i go through the trouble of putting it in the car? its a C6 if it matters.
About all you can do is check if the fluid looks or smells burnt and pull the pan to see if there is a lot of clutch material in it.
Short of taking it to a trans shop with a dyno, or taking it apart...nope. But more info might be helpful. Did you pull it out your self? What kind of shape was the car it came out of in? Is it complete with converter? How clean is it? Is it a leaker? Hows the fluid look? Did you check inside the pan for debris? Metal on the pan magnet? A C6 is a stout unit, but neglect will kill any trans.
Other than paying to have it run on a trans dyno there's not much you can do other than to install it and gamble a case of trans fluid along with a new filter and pan gasket on it. As already mentioned above, if it looks clean and doesn't stink of burned fluid then it's worth a try.
Flip a coin, that's a good way to tell. Seriously, either have someone that knows them look inside or install and try it.
I didn't bust mine all the way down, but since ANY trans should have at minimum a shift improver kit, i put one in. It's the only perf part i know that increases lifespan of the affected part (less slippage/heat). While i had the valvebody out, i used my chiltons to understand where the pressure ports were. Simple blowgun shots from my compressor allowed me to hear the servos apply on each port. I didn't tear it all the way apart to inspect the clutches, but i could see the front band and the fluid was cherry (and i knew the history of the vehicle it came from). This was on a 727, but do some research, and see what you can learn. Also PUT A KIT IN IT!!! even a mild one will help you tremendously.
When I had doubts about the integrity of a used automatic, I'd have it rebuilt by a shop, then install it. Most shops will let you bring in a loose one and will give a guarantee once its back in the car, bring it back and they look over the install and test drive it. I have had shops reseal them for me before I install them and toss in a new torque converter while I'm at it. Bob
I don't trust the idea of taking it to a shop with a dyno. Be careful who you deal with. I did that with my very first rebuild effort on a 700R4. I paid $75 for a dyno test for peace of mind. They said it would not shift into overdrive, and that I needed to pay them to tear into it and fix what I did wrong. At the time I had no money left for the project, and I really needed the pickup back on the road quickly. I decided to put it in anyway even if it did not have top gear because I needed the truck right away, and couldn't keep it down any longer like they wanted me to do. Well it worked perfectly, and I continue to use it almost daily today. That was 1988 and although I know it will someday need to be freshened up again, I will not pay any shop my hard earned money just so they can tell me to keep on giving them more money. I believe you will be better off in the long run buying a shop manual, learning the pressure-test points and the basics of checking it yourself. "hey, I'll pay you a hundred bucks to tell me to give you another thousand...."
Live a good life. Be nice to old ladies and little kids. If you keep a good balance in your karma account, you should be okay. If that doesn't work, get really good at swapping transmissions.
Put it in in test it yourself. Good practice, makes the day go quicker. Maybe you'll get lucky. If you take it to a shop to be tested it will need work for sure. They ain't in business to save you money. Paying somebody else is for stuff we can't do ourselves.
thanks for all the replys, folks. ive had this C6 sitting in my garage for about a year. its got fluid leaking up the side. yes i said leaking up. i dont understand it. its supposed to be a good ****** but it was tipped all sorts of upside down and around while loading for transport. will that hurt it? havent had the pan off yet. ill be checking for clutch material when i replace the filter. i was intending to install a shift kit so thatll be a good time for that too.
cant say for a C6 but going upside down wont hurt a mopar or chevy trans, so you're probably safe. leaking up is odd, is there maybe a crack that is weeping? how much fluid is in the darned thing? The only problem i can think of with being upside down and knocked around, is that it may have disturbed the sediment in the pan. Good to read for diagnosing wear, an even, thin layer is ok, but large piles indicate that the friction plates have been skinned pretty good. On Mopar trans you have to set one of the bands from inside the case, so get out your manual and tighten the band adjustments while it's on the bench.
I never pay more than core value for a used automatic transmission. And I never put a used one in a car unless I know it's history very well...even then I'll usually take it apart to reseal it
Okay, first of all, leaking up is probably due to case porosity or a very small crack. Secondly, what 69fury said is correct. You can pressure check the trans with shop air. That will tell you if the individual clutch packs engage properly. Pulling the filter won't really show you clutch material, unless it's catastrophic. The really small pieces are impossible to determine. Trans fluid color and smell will tell you alot, unless it was changed out after it was run in a vehicle.
I want to test the pump pressure on my, rebuilt with problems, 727. Is the front port the pressure side or vice versa? The trans slips between gear changes and just doesn't feel "hooked up". I think the TV linkage is okay as it will go up to a good speed between gears before shifting. I had the valve body out and checked, it is fine. This trans was rebuilt by a builder who does 'em everyday but this one isn't workin' so good. He said he put a new pump in it but it sure doesn't feel right. I R&Rd it to save $ and I'd rather not do that again -
rpm of the shift can be a function of governor action. The TV will add pressure to the shift, adding pressure as you give it the beans. "isn't working so good" and "doesn't feel right" aren't symptoms. Exactly what is it doing on the shift? Is there a flare? Is it firm? Quick?Slow?Long? I've never bothered putting a gauge on an exterior port for pressure, but i've run air through the case ports the the valvebody feeds to hear the clutches/servos. And run the pressure adjustment full up (allen wrench on side of vb-DONT go to far or it will fall out of the sheetmetal bracket and you get to pop it apart to put it back together) I also set the TV pretty deep to utilize the pressure that's available-maybe not the "proper" way but i set it fully in (minus a hair) at wot- basically all that can be dialed in without stacking up the linkage and lever. -rick
Thanks Rick - I think "flare might be a good term". You mean the RPM spike between geras? Yes it does that 1-2 and 2-3, sort of quick, but it's not right. Also on the take-off it seems to be slipping. The torque converter is a new one also. So do you put the air in the front port or rear?
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