transmission fluid change

I always thought just dropping the fluid out of the pan was good enough. Is the fluid burnt? I'd be a bit worried running the tranny when it's that low on fluid even for a few seconds. I'd spend the $80-100 to get the whole system flushed if it's burnt otherwise I'd just drop whats in the pan and refill with the new gasket & filter.

Fluid is not burned, but old. More like 200+ extra to get it done.... If it were 80-100 to get it done I'd go for it, but they get too greedy and try to gouge too much so they lose my business. I just swapped out shocks, rear spring, new rad support, and rad myself for the same reason. I'd also pressure wash the pan and paint it etc, while I was doing it as well.

A local independent will do the work, flush the tranny and system with his state of the art equipment, for less than $150.

Is the flush necessary ---in most cases no, but if properly done it normally doesnt hurt anything and in some cases of problems it can work wonders.

You can change the fluid and filters yourself for a fraction of the above.

Do you have tranny problems, or just want to service the tranny?

Fluid is not burned, but old. More like 200+ extra to get it done.... If it were 80-100 to get it done I'd go for it, but they get too greedy and try to gouge too much so they lose my business. I just swapped out shocks, rear spring, new rad support, and rad myself for the same reason. I'd also pressure wash the pan and paint it etc, while I was doing it as well.

******* Find a GOOD local independent and get a quote. Dealerships can be very expensive and sometimes not very good

if you're going to try a DIY flush I would actually clean the pan first, reinstall with the OLD filter and gasket, flush, then put the new filter and gasket on. Flushing might put more gunk in the filter, why not get it squeaky clean. you will lose a little more fluid that way tho

nate

I agree, Nate, but if you are capable of dropping the pan and changing the fluid and filter, do you really need a flush (normally)?

IMO, flushes are not normally needed, but SOMETIMES they are.

The only tranny problem I have is that when the weather is quite cold, it will hesitate a bit before it actually takes off. Once going or once warm it is fine. The fluid has not been changed in a long while so I am catching up on some long overdue maintenance. I suspect a good cleaning, new filter and some good fluid will make it as good as gold.

.

That sounds like an option. I do not have to have it perfectly leak free just to circulate the fluid from the converter.....

Well, seeing as most people don't bother to change it every 50K like you're supposed to, I'm just ASSuming he needs a flush.

nate

The only tranny problem I have is that when the weather is quite cold, it will hesitate a bit before it actually takes off. Once going or once warm it is fine. The fluid has not been changed in a long while so I am catching up on some long overdue maintenance. I suspect a good cleaning, new filter and some good fluid will make it as good as gold.

********** Cold weather means that the fluid is more viscous than usual, or that the line pressure...to some degree controlled by the pump, is not enough to get the tranny working as it should.

A worn pump, or other things, can cause the line pressure to be insufficient to cause the slushbox to shift and hold.

Do the simple things first.. Replace the filter and change the fluid. If you get no relief, go deeper.

And, you may well have to go deeper in this case.

You can't see it from there, but I'm patting myself on the back for not poasting something like "who the hell buys a Corvette with an automatic, anyway?"

Oops...

nate

(seriously, I'm just giving you a hard time. But I know how you can never have to flush the transmission again...)

1976 may well be old enough that the torque converter -does- have a drain plug.

I don't think I'd try exactly this.

If there is someone else that can help you, have them keep adding fluid at about the same rate as it's coming out. Or, make up something like one of those 'radiator filler' funnels to keep the fluid flowing.

You really don't want to run a lot out, and a quart at a time...you got a Sunday and a 30 pack, right?

Or, drain and fill, drive 1,000 miles or so and do it again.

And in others it can screw a tranny up so much it's time to go to Cottman's,...

The other thing (although more of an issue for Chrysler trannies) is to make sure they use the right stuff! Chrysler trannies take ATF+3 or +4, they use "generic tranny fluid with 'friction modifiers'". Uh-Uh! My Chrysler tranny worked perfect, I wasn't about to mess that up!

I'd say just drop the pan, clean it, put in a new filter and just fill it back up. Sometimes when the fluid has not been changed in a while the flush seems to do more harm then good based on sporadic anecdotes. If the simple way works you can always do it again in a year and get more of the old fluid out.

well - on the basis of what I have read and inputs, I think I will adopt the drop the pan, drain, clean filter, button it up and fill, run, and drain again, then put on new gasket and filter, and refill. I will probably be too lazy to do it all again next year, so may as well try to do it well this time around. If I can find a big magnet to fix to the pan ahead of time to trap any debris I will do that too, and maybe swap out the modulator valve and the hose while I am at it. Just depends on my time.

The next item to be determined is: do I stick with the current Dexron III or move to something like a synthetic that are supposed to have superior properties?

What's the opinion on that one?

If you want to switch to a synthetic, you can't just do a drain-&-fill, as most of the old stuff is still in the torque converter. You will have to get all the old stuff out, which includes draining the torque converter. If you're lucky and there is a drain plug on the TQ, then you could do it after you drop the pan.

Still - with something that old, I'd be really hesitant to switch it to a synthetic. Much safer idea to just drain and fill several times, days or weeks between changes, until you get all the old oil switched out a little at a time.

r"

Good point - Dexron III has worked well all this time - maybe just stick with it. I did skim through the service manual and there is no mention of a drain plug on the TC, but that does not necessarily mean there is not one there I guess.

The next item to be determined is: do I stick with the current Dexron III or move to something like a synthetic that are supposed to have superior properties?

What's the opinion on that one?

************ I think you should just service the transmission, and not diddle with this double change strategy. When you service the tranny, you will find out whether or not a magnet is already in the pan. There might be one. If not you can get one from GM stock parts or a FLAPS and put it on the floor of the pan. They are shaped like large washers so they will lie flat and stay stuck to the pan. Dont experiment with Radio Shack or cow magnets.

Also, use what the manufacturer recommends as far as ATF. You run a risk if you switch to a synthetic on an old unit like this, even though it may be claimed to replace Dexron III. Dont fix something that isnt broken.