Thread: 700R4 fluid level

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I swapped out my M-21 4 spd for a 700R4. It's a shoulder and age issue. Anyway, I routed the cooler, a B&M 14000 BTU, in front of the radiator. The lines run up over the right front fender and down to the cooler. Everything seems to be ok but checking the fluid level is confusing. When the fluid is cold, the dip stick shows the level to be way too high. I assume this is because the lines and cooler are higher than the sump and the fluid weeps down into the trans case. When the fluid is hot, the dip stick only shows fluid at the tip of the dip stick. Now here's the question: I think I should add fluid while the car is hot, engine running until the level shows it to be at the full position on the dip stick and forget about what the cold level shows or is there some other point I should be concerned with? The car shifts from first to second ok, but the 2nd to 3rd is soft. Any thoughts?

Assuming that you have a 700R4 dipstick assembly in it, adjust the level with fluid warmed up to operating temperature, idling in neutral, to the "full" mark and ignore what it shows you cold. Once you get the level right you could make a little tick mark on the stick with it totally cooled off if you want the peace of mind checking it cold, but running warm is the gospel.

thanks for the advice

We put the trans in, added the 10 quarts of fluid
and put the car on the road. BUT, we didn't calculate the capacity of the cooler into the needs of the system. I looked and looked on line but couldn't find the fluid capacity of the cooler, so I called B&M this morning. They said about 1 1/2 quart capacity for the cooler. The fluid weeps back into the sump when the car sits because the cooler is higher than the trans as are the lines. That would explain why at temp the fluid appears low and at cold, rest it shows high. Now here's the rub. As we discussed it, the tech rep said that we should try to keep the fluid level below max even at cold because overfill at cold will cause foaming in the fluid that will cause sloppy shifts. And, I'm having some sloppy shifts.

If this is the case, I still need to add fluid and lower the cooler. Noodle on this and let me know what you think.

Not to confuse you any but the level should be checked with engine running in neutral and level. Reason, not running as you say fluid comes back to pan, NOT only from cooler but from converter. Always check running, and level. Don't worry about where its at cold. Been doing it that way for over 50 years and no problems.

I agree, the pump fills the lines & cooler, and they're not going to drain back unless you've got a leak at a high point to let air back in. Fill it warm like Charlie says, and forget about it. If you've got sloppy shifts the problem is not cold fluid level.

Most automatics have it written right on the dipstick...........check in neutral.............or check in park.........and make sure it's up to temp.

First of all, welcome to CHR captnmike! Hope your stay here is long and that you find lots of good advice as well as share your own stories. If your avatar is the car in question the ‘66/67 Chevelle is one of my all-time favorites and your’s looks to be a sweet ride.

I absolutely concur with others that level should be checked in neutral and warm but also agree with B&M, re; sloppy shifts due to foam. As set up, the fluid drains to the transmission and the cooler when cooling off and leaves air in both lines. Until the air is completely purged and there is an uninterrupted flow of fluid from the transmission to cooler and back to the transmission you will have foam and poor transmission performance.

Heat kills automatic transmissions. The fluid is a much better means of dissipating this heat than air. Air and foam, even for a few minutes, can lead to problems in your transmission and shorten the usuful life of the clutches. If this were mine, I’d be tempted to re-plumb the cooler. In front of the radiator is the right spot for the cooler, but I believe that if you were to construct new lines from braided stainless lines using AN fittings and run them along the frame rail it would take care of your issue. Braided stainless gives you lots of flexibility and looks great too. That way, there would be no “up-and-over” for the fluid and you could do +/- 11-1/2 quarts and know that the fluid level would be correct.

Once again, welcome and let us know what you decide.
Glenn

Thanks for all of the great advice. The more I thought about the closed system, the more I realized there would be a vacuum lock preventing the fluid from back filling. But, to be on the safe side, I'm going to put on a slightly larger pan to accommodate a little more trans fluid and stop worrying about my handiwork. In the middle of this change, I tore my rotator cuff and let some good friends finish the job. Me being me, wants to go over everything to insure it doesn't end up on the side of the road at midnight in the Arizona desert. Thanks again for all the positive feedback. Once again this proves that Hot Rodder's don't leave one of their on on the side of the road. I owe you all a beer!

Originally Posted by captnmike50

Thanks for all of the great advice. The more I thought about the closed system, the more I realized there would be a vacuum lock preventing the fluid from back filling. But, to be on the safe side, I'm going to put on a slightly larger pan to accommodate a little more trans fluid and stop worrying about my handiwork. In the middle of this change, I tore my rotator cuff and let some good friends finish the job. Me being me, wants to go over everything to insure it doesn't end up on the side of the road at midnight in the Arizona desert. Thanks again for all the positive feedback. Once again this proves that Hot Rodder's don't leave one of their on on the side of the road. I owe you all a beer!

Forgot to also mention that I will purge the system of air to insure proper cooling. Mike