ATF, ATF everywhere

[smashingchuck]

Alright guys and gals, I've got a bit of a conundrum.

I put the 87 together about 6 months ago, but still haven't plated it for the the street. The trans (TH350, which was built new about 5 blocks away) has been rebuilt and has about 15 miles on it.

Here's what is happening. I put the trans pan on, and everything is fine. No leaks at all. I can go for a drive, and still no leaks. I can let the truck sit overnight, start it up, drive it, no leaks. but then after 2-3 days of the truck sitting, BAM, 3 quarts of ATF on my nice clean driveway. At first I thought the pan was the culprit, so I bought an aluminum pan that would not distort when i put the bolts in. I thought that fixed it until 3 days later there it was leaking again.

I can't really see where the hell it's leaking from... other than the pan area itself. my cooling lines appear to be tight.

Ideas?

[Jonboy]

It's probably the dipstick tube. The older ones just have an O-ring seal, and are prone to bending. The newer ones have a locking dipstick, and use a boot type seal at the case. The problem you are most likely having is the fluid draining out of the converter when it is setting. That raises the fluid level in the pan above the dipstick seal, and it leaks. The new tube, seal, and dipstick is less than $30 at the dealer.

[Slonaker]

I was able to get the seal for my dipstick at NAPA.

Slonaker

[87 STEPPER]

Have you spoke to the shop that built it and see what they say it might be?

The dip stick sound's like a good place to start tho ya may wanna look at the oring on the vac mod as well.
good luck

[smashingchuck]

Alright guys... I'll be getting a new dipstick. Any recommendations? I want to fix this problem for good, so if there is a better one out there, I'm all for it. Right now it's got an el-cheapo chrome one.

[Jonboy]

The cheap chrome one woul dbe my guess. You can try the boot seal on it to see if it will fix it. I had the same problem with my 75 Blazer after putting a rebuilt trans in. Replacing the tube, stick, and seal worked for me.

[3r!c84]

the shifter seall..mine has the same problem..have not changed it out yet.you have to drop the pan and pull out the shifter rod and slid in the new seal..but mine is only a few drops a day not no 3qts

[powerdriver 1958]

you did say its a 350 so another spot to check it the kick down cable.some have o rings some have a seal either will leak

[bagged74]

Originally Posted by Jonboy

It's probably the dipstick tube. The older ones just have an O-ring seal, and are prone to bending. The newer ones have a locking dipstick, and use a boot type seal at the case. The problem you are most likely having is the fluid draining out of the converter when it is setting. That raises the fluid level in the pan above the dipstick seal, and it leaks. The new tube, seal, and dipstick is less than $30 at the dealer.

this is my guess as well