What causes C4 to puke from dipstick tube

[ngsd]

Just installed this C4 in a 67 and while filling it and running it puked back up through the dipstick tube. After taking it for a drive it did the same thing. Level was OK, no water in it, dipstick was tight. Thinking a ventilation issue or? Any ideas?

 

[ared77]

I'm pretty sure this has been talked about on here before. Maybe somebody can find the old thread? I've got to leave for work or I'd look.

 

[Rustytruck]

The transfer case adapter has a vent on top its just a metal fitting with a loose cover like a small metal mushroom. usually when the tranny is upset it vents out of there I have never had or seen one puke up the filler tube. when cold and running the level is just on the tip of the dipstick c4 requires a hot check but the hot check is very hot not just warmed up.

 

[BanditBronco]

The only way I was ever able to get mine to stop blowing out the dipstick is to put a locking one on it. Mine would do it pulling off the freeway on the exit ramp. Mine was vented up to the top of the firewall as well. Best way to find out where it is happiest for me was to overfill it, then drive it till it stops coming out. If it is a street rig you won't have any issues running it 1/2 a quart low. For a wheeling rig, they like to be overfilled so you don't lose fluid to the pump when you are nosed up on a waterfall. Is it built with a shift kit etc?

 

[ngsd]

It did have a shift kit in it, The vent seems OK. I am not real familiar with C4's but is there possibly an issue with the line pressure check valve? When I fill it it takes forever for it to level out. The tube stays full and after it pukes then the dipstick does not read any fluid. It works fine except for the fluid issue.

 

[ared77]

Don't know if this will help any...but here is the previous link I was thinking of -

C4 Purged ATF or Mystery Leak

Bronco is back after a fresh 351w install and in the process of breaking in and road testing working out a few kinks. I made a trip to town and drove about 30 miles on that trip. When I got home and inspected I had ATF from front of main seal to the rear diff. It looked like someone squirted...

classicbroncos.com

 

[ngsd]

Don't know if this will help any...but here is the previous link I was thinking of -

C4 Purged ATF or Mystery Leak

Bronco is back after a fresh 351w install and in the process of breaking in and road testing working out a few kinks. I made a trip to town and drove about 30 miles on that trip. When I got home and inspected I had ATF from front of main seal to the rear diff. It looked like someone squirted...

classicbroncos.com

Thanks I did read that one. The curious part is that whether cold or hot the tube fills up and does not drain into the pan well and the whole dipstick shows fluid. When it eventually does drain, the dipstick will show low on fluid hot in neutral. Then after I drive it then it pukes. If I try to fill it overflows. I just ordered a locking dipstick but that wont cure the issue.

 

[gnpenning]

Is it a pan fill or case fill?

Did you or anyone else have the trans apart?

Any idea on how many quarts for the intial fill including torque converter?

 

[BanditBronco]

That was also my next question, case or pan fill? It took me about 6 hours to fill a pan fill from empty with the lokar dipstick. All the case fills I have had before never had that issue.

 

[Rustytruck]

if you added a external cooler make sure it is plumed to hold the fluid when the engine turned off. so you don't get drain back. I learned my lesson on that one when I plumbed my power steering cooler. turned my engine off and the drain back overflowed the pump resiviour and dumped a quart of power steering fluid on the floor.

 

[ngsd]

That was also my next question, case or pan fill? It took me about 6 hours to fill a pan fill from empty with the lokar dipstick. All the case fills I have had before never had that issue.

So I assume that you needed to add fluid and wait for it to drain into the trans? I added a pint last night and it filled up the tube, I was going to check to see tonight if it drained in.

 

[BanditBronco]

So I assume that you needed to add fluid and wait for it to drain into the trans? I added a pint last night and it filled up the tube, I was going to check to see tonight if it drained in.

Yeah that basically how it went. Make sure you are adding it while its running in park of course. I would fill it, jump in, cycle through all the gears and then see if it sucks it down.

 

[ngsd]

Yeah that basically how it went. Make sure you are adding it while its running in park of course. I would fill it, jump in, cycle through all the gears and then see if it sucks it down.

Funny enough I did that again and again and the level keeps rising!

 

[ngsd]

It is like it has a vapor lock or something. after it pukes out the level wont read anything but it doesn't lose more than a pint.

 

[Justafordguy]

Sounds like the vent is plugged up, no where for the air to go.

 

[ngsd]

Sounds like the vent is plugged up, no where for the air to go.

I have been thinking the same. I guess I will pry that cap off and see if it plugged and then try to put it back on. I have never tried it so any thoughts there?

 

[Rustytruck]

When I had my tranny out I pulled the vent out and threaded the vent hole to 1/8 pipe and ran a brass elbow with a compression fitting and ran a steel tube up the firewall and put the vent up there.. but my tranny and transfer case was out.

 

[ngsd]

Yes if it were out I would do that but as mentioned tapping while in would leave metal inside now.

 

[BanditBronco]

I forget, is that mushroom cap fitting pressed into the case? I wouldn't worry about prying that mushroom cap off, you can easily crimp it back on there with a pair of needle nose or something.

 

[Rustytruck]

Its been so long since I did it I don't know if it was threaded I know I tapped it to clock the elbow fitting. take your cellphone and take a picture and see if there are wrench flats on the bottom.