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Trans issue

NYC Bronco

Full Member
Joined
Feb 21, 2017
Messages
169
My '76 (302, C4 Auto) is acting strange. I had is parked on a slight incline (nose down) for two months and the trans seemed to leak out its fluid. I moved to a flat surface and added a quart plus most of a bottle of Lucas Trans stop leak and the issues seems to have gone away however.....when in drive and pressing the accelerator It seems to lose power, like the trans is dropping out of 1st and it revs up before 2nd gear comes in. it seems fine in 3rd at higher speeds (40-50 mph).

any ideas? I know it's brutal to triage this over the 'net.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
It sounds like it might still be low on fluid. Did you re-verify it was topped off after that last fill?

Paul
 
OP
OP
N

NYC Bronco

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Joined
Feb 21, 2017
Messages
169
Front pump seal leaking?

Could have been, I wasn't able to diagnose as the Bronco was parked at my house that was under renovation and at the time, I was living in another town. There is no leaking now
 
OP
OP
N

NYC Bronco

Full Member
Joined
Feb 21, 2017
Messages
169
It sounds like it might still be low on fluid. Did you re-verify it was topped off after that last fill?

Paul

pleading ignorance here, how many quarts or rather how fluid does it take?

edit: seems the C4 can hold about 8-10 quarts. I'll add some more and re-evaluate. the Bronco sat for two months and I was not at the property to check it so I don't know when the leak started and ended so it's hard to gauge. Won't happen again as I now live at the property and my green baby sleeps in the garage.
 

76YETI

Contributor
Sr. Member
Joined
May 27, 2015
Messages
856
Loc.
KC METRO
Mine leaks sporadically....I’ve read a lot about them and most say the c4 just leaks
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
NYC Bronco, do you know how to check the fluid level on an automatic tranny?
The tranny needs to be up to operating temperature.
While the engine is running at idle, run the shifter through all the gears.
With the tranny in park, and the engine still running, pull the dipstick.
Wipe the dipstick off on a rag.
Re-dip the dipstick and pull it back out.
Now you can read the dip-stick.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
Adding a random amount of fluid is bad. Overfilled is worse then running low.
Check the fluid level before just adding fluid. As mentioned, with the engine running. It will not be accurate if the engine isn't running.

The catch 22 is getting a transmission warmed up that doesn't have the correct fluid level in it. I know my C6 has both cold and hot ranges marked on the stick, they overlap. The top side of cold is in the same range as the low side of hot. So if you are at least on the bottom of the stick (usually with a "do not drive" mark down lower) get it up into the "cold" range with it running. Warming the transmission isn't the same as warming the engine. You actually have to drive and put some load on the torque convertor and transmission to warm it up. Sitting and idling won't do it. Well after 3 or 4 hours it might be close. Or 10 miles of driving will have it there.

No matter what, pull the dipstick and read the markings on both sides of it. That will tell you a lot. With the engine running, check it.
 

1buckeyefan1

Contributor
Sr. Member
Joined
Sep 21, 2017
Messages
629
Not trying to thread hijack, but I suspect my 74 w/ C4 is doing the same. Mine has sat for nearly 8 months now (undergoing a full facelift) and I swear the other day it 'burped' up a couple of ounces. I heard a fluid noise and had a fresh puddle underneath. I swear I saw a thread about this months ago, but can't seem to find it.
 
OP
OP
N

NYC Bronco

Full Member
Joined
Feb 21, 2017
Messages
169
Adding a random amount of fluid is bad. Overfilled is worse then running low.
Check the fluid level before just adding fluid. As mentioned, with the engine running. It will not be accurate if the engine isn't running.

The catch 22 is getting a transmission warmed up that doesn't have the correct fluid level in it. I know my C6 has both cold and hot ranges marked on the stick, they overlap. The top side of cold is in the same range as the low side of hot. So if you are at least on the bottom of the stick (usually with a "do not drive" mark down lower) get it up into the "cold" range with it running. Warming the transmission isn't the same as warming the engine. You actually have to drive and put some load on the torque convertor and transmission to warm it up. Sitting and idling won't do it. Well after 3 or 4 hours it might be close. Or 10 miles of driving will have it there.

No matter what, pull the dipstick and read the markings on both sides of it. That will tell you a lot. With the engine running, check it.

I would not call it a random amount. I think a significant amount drained out. When this happened and I tried to drive from one part of my drive way (up on the circle drive) down into the street and then up the flat driveway part to the garage it did not want to engage after shifting into any gears (R, N, D, 2, 1). I added almost a bottle of Lucas Trans Fix and a Quart of ATF. AS I said, it shifts fine and engages into the gears fine, it "feels" the way it has regularly felt engaging a gear it's just that while in drive and as it goes from first to second I get that point where if feels like it loses power and the engine is revving up before it goes into second. doesn't jerk into second, it catches smoothly but there is a definitely a gap.
 

Mikesimp70

Full Member
Joined
Jun 20, 2017
Messages
341
Sounds like you are still low on fluid. Start it up, shift fwd to reverse to fwd 4 or 5 tomes, put in park and check fluid level. Where is it on the dipstick?
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
IF you are not checking the level on the dipstick, it is still a random amount. Well you know what you added, but don't now what was missing. So it is still a random level in the transmission, not a known level.
 

Pa PITT

Contributor
Bronco Guru
Joined
Jul 15, 2005
Messages
11,252
Loc.
Stephenville TEXAS
Since I had my parts store back when these thing were new .. I saw a lot of these C4's overhauled.
.. When these were new they used Type F fluid .. Most after the overhaul used Dextron fluid in later years. But they sure didn't need the fluids mixed.
... Some of you other Guys that know these fluids chime in. That'S me remembering 40 years BACK.
...........
... A 2nd NOTE than never seems to get mentioned here durning these kinds of discussings .. When overhauling these trans ... It was very difficult to get the internal parts clean. The Valve body would always have sticking valves in it . One grain of dust or grim & It would not shift . Our town tranny man would go to the FORD House & help the Ford trans tech trouble shoot & Vise versa . We had 3 guys that we're really good at these & I sold a lot of kits
I hope those thoughts help slightly.
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,316
I've rebuilt a lot of C4s. None of them had exotic clutches that required anything other than type F fluid. You can't buy an overhaul kit with clutches that have anything other than stock paper clutches. I don't understand why people think a rebuilt C4 needs something other than type F.
 
OP
OP
N

NYC Bronco

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Joined
Feb 21, 2017
Messages
169
IF you are not checking the level on the dipstick, it is still a random amount. Well you know what you added, but don't now what was missing. So it is still a random level in the transmission, not a known level.

Yes I'm checking with the dipstick and yes it's low and reads "Add". It's still leaking so I'm going to take it to a trans shop.
 
OP
OP
N

NYC Bronco

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Joined
Feb 21, 2017
Messages
169
Modulator is kaput, seems that the PO was running some rubber lines where perhaps metal would have been better and they corroded and causing some of leaks along with a bad seal. Thats the initial news from the trans shop. the PO also used some Epoxy/JB Weld) type material to seal up a leak on the rear diff housing. gonna pull that down, clean it up and see of it can be welded from the outside or of the who thing needs to be opened up, cleaned up and welded from both sides. good times!
 

DirtDonk

Contributor
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Nov 3, 2003
Messages
47,355
Well at least it's good to start finding culprits. Although you can certainly do without new ones!
The leaky rear housings was actually a common thing. Not so common it ever made the 6 o'clock news, but something that people found over the years when they had little drip puddles in their garages over the years.

Epoxy was probably an accepted practice. But welding was definitely the preferred method.
It can be done with everything assembled too. Not sure of the steps, other than clean it, clean it, then clean it some more, but others here will know for sure.

Good luck.

Paul
 
OP
OP
N

NYC Bronco

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Feb 21, 2017
Messages
169
Epoxy was probably an accepted practice. But welding was definitely the preferred method.
It can be done with everything assembled too. Not sure of the steps, other than clean it, clean it, then clean it some more, but others here will know for sure.

I've been tracking this issue for about six months and I''m missing the rubber pressure valve tube, not that this would solve it. My guys is going to do just what you said, clean the shit off it, dry it, see what's what and then weld.

I think what I'm doing is the only option for keeping the C4. I could go for a newer Trans but that another can of worms and I don't want to do that while I'm still running the original 302. If and when I go for a new motor, then I'll re-evaluate updating the entire drive train.
 
OP
OP
N

NYC Bronco

Full Member
Joined
Feb 21, 2017
Messages
169
Epoxy was probably an accepted practice. But welding was definitely the preferred method.
It can be done with everything assembled too. Not sure of the steps, other than clean it, clean it, then clean it some more, but others here will know for sure.

I've been tracking this issue for about six months and I''m missing the rubber pressure valve tube, not that this would solve it. My guys is going to do just what you said, clean the shit off it, dry it, see what's what and then weld.

I think what I'm doing is the only option for keeping the C4. I could go for a newer Trans but that another can of worms and I don't want to do that while I'm still running the original 302. If and when I go for a new motor, then I'll re-evaluate updating the entire drive train.
 
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