My friend has a 2008 F150, 4.6L, 2wd, with only 84,000 miles on it... It had a cracked intake manifold (under the crossover), and the coolant leak fouled one of the coils a while ago. We replaced that coil and everything was ok for a while, but then it started happening again. So he took it to the dealer to have the intake replaced.

On the way home from the dealer, the truck was running worse than ever. He described it as "puttering", and he couldn't even maintain highway speed...

I think his transmission has coolant in it.

He took me for a test drive yesterday and it seems like the trans is slipping quite a bit... it "clunks" sometimes, when going from neutral to first gear, and shifting from first to second is a little weird too... There's also a subtle "whirring" sound, and it reminds me of when I had the same issue on my '98.

fwiw, I think he has the 4r75e trans... Code "Q".

The trans was acting up a little bit before going to the shop, but it was very subtle from what I'm told. We checked the fluid about a month ago and it was at the bottom end of the crosshatched range, so we didn't add any... Yesterday, after the test drive, the ATF level looked very high and there were some bubbles. Not foamy, just some big air bubbles.

When the dealer was doing the job, one of the first things they did was a pressure test on the cooling system. They did it to confirm the leak, and then they went ahead with replacing the intake.

My thought is; the pressure test caused something to fail inside the radiator and now coolant is getting into the trans.

I'm hoping I'm wrong, but I had the same issue with my '98... The radiator failed and let coolant into the trans. But when it happened to mine, the coolant in the radiator looked like "strawberry milkshake". My friend's '08 doesn't look that bad. (yet?)

I'm curious to see what everyone thinks.
Are there any other "known issues" with the 4r75e trans?

Thanks in advance,

Jim

 

I doubt a pressure test of the radiator caused a leak into the transmission cooler,but there could have already been one there.

I cut the rest of it because I may have been applying something I learned from a totally different transmission. My bad if so..

 

The tranny fluid level will rise and fall depending on how hot it is. So make sure the tranny is at normal operating temperature when checking the level. What color was the fluid?

 

The main cause of transmission fluid in radiator is a bad radiator . same for coolant in trans fluid/ I have helped on those failures . When buying radiator you must match up exactly your trans line hookup to existing . Many people order the wrong radiator or one without trans cooler in it. Can you bypass transline from radiator --no terrible idea in fact if you don't have a good extra trans cooler in front of radiator its good to install one . Heat kills tranny . Esp towing .

 

That's not accurate. The pressure in the trans cooler lines varies quite a bit due to trans type, temperature, engine speed, etc, but it can be around 30 PSI. That's about twice the pressure in the radiator.

 

I'll let it go.

 

I have. When I was running cooling tests I would also have pressure sensors in the cooling lines. 30 PSI wasn't uncommon.

In later transmissions, such as the 5R110W, 60 PSI is common.

 

Thanks for all the responses you guys.

My friend's 2008 has the double core radiator, and there's a separate, smaller unit down low in front of it. I didn't look close, but I'm guessing it's an oil cooler? Since the truck only has 84K on it, I'm guessing it's the original radiator...

Maybe I'm jumping to conclusions because I had this issue with my 1998 a few years ago. I was running straight water in the radiator and she overheated one day... When I opened the reservoir, it was all pink and foamy... shortly after that, the trans went out.

 

I was thinking about something like that, just as a temporary measure...

Since my friend doesn't do any towing, I was thinking about just attaching the two lines together, and bypassing the radiator altogether. "Just for now"...

I keep hoping I'm wrong, but this is a bad sign imo..

Even if it IS just the radiator, and we replace it... I'm wondering how much damage has already been done to the trans...And if a fluid swap would save it..

 

If anything, the fluid looks too light. It's nice and pink, but it looks watery to my eye. (Fwiw, the engine coolant has a light golden color, not green).

I keep wanting to think we made a mistake when we checked it, but I don't think so... We drove a couple miles, with some hills and a little bit of highway, and the engine was fully warmed up according to the gage. The ground was level enough, and we checked it in park with the engine still running. ... The dipstick showed the level to be very high, maybe two or three inches, and there were some big air bubbles on it. When we checked it again with the engine off, there was no more bubbles.

 

Yes the trans runs higher pressure so usually the first indication is trans fluid in radiator water . Radiators are cheap online . Get a new one fast ,change all trans fluid out using about 20 quarts over a few days ,it helps if you put a after market trans drain pan . No don't bypass .
The cooler you see behind radiator is power steering cooler .
The only hope you have is to flush tranny quickly and hope for the best . never run straight water with corrosion protection / my step son did and water turned to mud /rust and ruined the engine . make your coolant with distilled water from wally world.

 

When the fluid is too high the internal moving parts churn the fluid and that's what causes the air bubbles and sometimes a foamy look.

 

normally if the trans cooler tubes in the radiator fail, the oil will enter the radiator since the oil pressure is much higher than the 14 psi coolant pressure............ when the motor shuts off and you have no transmission pressure, it is POSSIBLE that the coolant at 14 psi could get into the trans oil... Normally you don't see much of that or to a much lesser degree than oil in the radiator, but it is POSSIBLE.

 

Thanks again for all the responses you guys...

I just did a search, and I found a product that can test for coolant in the ATF.

I also found a site that says even a little water is bad because "...the transmission clutches are hygroscopic; that is, they want to absorb water. They’ll even push ATF out of the clutch lining to absorb water". (But that was on an Audi).

Anyways, I called the local mom and pop shop that rebuilt mine, and he told me a simple test to check for water in the ATF. He said to draw some out, put it in a can, and heat it... If it "pops", then that means there's water in there... water boils before oil..

 

It's true on a Ford, too, and I suspect all other makes as well.