Hi there,
last week I changed filter,fluid and rear main seal on my '91 F350 with the E4OD transmission hoping I would solve the leakage.
Last weekend we went to a horse show and we pulled our 4 horse gooseneck with 4 horses on it and all the tack.
Today I checked the seal and oil level and guess what.
Still leaking.
I had done a test drive before we went on show without the gooseneck and didn't see any leaks.
Can it have to do with the heavy pulling and is there a solution to this problem.

Thanks,
Johnny

 

Usually ATF leaks are caused by too much heat or old brittle seals.

If you have a tranny temp guage you should stay well below 210-220max and let the tranny cool down with engine idling before shutting off. A larger cooler may be needed. You really want the fluid to stay around 150-190 while moving at freeway speed.

If you fluid is normal temp, then you probably need a new seal. Did you say you replaced the rear seal? Usually it is the front main seal on the tranny that leaks. It will drop from the bell housing.

Good Luck,

Jim Henderson

 

Thanks for your reply Jim,
I don't have a temp gauge on the transmission but if I look at what I'm hauling it figures the temp will rise. First I will give the oilcooler another location, I found out it's not getting all the driving wind it could get.

And yes I replaced the rear seal because it was obvious it was leaking from that point. But if the leaking has to do with to high temps it's possible the old seal wasn't broken.

In my opinion the front seal isn't leaking that much, I have a drip of oil at the bellhousing but the bottom of the oilpan is still dry.

Can it help to make a breather so every sort of build up pressure can exit easily ?

Johnny

 

Keep in mind I am not a tranny mechanic, I just tow and got to pay for a couple trannies in my time.

Usually there is already a vent on the tranny.

I forget for sure, but I seem to recall a discussion on this website that said the leakage was thru the front seal due to high temperatures and high pump pressures. Mine dripped a couple times after a long hot haul at high speeds. The drip rate was maybe 1-2 drips every 5-10 seconds or so while sitting at idle in the driveway.

I have read about some trannies spitting atf out of the dipstick tube under high load at high temperatures, such as the Grapevien in Calif during the summer.

Normally this drip goes away after things cool down. Over time as the seal gets older and brittle, it will leak more often.

This is my experience and recollection from reading.

Jim Henderson

 

I decided to keep driving with the truck without adding oil. When I fill the tranny like the manual says it just throws out the oil when I ride with the gooseneck.
A friend of mine had some trouble with his truck and asked me to come and get his 6 horse gooseneck. Without refilling the tranny I hauled the 6 horse gooseneck including 6 horses and tack without the engine getting hot and without any leakage and still shifting good.

What should I do, just keep hauling and don't refill or id there a problem somebody knows of.

 

How low is the dipstick reading? Are you following the manual procedure to measure the level?

You have to follow the manual procedure almost to the letter or you can get incorrect results.

Must be level and not too hot not too cold and shift through the gears and wait at each gear etc.

If you are keeping fluid to the proper level and checking frequently and the fluid smells and looks OK, then you are probably OK. But a leak leaves little room for error. Leak too long before checking and you could fry the tranny.

What do you mean throwing the oil out? This sounds more serious than a drip. Is fluid getting thrown around the engine compartment or under the truck?

Jim Henderson

 

oops, I may heve filled mine wrong then, sorry havent got a book, anyone have the procedures handy. looking like I need a rear seal. Truthfully, it should have an entire service, filter, flush etc. gonna switch it all over to amsoil synthetic, tranny, engine, diffs etc. thanks! Dan