Hello everyone, I am having problems with my 91 F150 4.9L with a E4OD Transmission. When taking off from a stop, as well as when i slow down to make a turn onto a street the trans acts as if it is in the wrong gear and it slips (sometimes I get a grinding like noise and the truck shakes). The fluid is full but I will say it does need a change. I recently changed the Neutral Safety Switch because of a problem I was having when driving on the higway. It was basically jumping out of overdrive for no reason at all, and I read on this forum that that would fix the problem, and it did. But now I am faced with this situation of the slipping. It's almost as if it is low on fluid but it is not. Can anyone out there tell me what possibly could be wrong with my baby.... HELP PLEASE!!

 

It could be a million different things, however try changing the fluid in both the pan and converter. Use a quality fluid. I personally use Valvoline Maxlife. I tried some el cheapo fluids and my truck shifted as if the trans was going to die in any moment. I've found that high mileage ATFs are very stout.

 

Thank's, The trans has about 85,000 miles on it. You think High mileage fluid would be good in it?

 

Just out of curiosity it noticed you said drain fluid from pan and convertor. Is there a separate drain plug from the convertor?

 

I think there maybe on some converters. I havent checked mine to see if it did. Never the less I could just drop the pan and drain it. Now I heard that its not a good thing to change the filters on those trans, is that true, or should I go ahead and change it while i am under there?

 

While you have the pan off make note off how much debris is in the pan.[clutch and band lining material] this will give you an idea of the trans overall condition. the only way to drain the converter is to remove trans and dump it out this would be a good time to check all the adjustments also check the modulater valve I would definatly change the filter it could be restricting oil flow to the front pump besides you will get more of the old oil out you could also disconect the cooler lines and blow the oil in the cooler out. If there is alarge amount of friction material in the pan or it smells burnt its prbably time to start shopping for a trans. good luck Bubbabud

 

@buddabud...Thanks, You made a great point of checking the debris in the pan.. but just to make sure, i have the E4OD trans and las i checked there was no Modulator Vavle on that trans ( I could be wrong though)

 

My 1990 E4OD has a drain plug on the torque converter, so I'm sure this is the case on later model E4ODs.