5.0L Tranny Problem?

[SR77]

I have a 1996 Explorer 5.0L AWD with the AODEW 4r70w 4-speed tranny in it. My problem is that when I am accelerating in 3rd gear about half way through 3rd the truck will drop like 500 RPMs and then continue to accelerate theought the gear and shift into 4th. It is almost like the tranny shifts half way through 3rd and acts like a 5 speed tranny but I have the 4r70w 4-speed tranny. What could be wrong? If it was slipping and I was accelerating the RPMS' would rise not drop, so I don't have a clue what it could be. I am thinking about taking it to Aamco or Cottman, but wanted to see what anyone on here thought it could be first so i could go there with some knowledge about it. Thanks for the help

 

[RiverRat]

Maybe you are feeling the converter lock up in 3rd (drive) and that explains the engine rpm drop and vehicle speed increase.

 

[Racin Jason]

The converter will lock up in 3rd an 4th gears. This is normal. You should see about a 200rpm drop each time it locks up. If you listen carefully you should hear the tranmission shift into 2nd then into 3rd then the converter locks in 3rd then shifts into 4th and then the converter locks in 4th.

 

[SR77]

Thanks for the replys. How do i know then if there is a problem with the tranny or it is just the TC locking up? I have never noticed this RPM drop in 4th, I have only noticed it in 3rd. Most of the time depending on how hard I am accelerating is how much I can watch the RPM's on the tach drop. If I am accelerating hard then there is less of a drop in RPM's, if i am accelerating normally or not aggressively, the more I see a Drop in RPM's. Is there a way for me to tell if this is just the TC locking up or if there is a problem with the tranny staying in 3rd? Is a 250-500 RPM drop normal when the TC locks up for those of you who experience this too? Like I said before it sometimes almost feels like a 5-speed tranny. Could it maybe be the TC slipping since I really only notice this in 3rd? I am glad I posted this here first before I went to Aamco and looked like a fool. Thanks again for all your guys help.

 

[Bill Kemp]

It all sounds normal to me also.
Since you didnt mention it I assume that you havent changed your trans filter in awhile.
Now that you have the trans on your mind its probably a good time to do that. A regular change on a veh. that age is good preventative maint. and will help keep you from the clutches of AAMCO. Cause you never get out of there for free.

 

[Racin Jason]

You are less likely to notice the lock up under harder excelleration due to the increased line pressure holding off the lock up function. You will usually notice it more under moderate excelleration. Under full trottle I don't think the lock function is felt at all. One way I can notice the lock up functioning in 4th is to lightly increase the throttle up a fairly steep hill. You should feel the tranny kick out of lock up giving about a 2-300 rpm increase after you feel that you can then click the overdrive off and see an additional increase (when the trans shifts into 3rd). If you do not see an additional increase when shutting off the overdrive, then the lock up function is either slipping or not working at all ( then the first increase you felt was the trans shifting into 3rd and not the lock up disengaging). The lock portion of your TC is actually a small clutch disc in the front portion of the TC which is activated by governer pressure. When you are in 3rd or 4th fluid is routed to the lock up portion and once the line pressure drops below a fixed psi the clutch then activates.

 

[MR BOND]

To answer your question about how to know If there is a problem with your transmission, your OD light will more than likely or should flash.

 

[SR77]

Thanks again for the replys. That is good news, I thought there might be something wrong but it sounds like it is just the TC locking up. I will try what Racin Jason says to check its function and hope that it is not slipping. I just did have the trans completly flushed including the TC and filter with Mercon V when it was at Ford getting some other things done. The funny thing is that I mentioned to the dealer what was happening and not once did they say it was just the TC locking up. Shows how much they really know. Thats why this site is so great, you guys just saved me the hassle and money it would have cost to go back to the dealer or Aamco for nothing. Thanks again for all the help