Aamco rebuild has problem. Help?

[StuartT]

I just picked up my 98 Explorer with a 5R55E transmission from Aamco, who rebuilt it. At speeds above 45mph or so and in high gear, if I step down on the gas to accelerate, but not enough to shift into passing gear, the transmission feels like it is jerking or slipping or shuddering, hard to put it into words. I don't know if these torque converters lock up, but struggling back and forth in and out of lock up would be my closest guess as to how it feels.

Have I described the symptoms well enough for anyone to help me figure out what is going on? I am not at all pleased with my Aamco experience and I want to be knowledgeable when I take it back.

 

[BrooklynBay]

Find out if they used Mercon V fluid with Lubegard friction modifier.

 

[StuartT]

Find out if they used Mercon V fluid with Lubegard friction modifier.

I finally found out that they used Dexcon III with Lube Guard. They claim that made the Dexcon III the same as Mercon V. Is this true or are they just cutting costs at my expense?

 

[BrooklynBay]

Mercon V cost considerably more. The fluid that was used is not designed for your transmission, and is known to cause slippage, shudder, and similar issues in late models transmissions such as your 5R55E. Lubegard could be added since it's a friction modifier, but the shop shouldn't try to cut cost.

 

[robrike40]

Stuart,
I had a very similair experience, almost to the letter, with my 97 Explorer with 5r55e. I had the 4.0 SOHC with auto, 4hi and 4 lo. My problem ended up being mismatched tires on front compared to rear. It would cause the transfer case to hiccup as I came close to but not dropping out of overdrive on acceleration. Check and see if the tires up front are same brand as ones on rear. If not, I would bet you mismatched size just from wear, not actual tire size is problem. Mine were same tire size all around but the fronts were different brand and tread wear depth than rear. When I ordered new tires all around I found my problem disappeared but not before a shop replaced the transfer case and u-joints with no resolution.
Check the tires and see what you find. Hope this helps, I fought this problem for a year and a half and $2k before I replaced tires and got a pleasant surprise to my problem.

Hope this helps,
Rob

 

[StuartT]

Thanks Mr. Moderator. It does look like a cost cutting tactic. I sent the following to Lubegard in Seattle this morning. I am going to make Aamco flush out the Dexcon III and replace with Mercon V if Lubegard responds as I think they will.

To Lubegard: I had my 1998 Ford Explorer 5E55R transmission rebuild by a shop and although the manual calls for Mercon V, they used Dexcon III with Lubegard Black HFM. They are telling me the HFM makes Dexcon III the same as Mercon V (blended ATF), but I can not substantiate that on any searches.

I am thinking they should have used Mercon V as specified by Ford and then added Lubegard Red as the preferred ATF, but I thought I would ask you folks first for some feedback.

Rob, I had all the tires installed new about 10K ago. Nothing has changed so I don't suspect a solution from them, but thanks for posting your experience.

Stuart

 

[StuartT]

Here is the response from Lubegard. If this is true, then Aamco may be correct in what they told me. I just have to verify the Lubegard product they added was the correct one.

Mr. Thornton,
Lubegard M-V ATF Supplement (black bottle, green cap) is the product that is
used to convert Dexron/Mercon into a Mercon V equivalent. The only other
product that is used for that application is the Lubegard Platinum
Universal. Are you sure that the HMF was used instead?
Best regards,


Elise Haviland x 10
International Lubricants Inc.
7930 Occidental South; Seattle WA 98108
T/206-762-5343 F/206-762-7989
http://www.Lubegard.com

 

[BrooklynBay]

Even though it appears to convert the fluid into Mercon V, it will not give it the properties of a real synthetic since it's not synthetic. The conversion might add the necessary friction modifiers to help prevent slippage, but that's about it.