Slipping when kicking down to passing gear?

93LINCMK8

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I'll try again, I had no replies last time.

The symptoms of my tranny did a 180. It used to shift irratically at low speeds and hit hard at WOT. Now it shifts normal at slow traffic speeds but seems to slip when kicking down and accelerating hard.

The change happened after I replaced the VB. What else could it be, besides maybe the TC clutches after only 30,000 miles?

I don't know how else to describe it.
 
I got the VB from Central Valve Bodies. It was listed as a 93-94, 13mm bolt, casting #F3, 1-3 ohm lock-up. I asked about the 1-2 and 2-3 accums. I don't think they did anything besides take them out and put them back in. I had them take them out while I was there. There was a bit of a pit in the wall of the 1-2 accum. I don't know how the accums. work but I found it wierd that there was no snap ring in the 2-3 accum and the manual didn't show one but there was a groove for one.

There was grit all over the casing. They figure maybe a poor cleaning job on the TC leaving sand or glass particles. They cleaned it the best they could with Kooler Klean. There were no chuncks of clutch that I could see.

Like I said, at light throttle it seems to shift correctly but at heavy throttle it revs high and then lurches into the next gear. Kinda opposite from before the exchange.

The spring in the 1-2 was pink and quite weak. I don't know how firm it should be. Are they color coded and if so what color should it be? Why is there no snap ring in the 2-3? It just kinda floats in there. I don't see what good it does like that.

I know I should probably put another tranny in there but I haven't got the money right now so I'm doing what I can. It just hasn't been right since the tranny was rebuilt 35,000 miles ago.

Here's a picture of the VB I purchased.
 

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Here is some stuff worth reading for you.
http://www.tccoa.com/articles/tranny/transmission/shiftybusiness.shtml

The sand or glass particles are actually aluminum casting material that means something is really been torn up, and is wearing excessively. From the info you've given it seems like finances are tight to do much so I would advise you to baby the car and keep away from the WOT stuff until you can afford to do a rebuild/replacement.
 
FYI - there is no snap ring for the 2-3 accumulator like the 1-2 accumulator has. The 2-3 accumulator cover has tabs that need tweaked to hold the cover in place in the groove that just looks like a snap ring groove.
 
Well, I doubt they were tweaked. I believe he just put a little grease to keep it until the VB was in place. I take it that's BAD. As a matter of fact, it came out pretty easy too so maybe it wasn't in right since the rebuild.
 
All it does is hold it in place until the valve body is on. The valve body then supports the cover which is then the base for the accumulator spring.

If you built the transmission outside the vehicle upside down, it wouldn't matter. :p
 
So I guess it's in there correctly but it doesn't make sense to me how it works just floating in there. Seems like there's almost 1/8 inch before the spring would do anything. Well, so much for that idea.

Now I'm still wondering why it revs so high going into gear at heavier throttle when it use to be nice and firm before the VB change.
 
I read that article Roadboss provided. What do the new type accum do better than the old. A better seal? Would they have anything to do with the apparent slipping when engaging gears?

I wish there were something I could read on the specific role of the parts, accumulators etc, and how they work and what the symptoms would be if they were faulty.
 
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The tranny tech articles on TCCoA pretty much tells you what you need to know.

I have the tranny manual(s) and have studied them some. From my experience and comprehension from reading, it sounds like your direct clutches are slipping. That could be from a myriad of reasons but likely due to pressure loss during the shift. If it 'feels' like it's slipping, trust me it is slipping bad!

Does the 1-2 shift and 2-3 shift feel and act the same? What does it do if you put it in manual 2nd?
 
Iv rebuilt motors, carbs, did body work and nearly everything there is to do to a car or truck but i fined its ALLWAYS BEST to take a trans to a shop and let a PRO do it. It’s the only part of a car I’ll say “pay to have it done.” You could make a small thing in to a major burn up of your trans if its not done right. now that the trans is slipping the dust turns in to an abrasive in the trans fluid and will destroy it. i just shelled out $2100 on mine and have no regrets. you may be able to get out for less that $200 if you dont mess around. every mile you drive is another doller in damages.
 
It shifts ok manually except for 2-1 shift. When you manually shift from 2-1 at 10 mph it slams into 1st hard. I noticed that it doesn't rev and lurch into gear everytime. From the TCCoA article I gather that I may have a direct or intermediate clutch problems but I hope that it is just leaking past the accumulators causing the loss of pressure at the time of shift. As I said, tha accumulators were not replaced and were kinda loose in the bore. I see how the new kind are better.
 
Cool. I'll check with my dealer here again. Last time they said they had the 1-2 but not the 2-3, and that was just looked up by the vehicle year and model. I'll try the specific part numbers.
 
Cool. I'll check with my dealer here again..

Do yourself a favor and call Max at www.fivestarford.com

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3. he supports the mark 8 owners very well.

We buy ALL our Dealer Specific parts from Max

Best part is.. there is no sales tax on internet sales unless you live in Arizona..
SO what you would pay for shipping, is offset by the lack of sales tax.

AND... Max will get you the hard to find parts that normal dealers wont trouble themselves to "look up".

give max a shout
 
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