Transmission Slipping Between 2nd and 3rd

Firminator_X · #1 (**permalink**) 06-30-2008, 09:48 PM

Hi everyone,
My wife has 1999 explorer V6 4x4. It has 96,xxx miles on it. It seems to have an issue shifting from 2nd to 3rd. When accelerating normally and shifting between 2nd and 3rd, the RPM's will rev a bit at which point the transmission will shift (snap almost) into 3rd. When accelerating harder the transmission seems to shift normally. Fluid level is ok. Am I looking at a rebuild?

I really appreciate this forum, you all have been a great help in the past!

srercrcr · #2 (**permalink**) 07-01-2008, 06:39 AM

Maintenance history? The fluid you're using?

Firminator_X · #3 (**permalink**) 07-01-2008, 11:16 AM

Well,
I haven't had the tranny flushed since I bought it about 4 years ago (roughly 35k miles). Because I haven't changed the fluid, I wouldn't know what is in it.

I can tell you that the fluid level is ok, still has good color and doesn't smell burnt.

If it was the fluid, why would it only slip between 2nd and 3rd?

Firminator_X · #4 (**permalink**) 07-01-2008, 12:17 PM

I just spoke to a local shop that thought this could be a bad Valve Body?

srercrcr · #5 (**permalink**) 07-01-2008, 12:39 PM

Since you know it's gone AT LEAST 35K with that fluid, and who know how many more, it needs it flushed at a minimum. I know the 2000 was spec'ed for Mercon V (perhaps the '99 also), the possibility it has something less in there is there.

Firminator_X · #6 (**permalink**) 07-01-2008, 01:10 PM

Thanks,
But again; why would it only be slipping between 2nd and 3rd if it was bad fluid?

srercrcr · #7 (**permalink**) 07-01-2008, 10:11 PM

What am I? An automotive engineer? I'm just a maintenance freak and learned a long time ago it will keep you out of trouble.

Firminator_X · #8 (**permalink**) 07-01-2008, 11:09 PM

Easy Steve,
I am not trying to question your intelligence. No doubt that routine maintenance keeps people out of trouble. However, this isn't the boat I am currently in. I thought my question was a valid one and would possibly get to gears turning and lead to more answers. Thanks for your attempt to help me.

spikedog · #9 (**permalink**) 07-02-2008, 10:18 AM

I'll jump in here. Does it shift the same way if you manually shift the tranny from 2 to 3 versus doing it all in drive? Where I'm headed here is maybe some linkage adjustments, rather than a tranny rebuild.

Sounds like the rig is still driveable, eh?

srercrcr · #10 (**permalink**) 07-02-2008, 10:52 AM

You might get some qualified help under the Transmission forum.

Bear River · #11 (**permalink**) 07-02-2008, 12:09 PM

Ok, the reason fluid can make a difference is because it is an engineered fluid with a delicate balnce of many different types of chemicals, including FRICTION MODIFIERS. As the fluid ages, the ratios of these compounds change, as do their chemical makeup. This alters the way they perform, which in turn can dramatically change the way the fluid behaves.

However, there is another side to this, and it has to so with friction material which wears off the bands. This material is relatively harmless so long as it stays in suspension. However, the fluid can only carry so much before it reaches saturation and cannot hold any more. This is why the fluid should be replaced about every 30,000 miles or so. Once the saturation point has been reached, this crud drops out of the fluid and becomes abrasive. It begins to eat away as the various moving parts, namely, the valve bores, the seals, the gears, and the remaining friction surfaces. The transmission basically begins to suffer accelerated wear.

There is a flaw in the 5R series transmissions, and it has to do with the side load on the solenoids that engage the bands. These engage at an angle, which applies pressure to one side of the shaft, which causes it to wear faster on one side. When it wears enough, it no longer applies full pressure to the bands, which in turn allows them to slip. Frequent fluid changes can reduce this type of wear, however in my opinion, this is a design flaw. The 5R transmissions are found in 2001 and newer Explorers and Rangers, but were found in some models as early as 1997.

85e150six4mtod · #12 (**permalink**) 07-02-2008, 02:36 PM

"Flaring" between shifts, which is what the OP describes, is a "feature" of these transmissions. My new-from-Ford under ESP warranty trans, with less than 5000 miles on it, does this.

It was reduced by a band adjustment and some Justice Brothers additive...not sure what variety of snake oil that was, but it seemed to help.

So, have a service, new fluid, shop for an additive, save up for the day it blows up completely.

There are two kinds of transmissions in these things. Those that have blown up, and those that are going to blow up.

BJWinter · #13 (**permalink**) 07-02-2008, 07:05 PM

Just to throw my two cents in, if you do have the fluid flushed beware the quick lube shops which hook it up to a machine, purge the fluid, and fill it back up. I've seen these knock crud loose which settles in the filter (which they do not change) and all sorts of problems follow because of the restriction it causes. Do yourself a favor and spend the extra 30 bucks to have a good shop change the fluid, filter, and gasket all at once. That 30 bucks could save you big money down the road.