No idea how many miles are on the transmission, or if it's original or anything, but he van itself has 288,000 on it.

The transmission will not go into Overdrive at all, you can be going 65 and shift from OD to D and there is no change at all. so yeah it's not going into OD. When driving it at low speeds around town it feels as though it goes into Neutral when I let off of the gas, because it kind of "surges" when you get back into the gas. Just like you had shifted to neutral while coasting, and then shifed back to go again.

I think the "neutral" thing may be the TC not locking up, or maybe not... I am not a transmission person... The fluid is not looking good, the level is fine but it's brown. I will not change it period, I have seen cars not move again when that's been done. But then again I have seen Seafoam trans tune make a dead trans work again, so I dunno... Don't think I'm going to take any chances on this one though, as it is working for now.

My question is, is there any simple thing I can check that could be causing this problem? I have herd the OD band can be adjusted also, but have not done that before either. I think I herd there is a vaccum modulator on there that if it fails it wont go into OD, but I don't remember how to check that.

Or is it time for a new/rebuilt transmission?

Thanks for any Ideas....

-mike-

 

Hi Mike:

Welcome to our FTE forum

 

Mike,

If your ATF looks like chocolate milk instead of cough syrup, it is long overdue for replacement. A lot of folks here, including myself (and yourself apparently), have witnessed tremendous improvements in transmission performance after just a fluid change.

There have been stories of transmissions completely failing after a flush and fluid change, but the suspected cause for those is the reverse flushing action from those "power flush" machines pushing debris into tiny valve passages. If you do a manual flush, this should not happen. The guys here call it a "gentle flush", and it involves slowly replacing all the fluid 2 quarts at a time through the front cooling lines. There are variations on this, but you start by draining about 2 quarts of fluid from one of the front cooling lines with the engine idling. Then replace that fluid, and drive around a little, then repeat 4 times. Then drop the transmission pan to replace the filter, and top off the fluid again, and repeat the drain and fill one more time. The transmission capacity is about 10 quarts, and doing this 2 quarts at a time for 5 or 6 times will clean out MOST of the old fluid. And use a quality fluid, or better yet, a synthetic like Mobil 1.

Another simple check you can make is to see if the vacuum modulator is broken. There is a vacuum line that goes to the modulator on the passenger side of the transmission. It should be hiding behind a heat shield next to the catalytic converter. Pull the line to see if it has ATF in it; if so, you need to replace the modulator.

Some guys here have attempted band adjustments with disastrous results, so I would do that only as an absolute last resort.

 

I would get that fluid out of there now. It is true that some vehicles do have problems when the fluid gets changed, but the A4LD needs fluid changed every 30,000 miles. That old fluid looses it ability to lubricate, cool, and transfer motion when it gets so old. The seals shrink up, and everything dies if it is not changed. Everyone here does it. My old fluid was redish brown, and the van shifted at a higher RPM than it should have. New fluid filter, and a new transmission modualtor, and that thing runs like it was new.

I have seen the power flushes destroy trannies. My local transmission shop doesn't do that, that agree that the reverse flushing does no good, and can do a lot of harm. I would get the fluid changed by a reputable transmission shop, preferably one that is not a chain location, and have them gentle flush. I agree about the use of synthetic fluid, it lasts longer, protects better, works better in the cold, and stands a better chance or rejuvenating a worn tranny. If you opt to do it yourself, that can be even better, because you know it was done right.

 

3rd vote for
time to do a gentle flush and filter change now.....
replace vac. mod.