Hi...I hope you aren't getting sick of me, lol, but we just can't get a break lately with this van.
Last week, hubby retarded the timing, which eliminated the spark knock problem. Van was running good. This week, I thought the trans was going on me...when I put it into reverse, it didn't want to move well down the driveway, kind of felt like the brakes were on/jerky as it moved.
Once it warms up (like being driven for a few miles), the problem goes away. We changed the vac modulator yesterday, but no difference.
At first I was thinking trans problem, but this morning I thought...well, it is going immediately into gear when I shift into reverse, it is when I give it gas to move backwards that it gets all jerky...maybe this is an engine issue, not a trans issue?? Could retarding the timing make it drive 'jerky' in reverse? I am so confused, this one is harder to research and I'm coming up with nothing. Any ideas?
Thanks once again, Judy

 

Well, here is where I would start on this issue. Do you know the transmissions history? I'm assuming that you either bought the van used, or maybe you've had it for a little while now. The A4LD based transmissions in these vans are very picky about the quality and condition of the trans fluid.

There is a sticky on the subject of how to do a gentle flush, also called a dynamic fluid exchange. It is a method by which all of the old fluid can be removed from the transmission, the torque converter, and the cooler lines. This method allows a complete replacement of all the fluid without the dangers of a professional flush machine. The method is called a gentle flush because it uses the vehicles own internal pump to complete the process. Nothing will happen that does not occur under normal operating conditions. Please read the sticky, you can print it out and show it to your husband. This method does not need to be done on every fluid change, but it should be done if the maintenance history is unknown, or if the fluid is no longer red, but brown or black.

This will address the possibility it could be a trans issue.

Also, what tools did your husband use to set the timing? There are specialized tools for this purpose.

The first thing you need is a timing light. You also need to remove the timing plug, correctly known as the SPOUT plug. This is located on the main harness along the firewall. It is just a grey or black plug inserted into a connector. This must be removed when setting the timing. The timing must be set to 10 degrees before top center. To make the timing marks easier to see, you can rub some white chalk into the marks. You then use the timing light to line up the marks. At this point the distributor would be loosened. It just gets rotated till the 10 degree mark lines up. Then tighten the distributor, and verify the timing has not changed. It need to be on 10 degrees exactly. Once that has been correctly adjusted, the SPOUT plug needs to be reinserted. Make sure you run 87 octane fuel. Running higher can cause carbon build up in the engine, and lower can cause pinging. Running one rating higher won't hurt anything, but don't run any higher than 89. If you husband is certain that the timing is set correctly, then you can leave that alone, but it probably wouldn't hurt for him to check it again.

 

Thanks, I'll check all of that with hubby.

Here's another thought: once the car has driven a couple of miles, the trans works smoothly in reverse again...when cold, it acts like theres no fluid, which got me to thinking: we used Lucas stop leak in it last month, not a whole container, just some of it. A few days ago, hubby added more of it. It is thick, and may not move through the trans until it is warm....can you add too much stop leak to a trans? The bottle said to add the whole thing, which we didn't do at first. Hubby doesn't think this is the problem, but I've read it can clog the filter. What do you think?

 

not anything I would put in my automatic transmissions. Never been impressed with Lucas products.
only thing I would put in one of these Ford A4LDs is good brand name Mercon or Mobil 1 Synthetic ATF and Lubeguard Red transmission additive.

used the Mobil 1 Syn ATF in my Aero but I used to tow heavy 4500lbs. with it, over 40k miles just towing. over 170k miles , original tranny, still shifts like new. added plate cooler.

I would do the flush as suggested by khan. I run 14>16 quarts in to finally get all the old burned particle contaminated blacked dark stuff out. change the pan filter out first and clean pan and magnet.

just did the flush on the wife's Honda CRV, worst rig I've ever seen for ruining ATF. have to flush change every 30000 or it's the worst roughest shifting auto, miserable to drive until I change the ATF.