A4LD low/reverse servo question.

[pdknz]

Hi all--

I signed onto this forum weeks ago, as I was planning this job sometime last summer. The software this time told me it was time to post something, and I need a little help and moral support anyway, so here's another intro.

My name is Phil Koontz, and I live in Galena, Alaska. We are way off the road system, between Fairbanks and Nome, on the north bank of the Yukon River. The arctic circle is about 100 miles that-a-way, the temperature this morning is about -15, and there is a foot of snow on the ground. My '91 Aerostar has an A4LD with full time four wheel drive, and the main problem seems to be the classic low-reverse servo symptoms--it will back out of the driveway, but it won't move in OD, and the forward engagement in D takes sometimes as long as 30 seconds, especially first thing in the morning. I have it up on jackstands in a heated shop, and the tranny pan and valve body are already out of it. My plan is to do a valve body job, plus everything else I can fix or mess with while the tranny is in the vehicle.

Time is more of an issue right now than money--I'm trying to get everything ordered that seems likely to help (everything has to come by mail, and it takes about a week for stuff to get here. If things go right--). I have in hand a Transgo A4LD Jr. shift kit, the two small electric shift solenoids (TCC and 3-4 shift), plus the filter and a wrong pan gasket that needs to be replaced. (wrong parts are normal, BTW--I expect to get at least 10% bad or wrong parts).

I've been through most of the relevant threads, with great interest. I have an ATSG manual for the A4LD and a Chiltons for the Aerostar. I'm a fairly competent shade-tree mechanic with no previous experience on trannies.

The vehicle in question has about 100k miles, presumably with no previous maintenance on the trans. It's incredibly dirty inside, but the crud seems to be basically wear products. The fluid was full, not burnt, but nearly black with dirt.

So, now to the first question.

What is the fix and the essential replacement parts for the Low-reverse servo? I don't see any issues with it, except for the dirt, which I have already removed.

I haven't pulled the separator plate yet, but my impression of the job is just to remove, clean and inspect each valve spool one at a time, replacing what I can, which is basically the parts I've listed above. I'm planning to order parts today, starting with a boost valve (the high ratio boost valve with O-rings, right?), another pan gasket, and a set of numbered drill bits for the shift kit. All I can seem to find for the L-R servo is a gasket and this-

A4LD 4R44E 5R55E Transmisse reverse servo D ring kit

from Transmission Parts USA. I can't seem to figure out what a D ring kit is, or if it's gonna help.

Any thoughts?

Thanks,

PK

 

[BrooklynBay]

Welcome to this forum! I've moved your post into its own thread in the Aerostar section. The TransTec D ring kit is an upgrade from the stock O rings on the low/reverse servo. There is also a double lip seal in one of those shift kits, but I would recommend the D ring kit since it makes a tighter fit. Automatic transmissions require a meticulously clean environment in order to shift correctly. The dirt might be fragments from the bands, clutch plates, seals, gaskets, thrust washers, and other internal parts, so expect to rebuild the transmission if the valve body rebuild doesn't fix all of the problems.

By the way, your profile says 95 but your first post says 91. Do you have two Aerostars?

 

[pdknz]

By the way, your profile says 95 but your first post says 91. Do you have two Aerostars?

Hi BB--

Thanks for the reply, and for the advice.

To answer your question, I have a 95 Explorer and a 91 Aerostar. The Aerostar has turned out to be my pilot project because it looks like I might not have to pull the transmission to get it back on the road. Hope it turns out that way. The 95 Explorer has been dead for a year or more, and it's going to be a long term project. I saw an interesting thread yesteday about swapping an automatic for a stick shift, and I might give it a try someday. The ideal vehicle here is probably a 4 cylinder, stick shift with EFI. Be interesting to see if I can get there with an Explorer.

I cleaned up the gasket material on the (Aerostar A4LD) valve body last night, rinsed it with liquid wrench, and started on the shift kit installation. I need to bide my time for a while until the rest of the parts get here, including gaskets and the D ring kit. Transmission Parts USA emailed yesteday with the news that they mailed my order the same day I placed it. How cool is that?

I really appreciate having this forum to go to for help, BTW. Our little town doesn't have any professional car-fixin' shops, so it's all pretty much DIY. I'm trying to get this job done and the car back on the road for several reasons, mostly to do with cold weather. It's -35 this morning, and the Aerostar has been pretty good about starting in cold weather, which is probably one of the main reasons the transmission has so much wear, and also why I want it on the road.

If anyone is curious about really cold weather operation of vehicles, I can start a thread about that. Cold weather here is in the range of about -30 to -60F.

 

[BrooklynBay]

With weather like that, you could probably drive without a radiator or coolant, and never over heat. What's the highest temperature that you get during the summer? The 95 Explorer has a thermostatic bypass in the valve body. With such cold weather, it probably doesn't open that ofter to circulate transmission fluid into the cooler. Your 91 Aerostar doesn't have that part, so it always circulates fluid through the cooler.

 

[pdknz]

With weather like that, you could probably drive without a radiator or coolant, and never over heat. What's the highest temperature that you get during the summer? The 95 Explorer has a thermostatic bypass in the valve body. With such cold weather, it probably doesn't open that ofter to circulate transmission fluid into the cooler. Your 91 Aerostar doesn't have that part, so it always circulates fluid through the cooler.

Hi again, BrooklynBay--

I'm reduced to waiting for parts again on that job. I ordered a batch of stuff on Monday and then realized that I need more check balls because the shift kit calls for one extra. So that puts the reassembly off until sometime next week.

Since you mention cooling, let me unload about that for a while.

The usual engine heating arrangement is a three-way or four-way electrical outlet, with a freezeplug heater (600 Watts), a battery pad heater (50 or 60 Watts) and an oil pan heater (70 Watts or so). It's always a temptation to add a heating pad on the transmission pan, but instead, I have started adding a trickle charger for the battery. Most modern cars will start down to about -20 or -30 if they are in good shape, but the maintenance cost gets really high if you do that for a year or two--the starter and ring gear are at risk, and the engine and transmission wear from a cold weather start equals many thousands of miles of driving. I was once advised to put an electric space heater inside the passenger compartment to prevent, say breaking the steering wheel or ignition switch from moving them when they are cold, but that makes the power requirement so high that you can't plug in two cars on the same circuit. Fords in particular tend to blow the high pressure power steering hose in cold weather, so it helps to not touch the steering until the engine warms up for a while. Needless to say, heated indoor storage helps a lot.

Transmission coolers. When I got that Aerostar, it needed an engine swap, and nobody was willing to do the work, even with the spare engine right there. The project came to me for free, and it has cost about $2000 so far to keep it running for a year. In addition to the engine swap, I've replaced the waterpump and timing set, sensors, gaskets and plugs all around, the belts and hoses, the radiator, heater core, tires, spark plugs and fluids. The transmission cooling lines bypassed the radiator because of an internal leak, so hence the new radiator. I thought about keeping the bypass, but decided that the radiator might actually heat the transmission, at least occasionally, so I put that all back to original.

Driving here is short trips. It's about 2 miles to the school and 6 miles to the post office, so that's the usual daily run, but it's also pretty much as far as you can go by car. The job I have in mind for the Aerostar is to haul my wife, daughter, and grandkids to school and work every day, so it needs to be pretty good at starting in cold weather and driving short distances on snowy roads. If I can get the tranny and the doors lined up, I think it will about be there.

I really like the AWD, by the way. I put new studded all weather tires on it last year, and for a van, it's very competent on the road even with those tiny little 195/75R14 tires. I think it will make a good mom car, provided I can get it running reliably.

Looking back, I see that you asked about our highest temps. That's around 80F for a few weeks in the summer. One of my goals for this winter is to finish up a heated garage for another vehicle or two. The school group took off with my Jeep this morning. It was stored overnight in my blacksmith shop, so it started fine, but the ignition key gets so stiff I'm concerned about leaving it out in cold weather. And it's the last car running as of today.

Back on subject. I wish that when I buy or order a repair kit it would include enough stuff to actually do the job. The shift kit that calls for an extra check ball for example. What a gratuitous insult. And ordering three sets of gaskets (valve body, pan, and LR servo) to do one simple job. Dammit.

Thanks again for the note. As you see, I like to yak about this kinda stuff.

 

[BrooklynBay]

You could use a larger tire size if you want. Another heat related question. What do people do if they have to park in the street without access to electricity for the block heater or blanket? I don't think that it will be able to start without the pre heating equipment.

 

[pdknz]

You could use a larger tire size if you want. Another heat related question. What do people do if they have to park in the street without access to electricity for the block heater or blanket? I don't think that it will be able to start without the pre heating equipment.

Yeah. I thought several times about bigger tires, but it's done now. Odds are the tires will last as long as the van. 5000 miles a year is a lot of driving here. Tires usually fail because they won't hold air rather than actually wearing out. No tire shop here--we buy our tires by mail, and my son has a tire machine, so we mount them oursleves.

Good question about parking without heat, but it doesn't come up much. It takes an engine a few hours to cool off so much that it won't start, so you can let it set for half a day. There are plug-ins (some of the north slope workers call them the bull rail) at most places of work, including the school and the powerplant, and at home, of course. In Fairbanks, you can find outlets that take fees like a parking meter, sometimes by card. The motels and the car rental outfits have heater outlets.

The only time the problem really presents is when we fly out. If it's cold, we will have someone drop us off and get a ride home when we return so as to avoid leaving a car at the airport. The town is so small it's perfectly possible to walk home from anywhere, and usually not hard to get a ride anyway. In really cold weather a lot of people just dress warm and walk to work.

 

[BrooklynBay]

It sounds like an electric vehicle would be a better option since it doesn't have to be driven that much, and you have access in many places to recharge it. A deep cycle battery would work under severe weather conditions.

 

[pdknz]

It sounds like an electric vehicle would be a better option since it doesn't have to be driven that much, and you have access in many places to recharge it. A deep cycle battery would work under severe weather conditions.

With you on that. I think it will come to pass, but as it happens, I don't have one right now ;^)

Even better would be renewable ekultricity to charge it with, and we are working on that. Wood chips, for a start. In-stream hydro from the river maybe someday (the ice and floating crap in the river is an issue). Solar electricity someday soon. I would like to see some improved batteries for an electric car, though. Lead acid batteries need to be fairly warm to put out correctly, so hence the battery heaters and trickle chargers.

-45 this morning, but the neighbors got a car running, so I'm off the hook for a while.

Thanks for the conversation, BB. Always glad to yak.