Transmission Help Please

bluestang2.3

New Member
Jun 29, 2007
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Pretty sure I'm answering my own question, but figured I'd give it a shot anyway. I have a 91 2.3 with the a4ld tranny. The Truckstang is closing in on 320K miles with no rebuild on the motor or the trans. I keep the fluids clean and maintain all regularly. We do tow a boat, a small pop up camper and a trailer with hauling stuff on occasion thus it's aptly named The Truckstang :)

Recently and not all the time, I've notice a wandering while in Overdrive. I don't over-rev and it shifts into the 4th and 5th OD fine, but once there I have some issues. Normally if you give it a little gas it stays in top gear and a little more gas it goes down into 4th, a little more and steps out of overdrive all together--Normal.

On occasion and randomly, it's starting to downshift completely out of OD when given even a touchof gas until pedal is let up a bit back to cruising. Also while cruising at around 55-65 I do notice a fluctuation in maybe 100 rpm or so on the tach- like a flutter. It's not a tach issue since I was hauling something with the hatch open and I could hear the exhaust fluctuation as well corresponding with the tach flutter.

I know this OD is electronic control and have tested the TPS and also I know that the OD is controlled in part by the MAF too which is also fine. I don't have any codes stored or in queue except for the EGR which has been deleted for many many miles and years. It is due for its annual trans fluid and filter change, but I was wondering if anyone had any suggestions. On a final note I do have an external transcooler installed and a high performance engine cooling fan but rarely does my engine ever get hot enough to run the fan unless I'm idling in traffic for a long long time. I've also installed a manual switch/relay to the fan motor for testing purposes to occasionally run it and prevent an overheating issue if for some reason a sensor fails. Since my fan rarely turns on, this will also help prevent it from locking up/rusting. whatever... Thanks Jeff
 
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I wish I could help but I actually have a question. I thought the A4LD was a 4-speed trans? You've referred to a 5th gear.

It has 3 regular "gears," a 4th that engages at about 35 MPH and finally 5th at 40-45 MPH. The difference between 4th and 5th is only a few hundred RPM'S and nothing major.

Oh and to add something else; on cold start up and until it warms up to operating temp everything is normal. Only when warmed up does it "act up."
 
That's not a 5th gear you're feeling, it's the torque converter going into lockup.

It's normal for it to come out of lockup when you modulate the throttle at cruise.

What's the fluid like in the trans? Has it been changed in the last 60K? Does it have a funny (stinky) smell to it?
 
You're right it isn't actually a "gear" per se and is a final lockup, I just referred to them as "gears". I am An ASE Mechanic, but don't know much about auto transmissions. I've had this car since 1991 and have religiously changed the fluids in it. It is due for a flush/filter and the fluid is not dirty or burnt up. De to my heavy "towing" usages I generally flush/filter every 50-60 K. It was due at about 315K so I'm about 5K over but nowhere near over on a 75K schedule. Also I know it's normal for it to kick down out of lockup and or full overdrive, but this is not normal. Even the slightest throttle change will cause is to "downshift"-- Thanks for the input
 
Bought my 89 with no od. Swapped in a $100 trans and it still works.

Given the reputation of these trans and your miles, I would rebuild.

There are a number of changes over the life of the trans. My 89 has two solenoids, an od inhibit and a tc clutch apply. Iirc, the transmission shifts hydraulicly, but these solenoids prevent the shift into 4th and the tc clutch lockup until the computer sees the speed and other inputs as ok.

Your 91 may be the three solenoid version, and I forgot what it controls.

At your miles, yours sounds rebuildable too.
 
So, I had a few days off work and decided to do some more troubleshooting since I was convinced that this was not actually a mechanical problem, but an electronic problem since the OD is electronically controlled. After the flush and filter change, the same problem still was present and again, no probs on cold engine, but warmed up----boom. I do have a decent diagnostic computer, but my friend has a wayyyy better one so we hooked it up. OBD1 isn't exactly the best to diagnose with, but we found it was actually a MAF issue even though there weren't any codes pending or stored.

Upon further investigation I/we found that a freakin MOUSE had chewed through the bottom of the air filter and started a nest in it. LOL a freakin mouse. I replaced the filter, disassembled and cleaned the MAF and now no problems. I really wasn't looking forward to a tranny rebuild and now I'm not having to. Now pushing 321K miles I'm running just fine and still heading towards my goal of 500K before I do a engine/tranny swap. Sometimes the simplest of things are overlooked and dammit a freaking mouse... LOL. Thank you guys for your inputs :)
 
Put wire mesh over the air filter inlet. I have to do that to my vehicles.

I never had rodents in my '89 GT, but have in every other car I've owned. They get into the cowl from the drains behind the fenders and drop into the vents. A few have been shredded in dash fans over the years. Picking their bits out is pretty gross. View attachment 108303

Kind of hard to but a wire mesh over the filter intake since I have a CAI system. The little bugger chewed right through the wire mesh on the filter itself, but TY for the suggestion :)