89 Aerostar 3.0; blown seal after shifting problems noted over period of about 150 miles, then slippage then blown front seal.
- the trans had seemed to 'hunt' while MAINTAINING CONSTANT engine SPEED, THIS FOR ABOUT A WEEK prior to FIRST FAILURE event.. could feel shifting sensation with NO change in engine rpm.
SO I...
Installed used trans, drained, filter replace, filled, checked fill again,
sensitive to the 'hunting' sensation.. some small indication of same but
nowhere near the extent of previous, otherwise it shifted fine -well and solidly. No thump,, no hesitation- EXCEPT a couple times where slight 'tip-in' resulted in shift-up, rather than down.

BUT front seal blown again in 65 miles.

What I might have done wrong:
- Did not replace front seal, showed no wear on pump collar. or evidence of long term leakage in bell hsg

- Did not mount TC and check for run-out prior to install

- Did not check for pilot bush integrity

- Re-used the VSS on the van, instead of the one that came with the salvage-yard trans.

What I did right:

- Took care to properly align detents to shift lever, verified kick-down cable
free to adjust and lever moves freely. And, as noted, used the MLPS that came with used Trans.
- Stopped as soon as possible when I noticed trailing blue smoke... trans did not slip or otherwise act up, so I may have saved it. Though I'm obviously going to have to get a new TC.

- - - - - - -
AND YES... I am kicking my own ****, well and often for short-cutting

So maybe it comes down to either a mechanical problem... or a bum VSS.
I have seen a hint on web research that inop VSS happens at same time as
blown front seal.. so they may be related. In one of those there was a
cryptic ref to high pump pressures..

BUT; this is an 89, not one of the later versions where the PCM controls
everything, right? Will a faulty VSS in this series result in PCM trying to
engage two clutches at once? And does that result in the symptom?

DOES THE VSS cause these symptoms and result??
(Cruise Control didnt work either, natch, but hadnt for at least 25,000
prior to any indications of fault)
And how much can I expect to spend for the TC?
{added}
Or am I dealing with a rare case of faulty PCM?
-- - - --
Also noted:
Some slight indications of 'surge' in idle/Park or stopped in gear. But vac
modulator clear and no leaks. As I said smooth no-hesitation shifting
noted.

So, does anyone here with expertise have advice? I cant afford a full
rebuilt at this time.

Thanks in advance for your help... I'm pretty good on other problems but other than fluid/filter maintenance know very little about AT's other than general operation.

 

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Just for clarification, what's the VSS (sheepishly asking since I'm in the aerospace business and supposed to know all the TLA - Three-Letter-Acronyms real well)

 

copper
I think it is variable speed sensor

 

Welcome!

VSS= Vehicle Speed Sensor

Which the A4LD does not have. It is you basic 70s type tranny that is not run by electronics.

Well I hate to to be the baerer of bad news, but probably your original tranny was fine.

Blowing the front seal is a semi-common problem with the A4LD. Once blown, the seal is worthless and needs replaced. (which is your issue with the second tranny.)

I would replace the seal, and check the status of your modulator (probably one of the issues of your first tranny, $20 part.)

Also fluid level is critical; too low, too high, and you will have shifting issues.

This tranny is worked via vaccuum and a couple soliniods.

 

Thanks for the responses guys...
I wasnt sure if the PCM looked at the VSS for shift control or not... of course it HAS what I know as a VSS. The sender on the end of the speedo cable where it goes into the tailshaft.

So, then, in this series, the PCM controls the solenoids purely on the inputs of the Throttle Position Sensor and the MLPS (Manual Lever Position Switch)?

I didnt include there was no drippage from either trans prior to seal blowing out, though the original had SERIOUS shift then slippage problems.. and the fluid level was correct.

The current trans fluid level was correct ( checked thrice) prior to seal fail.. and still shifted correctly even after fluid started hitting the exhaust.

Well, after I pull it and look, I'll bet there's scoring on the pump drive/seal surface.. which will mean I have pilot alignment problems.

 

Oh joy! My wife's '92 Aerostar has 108,000 miles. How can I prevent this seal from blowing?

 

Put in the largest tranny cooler you can fit in front of the radiator. Change the tranny fluid every 30k with new filter or if using synthetic fluid, every 60k. Use 10 oz bottle of LubeGuard red every change, recommended by many auto manuf's and used by many tranny shops for long life and smoother shifting, helps to keep tranny temps lower, seals soft and pliable like factory new, valve body and valves clean and shifting properly. Make sure the transmission heat shield is in place on the exhaust system side of the tranny, some kiddy shops leave the heat shield off, higher commission.

Don't worry about the tranny cooler overcooling your system, the A4LD and 4R44 4R55 series of auto trannys used in the Aero have an internal thermostat bypass valve that bypasses all external cooling until the tranny reaches operating temp, about 180d F.

200k miles here and my 4R55 shifts smoother and runs cooler than new, extra inline cooler, synthetic trans. fluid and LubeGuard for last 100k miles. Tow 3,500 lb trailer 5k plus every summer.

 

And bear in mind... my original trans MAY have had 206k on it when it went. And typical 'just drive it' maintenance before I bought it.

Normally I wouldnt even bother complaining, because I would have bought a good rebuild but money is REAL tight.
- - - - -- - - - - - -

On the Ford newsgroup, a credible poster says he had an aerostar that blew fluid intermittently, only if he took engine rpm's way up.

- blowing fluid being defined by coating the rear window glass, which is my symptom... except mine kept dribbling

- - - - -- - -
Which brings me to the quirkiness of my truck (that's what I use it for- 'maintenance truck'):

Everything that happens to it, happens to fail dramatically. Or is of weird fail nature
*Water pump - no drips, then bearing comes apart at 30 mi of a 60 mile freeway trip.

* Radiator - minor seep ('have to replace that!'), then seam opens up on freeway, another trailing cloud of steam

* Brake rotor 'warp' Which turns out NOT to be a warp at all but a casting flaw which leaves a "thick" spot A VERY noticable difference in material at that point....

 

Well, first I understand the tranny got a cooler in '92 (as the mechanic I directed to add a cooler said one was already there). A lot of upgrades apparently were done in '92 including less prone to rocker panel rust. Second, I have changed the fluid regularly and it currently is filled with Redline D4 ATF. But third, I do sometimes sit and idle for periods of time (5 to 30 minutes depending and may open the hood on the longer ones). After a long period of idling (yesterday did it after 15 minutes) when I take off it is really loud like as if the fluid has thinned out and the torque converter is wheeling much faster than normal. That usually goes away after 10 seconds or so.

But another fluid situation that I think gets too hot is the power steering and I put in Redline and seeps became leaks. When I get the leaks fixed the Redline ATF should be a good bet there.

Based on all the underhood heat issues, I am convinced that synthetic motor oil is a good way to go in an Aerostar. I am running NAPA Synthetic now, but will be going over to Maxlife Synthetic.

 

Redline does make a Hi Temp ATF Mercon rated that does have a higher viscosity at hi temps. Might be good in high temp power steering apps where there is a lot of in tow and parking lot turning with overheating of pwr steering fluid, less burning, fluid breakdown and leakage.
I have not used it and have no experience with it.
D4 appears to be a lower viscosity ATF aimed at low climate temp operation
My Aero 4R55 loves Mobil Syn1 ATF Mercon and LubeGuard. No overheating on long hill pulls or extended idling charging the batts while camping.

http://www.redlineoil.com/pdf/3.pdf