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Speed Sensors and ATF+4 and the like

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 #395443  by 135sohc
Today and yesterday both the Concorde decided to mess up. Nice enough to happen at the dry-dock aka the driveway and not while out and about. The problem being no speedometer and the limp in mode activated. Turn off and restart it would 'fix' itself and act normal.

Anyone who has messed with Chrysler's FWD 4 speed automatic might know about the running change for the 1998/1999 model year with the neutral safety switch/range position sensor. Where the early 1998 and older units used the 'round pin' style connection which over time would spring open and you would get intermittent connectivity even though externally it was all looking good.

The input and output speed sensor for the 42LE (and the conventional 41TE) use the same family of crappy round pin connectors. Unfortunately Chrysler never decided to upgrade the speed sensor connections to something like the Apex 2.8 series. For several years I have noticed the speedometer on this car has been sluggish, going from a full complete stop the needle would not move and then after its moving would instantly jump to 10-15 mph. The occasional clunky shift and at low speeds it would seem
lost and not sure what gear ratio it should be using.

5 years ago I was having an intermittent spark cut out on my 1994 shadow 2.2 and again the coil pack on that car uses another variant of the same crappy round terminal pins. When I found the terminals were sprung and had no positive contact on the mating portion of the coil pack. Chrysler figured out those terminals were bad news and updated that coil pack in the later 90's to a improved design and i did the same for the shadow and it has never been a problem since.

I pulled the transmission sub-harness today and de-pinned the two speed sensor connections. When bench testing with another speed sensor my suspicions were confirmed. All four harness terminals were very loose when inserted onto the speed sensor. I already had a spare set of the connectors on hand and cut off the old ones and spliced the new ones on. ... ce=0-0-1-1

I would prefer the shrouded styles ones like these which are the OEM type
input ... 98&jsn=802
output ... 98&jsn=805

But those prices are absurd. It is still the same crappy connector series that will fail in time anyways.
I can only imagine how many of these cars have been junked for a 'bad transmission' when more than likely one or both of those connections was just intermittent enough that it would never throw a fault code but still shift like complete garbage at the most random of times.
 #395445  by rustybronco
"I would prefer the shrouded styles ones like these which are the OEM type
input ... 98&jsn=802
output ... 98&jsn=805"

Go to your nearest Ford dealer. In the parts department, possibly the service department, they have those individual pins with about 5 inches of wire attached. If they act stupid like they don't know what you are referring to move on. They don't want to deal with selling you a few. Yes it's possible they don't make the kit anymore. I wish I could remember who they reordered the individual terminals from to restock. Been out of the game since 2019.

Note these are only the terminals, not the complete hardshell with wires.

Hardshell catalog. ... k-2016.pdf
 #395455  by 135sohc
That motorcraft catalog is nice.

On another forum I post on we have a thread just for electrical connectors. ... Connectors

The pre-made connector ends are a good option sometimes but they get expensive and bulky if all you need are some new terminals. The transmission speed sensor connections are made by Molex, atleast the OEM style with the 'shrouded' connection.

Today I took the car for a drive and the speedometer function was instant, watching the output RPM on my scan tool there was a signal as soon as the car was rolling. On the highway before if you really punched it, it would sometimes buck and kick, rolling up to a red light and then tipping the throttle back in to accelerate it would clunk as it was still in 4th when it should have downshifted to 1st or 2nd already. Low speed driving with a lot of stop and go or acceleration and then coming to almost a full stop and then accelerating again. Would really get it acting up.

Its like driving a completely different car now. I will call this one a confirmed kill fix.