Hard Shift

Hey guys I hate to bring back a thread but my solenoid pack is on it's way. It should be here Monday. I plan on doing a write up with pictures for everyone so where should I post it? Also how much Merc V do I need? Any tips on refilling the fluid? I hear that it's quite the pain.
Post it here if you want. Remember... the title of this thread was "hard shift". If your problems are resolved,,, the that's one more "point" for a fluid, filter, and solenoid change.

I suggest buying a case of Motorcraft Mercron 5. Valvoline would be the next best bet, (still Mercron 5). Anything left over can be used for a power steering fluid flush.

As far as filling the trans... Many "big box" stores sell a hand pump,,, but I opted for an Airtex E8016S fuel pump. After talking to Airtex,,, I got an "unofficial" answer that this pump would do tranny fluid, (and others), beyond it's design,,, but could not be "recommended" for my intended purpose.

Also... you are going to need some tubing and a fill "adaptor"... for the internal part of the drain plug on the LS. For about $10... you can but the OTC fill adaptor part #6604. Other copies may be cheaper.

BUT... the MOST IMPORTANT thing... is to make sure you can get the "fill plug",,, out of the drain plug!!! For the $15 or so insurance ordering from Ford... you may want to order this ahead of time. The issue is... that the fill plug "hex" strips out due to age and corrosion,,, which leads to ordering the drain plug assembly.

Just telling you what I know. Hope it helps.
Thanks for the heads up. The part arrived today and I tracked down the full plug parts. I am going to do the swap Tuesday. I'll let you know how it goes
My now scraped '03 LS8 had this exact issue twice (slamming 2-3 and shuddering 3-4 upshift) . Both times it was the PCM damaged by COP misfires. The first time a local trans shop said it's not the trans take it to Ford. Ford said the computer is OK we need to pull the pan, so I took it to a third shop. The third shop rebuilt the trans then told me it needed a PCM. It didn't need the trans. The second failure was really slamming 3-4 and barking the tires. It was screwing around, and it broke a hard part inside the trans. I tried to sell a really nice LS8 with factory HID's for $600. No takers, so I parted out the car and got $1400 out of it.
Mine is definitely trans related. It only occurs once the tranny is warmed up. I'm doing the surgery tomorrow morning and we will go from there. I got the car for 1000 so if I have to toss in a computer it's worth it. I do notice when the car is about to slam shift I hear the high pitch mosquito sound that only young people and dogs hear.
That noise is most likely solenoid related. Spring chatter/fluid bypass due to one of the valves not closing shut or sticking because that individual solenoid, (in the pack), is weak.
Well guys everything was going great until the wire harness broke off with the solenoid pack. The connector is on order now dammit.
I have reason to suspect that this connector got very hot. Which suggests that the previous owner probably sold the car due to the hard shifting and they may have also ignored the problem for a while. I wonder if we ignore these solenoid packs when they go bad if that allows the plug to overheat.
... I wonder if we ignore these solenoid packs when they go bad if that allows the plug to overheat.

That's very doubtful. It's a hundred times more likely that some damage or fault of the connector caused high resistance in one or more of the connections, causing heat to be dissipated there. Of course, this is assuming that it really was getting too hot. What are your reasons for suspecting this?
Because when I disconnected the solenoid pack from the trans and I unscrewed the retainer Screw in the plug the inside of the plug came out inside the solenoid pack. It is as if the plug was only held onto the solenoid pack by the wire leads.
Unless parts of it were melted or charred, I doubt that it was caused by excessive heat. I wonder if it could have been damaged by previous work?
Bnewton. Somtimes the plug sticks in the solenoid connector,,, simply due to age/time. Mine stuck some,,, but with some TLP, (tender loving persuasion), and trash talking... I was able to get it out. Obviously you were probably the first person to pull the connector.

Shit happens. Sorry to hear that. Are you planning on replacing just the connector??? That is going to be a chore with swapping all the individual wires and getting them back into their proper places.

I almost hate to mention it now... but if you can trace the harness back to the nect connector,,, it might be cheaper and easier to get a used harness from the boneyard.

Hopefully not too little... to late.
Yeah I am replacing the connector. It should be here tomorrow or Friday. The connector just disintegrated. My solenoid pack dropped nice and easy and the inside of the connector came with it. It was already in two pieces before I started the job. Sadly, the wire for the connector joins a harness above the trans and would probably require trans removal to trace. So I bought a kit that should just splice in.
If you are going to "cut and splice" each wire... make sure you solder every wire,,, and cover each wire with heat shrink tubing, (make sure you put the tubing on first ;)).

Also... go to one of the "big box" home stores,,, and get a piece of heat shrink tubing large enough to cover the whole splice afterwards. This will make the splice weather tight. Might even need to buy/borrow a heat gun.

Hopefully the harness you bought is color coded the same. If not,,, it will be a bit more challenging.
... and get a piece of heat shrink tubing large enough to cover the whole splice afterwards. This will make the splice weather tight.. ...

Only if you fill it with [copper safe] silicone calk before shrinking it. Alternately, dielectric grease could work too and you don't have to worry about it being copper safe. (Some formulations of silicone calk will corrode copper.)

Otherwise, for sure, heat shrink over a multi wire bundle will not be water tight at the ends.
Most of the larger heat shring tubing, (for underground electrical splices), has a glue/sealant on the inside... that melts when the heat is applied. Yeah... it might not seal a multi bundle wire. I would think that the dielectric grease would not set enough to keep joint watertight. Silicone, (copper safe), would probably be the best bet.
Hey guys. Anyone have access to a wiring diagram for this connector? None of the colors match. This is all I have

Here you are.


  • 2004LS_solenoids_conn.pdf
    542.5 KB · Views: 268
Thanks. Is there a reason they decided to make multiple wires in the same bundle share the same color? I am going to trace back to the pcm tomorrow morning.
Okay guys. Official diagnosis. I received a defective part. So I am probably going to sell my LS just because I start a new job Monday and I need reliable transportation. This is so unfortunate because I don't have time to completely break this back down again.
How did you determine that the new solenoid assembly was defective as opposed to a PCM fault, a wiring (and rewiring) fault, or another mechanical problem with the transmission?
Anyone have access to a wiring diagram for this connector? None of the colors match.

Unfortunately I saw this coming. Don't give up yet Bnewton! In the end you could get the tool to remove the individual pins in the connector. Sometimes a very small screwdrive will work. You may have accidentally crossed a couple wires when doing the splicing.

Which part are you saying was defective??? The replacement connector or the solenoid???

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