I have an early 99 (12/6/98) F350 cc drw with the XLE4 PCM. About 8 yrs ago I upgraded the 4r100 transmission to ATS and torque converter to ATS triplelok. At that time the rest of the truck was completely stock. From that day on, I have always had a really harsh TC lockup. If I accelerate normally it’s not too bad but if I throttle hard up to 35mph (tach reads 2500rpm) and the let off the gas pedal the TC lockup is super hard. Or if I am towing up grade and the TC locks up it feels like it’s going to break something.
Currently I do have a hydra tuner so if this can be fixed via turning that would be great.

My question is where do the pulses come from initially
1. The PCM sends electronic pulses (PWM) to lockup the TC, which cycle the TC solenoid on and off very rapidly, that pulses the fluid to the TC lockup piston clutch so that the TC clutch engages more smoothly
Or
2. The PCM just send a single TC lockup signal, then the TC solenoid cycles on and off very rapidly, that pulses the fluid to the TC lockup piston clutch so that the TC clutch engages more smoothly
In other words what component does the rapid TC lockup cycling, the PCM or the transmission components?

I’m putting in a remanufacture motor this weekend and will have access to the transmission. I would like to see if I can fix this harsh TC lockup issue at the same time.

Any help with this is greatly appreciated.

 

The best way to control the harshness of the TC Cutch application is to change out the Pump and Solenoid Pack to a PWM model. The duty cycle of the TCC Solenoid can then be adjusted to slow down the application rate and timing of the TC Clutch through tuning or changing the PCM to one with later model shifting strategies; such as the PMT1. The Non-PWM is simply an "on-off" signal without control over the application rate, other than the bleed orifices and valves in the pump. The Ford part numbers for the PWM Pump and Solenoid Pack for your application are F81Z-7A103-CA and F81Z-7G391-AB.

 

Well I think I may already have the PWM solenoid packs and matching pump in the newer ATS transmission. I think the problem is I have an old XLE4 PCM that is only on/off. I think this mismatch is what is causing the harsh lockup. The question is would it be cheaper to replace the PCM with a newer model like a PMT1 or 2 and get new tunes or get old style on/off solenoid pack and TCC exhaust orifice on the pump?

 

If you could verify that you have the PWM parts, I would upgrade the PCM and tunes. I think you would be happier in the long run. Going back to the Non-PWM parts would be counter productive. You would still have no control of the TCC rate. I had the PWM parts in my transmission and put in the TransGo "on-off" conversion valve in the pump during rebuild. I could never tame the TCC application to my liking. Upshifts were okay, but downshifts from OD to 3rd were very harsh. I had to time the downshift and left off the throttle reduce the shock load.

 

That would work but $450 for a new PCM and programming another $150. Ouch. Do you know of a place to get a PMT1 or PMT2 for cheap?
Thanks

 

I would slow way down and let the stock tune take control, to learn what it does before I go shopping for parts. I have an HD4R100 and the only time I had harsh shift was with a chip. Tune programmers harden the shift by default, which makes the stock transmission feel like it's had a shift kit thrown in. Now... add the equivalent of a real shift kit and keep the hardened command - and you have crunchy shifts.

 

The issue the OP faces is determining the type of TCC application he has within the transmission and its compatibility with the shift strategies of his PCM/Tunes. He needs to figure out what he has in order to devise a plan of attack to remedy the situation. My recommendations are purely hypothetical at this point without knowing the facts. Typical internet diagnosis.

 

The DPC-4xx PCMs (402 in this case) are ALL setup as pulse width modulated control.

I'm with Tugly on this one (suspecting tunes with a combination of aftermarket parts). Let us know what you find.

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From the OP's first post, it sounds like the problem occurred with stock programming at the time of install. This points to a compatibility problem with the aftermarket trans and original shift strategies. The Hydra was installed later and had nothing to do with the original problem. It doesn't seem like it helped the matter any. We don't know what tuning changes were made within the tuner and if they are even correct for his application. Too many unknowns. Need more facts.

 

Yeah... I saw the word "Hydra" to go with harsh shifts - and my brain skipped a step. Sorry.

Back to the original question - tuning can tame the touchy torque converter.

 

Based on the information that Cody provided, I would agree and say "yes". The mfg date code made me suspect as to the TCC type; as it was close to the cut off for early to late builds. Still not sure which trans components he has since it was changed. The OEM should have been PWM, based on the PCM.

 

I was under the impression that the early 99 (mine is build date 6/98) had a XLE4 PCM with on/off signal, to match an on/off pump and solenoids, in the trans. Are you saying the XLE4 can be changed with tunes to soften the TC lockup? That would be awesome.

As far as more info I agree. I will be starting to pull the engine today hopefully and should know before the end of the weekend what pump and solenoids I have. Then I (with your help) can plan a strategy.

Let me know about the tunes for XLE4 to soften TC lockup
Thanks.

 

Not with an on/off PCM. The hardware in that PCM can only turn the TCC on or off, it cannot pulse width modulate the signal. No amount of tuning can change that, it's a hardware difference inside the PCM.

 

You stated, in your first post, that your truck had a build date of 12/06/98. Is it Dec '98 or June '98? I was basing my previous statement about early and late builds on that date. Are you sure of the PCM code and your build date? It is confusing as to what you really have. Guess we'll find out.

 

following this to find out where it goes!