Has anyone had experience with Transtar torque converters? I've decided I'm not going to drop the money on a billet converter to put between a mostly stock engine and a transmission with at least 100k on it. I've trawled the internet and haven't really found anything negative about them, but if anyone has used them before I'd like to hear your thoughts.

 

Another question just came up while I was doing some reading. Is there a way to tell (preferably without opening up the transmission) whether I have a PWM or non-PWM 4R100? The truck is early '99 with a 4/98 build date, but I believe the transmission had been replaced before I got my hands on it.

 

Isn't on/off versus PWM a function of the PCM's strategy?

 

I'm not real sure. There's a replacement TCC valve from Sonnax that says it's only for PWM 4R100s and isn't needed on non-PWM 4R100s. I don't know if it was a design change somewhere in the production run of 4R100s, or what the deal is.

 

I think I recall Mark K saying that E99 4R100's were non-PWM. Hopefully he'll cruise in and get more specific.

I'm pretty sure people have had luck using a 5R110 convertor...maybe search that.

 

Yes there is, but I don't have all the details.

The solenoid is different between the PWM and the on-off. You can check the resistance across the solenoid without opening the trans and tell which one you have. All you need is the resistance values and a wiring diagram of the transmission connector. I have neither of those.

And of the different solenoid and of changes in the pump body circuits.

I have used several Transtar torque converters. For stock applications they have worked very well for me.

 

Thanks Mark. That's reassuring about the Transtar converters.

I finally found some more information on the PWM vs on/off. Apparently the PWM model will have F8 stamped somewhere on the pump. I just hope it's on the outside, lol.

 

There IS a way you can tell if your TCC is PWM or On/Off without taking apart your transmission.

Here is how I learned how to tell on my truck, about 13 years ago:




Only had film back then, so I included one of the prints in this digital pic of the pin out diagram I used to find the TCC circuit to tap an indicator light into.

As seen in the transmission Connector #1048 in the diagram on the left, you want to look at pin Socket #4, where I put the yellow post it arrow. The wire color is purple with a yellow stripe. This is Circuit #480. It goes to Pin #54 of the PCM, as seen on the diagram to the right, via Connector #1027.

When the PCM pulls Circuit 480 to ground, the TCC solenoid is activated and lock up happens. Whether or not it happens gradually (PWM) or suddenly (On/Off) can be "observed" by attaching the cathode of a low milliamp 12v LED light with a resistor to this purple wire w/ yellow stripe, and then attaching the anode to 12 volts.

Since the PCM (through Pin 54) provides the ground for Circuit 480 when the TCC is commanded to engage, then if you've already supplied 12v to the LED, the light will illuminate when ground is given. If the light flickers for a little while when it illuminates, then that is your indication that you have a PWM set up.

Here is how it looks on my A pillar:



This light has been useful to me, because at times I could not distinguish between a shift versus the lock up engagement by sound and feel alone. It can be useful to you to as a relatively non invasive way to determine what type of TCC engagement you have.

 

Don't worry about a non-PWM (on/off) torque converter clutch solenoid and related pump valving in a 7.3L or V-10 transmission. The ONLY factory non-PWM 4R100s were behind the V-8 model 4r100 transmissions.

Look at it this way, if the E99 4R100 transmissions were non-PWM, a 99.5-01 computer swap would cause a really weird feeling torque converter clutch apply. The programming for all E99 7.3L trucks incorporates a torque converter clutch apply rate map.

 

Good explanation. I didn't realize there were any differences between the 5.4 4R100 and the others. I'm not much of a transmission guy. I think I've had one of them opened up in my life, and it ended up going to a shop instead of me messing with it.

 

It's funny you mention that because I just rebuilt another 4R100 today. I love having clean, soft hands....if only for a day.

 

Don't get me wrong, I'd love to know more about them. I just don't, and it seems like a fairly steep learning curve. Also seems pretty easy to cause damage if I get something wrong

 

And on this and another 99-03 7.3L Diesel specific forum that prohibits gas engined discussions, moderator Mark Kovalsky, former Ford Automatic Transmission engineer in the year 1999, wrote:


What we have here is a conflict of information. Can you guys sort this out?

 

Hmmm.

I can program a stock 4R100 using an XLEx PCM to essentially act as an on/off setup...watch out for the mule kicking the seatback at 45 MPH under normal acceleration. I recently (as of about a week ago) did some live tuning on an E99 with an XLE4 and BTS using an aftermarket on/off setup (pump and solenoid). Don't try to make the stock PWM mapping work with one of those.

Mark has said many times that he wasn't involved with the 4R100. While his technical expertise concerning automatic transmission operation and theory is unsurpassed in the forum world, the tuning aspect (as well as those who have rebuilt a few) says otherwise.

 

I wanted to get back in here and express my views a little more just so everyone realizes that I know I am not perfect nor always right. I'm a pretty humble person "in real life" although I can come across pretty darn bull-headed and a bit pompous in no-see-um land. I assure you that it is simply due to the demeanor that I take when communicating; I'm a no BS kind of person and beating around the bush isn't exactly my style when it comes to making a point.

That being said, there will always be arguments regarding different viewpoints regardless of who says them or types them. For instance, there are those that will say Ford never made a Superduty with rear brake calipers that were on differing sides of the axle tube (fore and aft) after early 2000. My truck is living proof that some carryover axles must have been used pretty late into the 2000 model year season. There will always be those that are steadfast in their belief that "powdered metal" connecting rods are going to be in engines made only after 2001 and that all 2002 engines are going to be powdered metal. Again, not always the case. I've also come across a 2000 model year Supercab with the good seatbelts (seat-mounted instead of roof-mounted) factory-installed.

The point I'm trying to make is that it IS possible some 7.3L 4R100 transmissions made their way out of the Ford assembly plant with a non-PWM setup. I haven't been around long enough to see one though I guess, nor have I come across a non-PWM DPC-402 PCM calibration. I'm not talking about vans here (different PCM anyway and not the topic of this discussion)......they're a different animal altogether in most cases and since they're so, well, rare I doubt I'll ever have the opportunity to actually see one apart to find out.

I am certainly not trying to say that there is no way a F250/350 came from the factory with a non-PWM torque converter clutch but I'm pretty darn sure that someone could spend a lifetime looking for one.