Newly installed Suncoast -- couple of questions

sbohner · **Posted:** Wed Mar 12, 2008 4:34 pm

I just picked the CRD up after having the new Suncoast Torque Converter installed

. I noticed that it felt a considerably different. Most noticeable were the behaviors when slowing down to stop and just starting up slowly -- it tends to have some slight shutter at about 15 MPH. I tried a number of tests to see if it was operating properly including:

1. Stop and go -- slow and fast
2. Normal driving from 0 to 75 MPH
3. Moving quickly through the gears as I accelerate upto 75 MPH
4. Shift to neutral and listen for unfamiliar noises - sounded fine
5. Shift to reverse -- not while moving :-)

6. Tried 4WD in part-time, full-time, and Lo - in low it stalls the engine occasionally when break applied. I also tried reverse in all of these too and it seemed fine.

Are there other tests that I should try to ensure that it is operating properly? Are there things that I should look for after TC replacement like this?

In general, the TC feels more grabby and I wanted to know is this normal. It causes the engine to sound like it's under load a lot more. Anyway, if you have some experience with this, please let me know.

Again, thank you for any help you can offer.

Uffe · **Posted:** Wed Mar 12, 2008 4:58 pm

Thank you for posting about your Suncoast TC swap findings! Somewhere down the line I might have to do the same...

Stalling in 4LO?

That seems odd to me, perhaps a minor tune of the ECM would allow for a higher fuel input when 4LO mode is enabled to prevent it from stalling.

Not sure what you can do about it, but I'm sure there will be some of the more knowledgable guys here who can lend a helping hand on this

Joe Romas · **Posted:** Wed Mar 12, 2008 5:10 pm

I don't have a suncoast but two things come to mind. First check the fluid after it's totally warmed up. Second our transmissions are adaptive and it may need to relearn.

honey_don't · **Posted:** Wed Mar 12, 2008 5:19 pm

Joe Romas wrote:

I don't have a suncoast but two things come to mind. First check the fluid after it's totally warmed up. Second our transmissions are adaptive and it may need to relearn.

Try unhooking the battery for an hour or so (or overnite) to clear the memory. Can't hurt! I've read that it needs to be unhooked long enough for the capacitors to draw down.

stp2136 · **Joined:** Sat Sep 29, 2007 8:30 am **Posts:** 35

I also just put in a Suncoast. Mine was a little "grabby" at first but I think it was just low on fluid. I also drained the xmission and replaced the filters at the same time. At first it showed full with 8 qts of ATF +4 but I kept checking the level and ended up adding 4 more qts over the next several days for a total of 12 qts. It has stabilized now. Don't know if it was trapped air or what but it runs fine. I haven't added a lift pump yet (waiting on a new harness) so I am constantly bleeding air out of the fuel head. I think air in the fuel is also causing some "hesitation" which confuses the issue.

sbohner · **Posted:** Wed Mar 12, 2008 9:19 pm

Thanks! All of these things are helpful. I will try the battery disconnect and the tracking of the transmission fluid. I have had to bleed air out of my fuel filter once before - perhaps it wouldn't hurt to check that too.

Again, thanks! I look forward to hearing more as others chime in.

coldkj · **Posted:** Thu Mar 13, 2008 1:35 am

Had my Suncoast TC installed last week. Same shuddering at 15 to 20 mph, not all the time but more pronounced under heavy acceleration. Mileage might be 0.5 mpg better. Planning to leave battery off for about three days after I get the InMotion ECU flash next week, then will report results.

sbohner · **Posted:** Thu Mar 13, 2008 2:38 pm

Just an update. Was unable to make an appointment on this with the service folks for today, but will be taking the CRD in tomorrow morning. I haven't yet disconnected the battery, but will check if the service fellow did.

In driving it more since yesterday, the CRD with the new TC seems to do okay in highway driving, but poorly in slow city driving. Driving in stop&go traffic, it routinely stalls as I put on the break - particularly when their is a short acceleration just prior to the stop. There is a distinct shutter as I slow down after hard acceleration. There are some unusual noises when going slow (e.g., labored engine, slight whine from transmission), but no crunching/grinding or mechanical disconnects or unauthorized explosions :shock:

.

Hopefully, these things get ironed out over the next few days

. I'm looking forward to a better drive than the original TC that was starting to show signs of wear.

litton · **Posted:** Thu Mar 13, 2008 10:27 pm

Did you call Sun Coast and ask them what's going on??

sbohner · **Posted:** Fri Mar 14, 2008 11:52 am

Yes, I talked briefly with Ron and he suggested to take it back to the service folks and I did that today. He also suggested if they are challenged by it, they should call him. Needless to say, I'm eager to hear back from the service folks.

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

If the seal is torn in the trans could it act like this (stalling)? It seems that if the line pressure is whacked the converter will not work properly. Just a possibility. Mine has never stalled on me, but it will grab. I attribute it to the lower stall and higher torque mulitiplication factor.

MrMopar64 · **Posted:** Fri Mar 14, 2008 3:26 pm

It sounds to me that the solenoid for the lock-up clutch is stuck partially open allowing the Torque Converter to be in partial lock-up (this is a state). This engine will make an incredible amount of torque at idle and the only time I have seen this happen before is in a condition such as this (or the torque converter stator & turbine breaking, but that shouldn't be an issue with the Suncoast). Ask the dealer to use the scan tool to check all the solenoids and valves in the trans to ensure one of them doesn't have some junk in it or is otherwise sticking.

gmctd · **Posted:** Fri Mar 14, 2008 3:29 pm

Would depend on how it stalls - the aggressive hookup is more than ECM knows to compensate for, as it results in increased loading even at idle - this may be seen when observing transmission fluid temperatures, which may have run at 140deg at idle, now running 160-180deg at idle, transmission in any of the drive ranges

sbohner · **Posted:** Sat Mar 15, 2008 10:54 am

Well, I just picked up the CRD from the service folks. It no longer stalls at a stop. The fellow who worked on it isn't around and the paperwork is nowhere to be found. So, I can't report what was done. It was suggested that I come in on Monday to get the info on what was done.

The last word I had from yesterday was that they were going to change out the ATF+4 and reset the sensors (as explained to my wife on the phone).

Unfortunately, whien I picked it up this morning, the CRD is back to its mushy state like when I took it in with the original TC. The 4th and 5th gears to not seem to lock in as when it was new. I was was encouraged by the fact that there is not longer a distinct shutter. However, now it feels sloppy and there is a substantial delay after you push the accelerator and before the engine engages. Perhaps this will change as the adaption kicks in.

Does anyone have any thoughts on these latest symptoms? I'm being patient with the service guys as I do not think that they have had a lot of experience with CRDs. Perhaps some of you have some more ideas that might help (at least calm my frustrations

). Thanks for your help!

sbohner · **Posted:** Sat Mar 15, 2008 11:05 pm

After a day of driving, the adaption/learning mechanism seems to be kicking in. The mushiness appears to be giving way to a more assertive shift on the TC/Xmission. I must admit, my CRD felt pretty good with the more direct shift when it was malfunctioning -- too bad it also stalled when stopping.

This begs the question: Is there something in the sensors that if augmented, would cause the ECM/TCM to not torque limit during shift without the awkward consequence of the stalling at stop lights? Obviously, the ECM/TCM appear to be secured in such a way as to leave us no access to their reprogramming. However, like the SEGR, the sensors may have another avenue as demonstrated by my recent experience with the Suncoast install.

Anyway, just an update on the progress of my Suncoast install along with some food for thought. Again, the Suncoast is settling in and starting to feel better to drive. I hope that this is helpful.

Newly installed Suncoast -- couple of questions

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