RPM surge ?
 

I haven't look into it too much to be honest. Anyways, the trans has begun acting "funny". Never did this before. At certain speeds, holding the throttle steady, the rpms will begin to surge. You can feel the truck pull, and then calm down. Pull, then calm down. Needle is jumping around on the tach, probably a good 300-400 RPM's or more.

Also, the converter wont stay locked. No matter what speed, its only locked while I give it gas. I left off, it unlocks. Its doing this more often then it used to. And at some points, it doesn't know whether to lock or unlock, so its starts jumping back and forth.

This started a couple days ago. It's just acting different, and I am unsure what it is. I am fairly certain, its something to do with OD, Since its only acting up in 4th gear. Any ideas ???

If I were to hook up the proper scan tools, will there be any codes stored for trans ? And yes, I have access to dealership style scan tools.

:help:

Well the rpm surge is from the torque converter which I am sure you know...so I am no help:notallthere: But its definitely strange that it will not stay locked/and keeps jumping back and forth. Not that I think it has anything to do with it, but have you adjusted the custom options on the TC unlock/lock?

Just wondering...I know you said in OD only, but have you turned it off and seen if it will do it in just 3rd gear?

Maybe someone that knows a lot more than me will punch in...Good Luck man

hey no worries ! i appreciate all the help I can get.

Yes, the "surge" if from the converter, its just acting strange. If we weren't so busy, I'd be working on it now. When I turn OD off, 3rd acts fine. Converter locks when its suppose to, and stays locked. OD off, and its fine.

And no, I haven't touched the custom options. These are custom tunes from Bill. It was running great for many miles. Went to vegas, LA all multiple times. No issues. So, I do not think this has anything to do with the tune, but its just my trans on its last legs or something. Really not sure right now.... :shrug:

Still acting funny, and I am no closer to figuring it out !! :cursin:


could it be from running lean ? Its acting all kinds of "odd". I plan to bring it to the shop friday to tinker some more. SHould be slow enough to have some time.

Another thing to add, right before this started happening, I did the "gotts mod" type deal on my intake, to open it up some. Also dropped in a K&N air filter.

I also was feeling some "shudder". If you get up to speed, about 60 mph or so, then let off the gas and let it slow to roughly 40 mph, then slightly get back on the gas to get back up to speed, there is this violent shudder. Entire truck shakes, and does so very HARD and rapid. It feel like washboard road at 70 MPH. Knock some kidneys around ! Let off the gas, or turn off OD and it stops immediately.

Any help is hugely appreciated !!! This one has me scratching my head some.

The shudder is not new and is generally related to the converter locking up too quickly after tip-in. That is easily remedied.

I suppose the unstable idle could be related to a lean condition, although it is quite uncommon to see lean conditions at idle. It may also come from too much timing at idle. Try adjusting the custom option for timing back about 2 degrees (-2 degrees) and see if that resolves the unstable idle. If so, we can fix that and the shudder at the same time.

Thanks.

Cool. Can't thank ya enough Bill. Like I said, friday i should have time to tinker with it some. I will post back what I find.

And it seems fine at idle, while standing still. Its while in 4th gear that things start to seem really "off". Cruising at 52 MPH I found the rpms "hunt" some. They will shoot way up, then calm down, and bounce around a little. The converter will start locking and unlocking at slightly higher speeds. Also, converter will NOT stay locked. No matter what speed (took her up to 80 on the way home the other day to be sure) , if I remove my foot from the gas, the converter automatically unlocks.

If I turn OD off, truck drives almost completely fine. The issues are not any where near as pronounced.

Mine has done this a few times as well. The difference is mine does it at low speeds, and in second gear. I notice mine when going through school zones. I have talked to Bill , but my problem is that I can not make it happen when I want, so it is hard for Bill to fix the problem. My RPMs jump about 200-400 and the TQ is not locked and it does not seem to be jumping in and out of gears.

Converter unlocking during decel (ie. foot off the pedal) or when quicly accelerating (pressing down quickly on the throttle) is normal. However if the converter keeps locking and unlocking while at a steady cruise, there is a problem.

Let me know if this is what's happening.

Interestingly, at least to me, Bill, is how the converter tends to stay locked with the cruise control on when going downhill. At least it did on our trip to and from California. It's almost as though it's trying to maintain the speed in a coast situation (up to a point of course) instead of just letting the vehicle speed up.

Also, reducing the shift points and torque converter lockup points both for upshifts and downshifts does seem to have helped get rid of the "eagerness" to unlock under mild load that I complained about before.

I know this post is a bit of a hijack, but thought it might add something to the knowledge base.

- Jack

Oddly, I've never really paid attention as to whether the converter unlocked on decel when in cruise. Since it uses an inferred throttle value, I'd assume it handled shifting in a relatively similar fashion. I do know that the throttle feed rates are much less aggressive than using your foot which may account for less frequent unlocks.

I'll have to throw something in the Expy and go for a ride this evening so I can take a closer look.

Thanks for pointing that out. Might be quite helpful!

On cruise, the converter stays locked ! :2thumbs:



Hmm.... Because no matter what speed, it unlocks immediately. Doesn't feel right, but maybe just me looking for something wrong.

Anyways, yes, the converter will lock and unlock under steady acceleration. The RPMS also bounce around. when it first goes into 4th. I will feel the surge. While under steady pedal, I will feel the RPMs go up, and the truck pull (talking only a second) then drop right back down and feel slugish, then shoot back up and pull, etc. Maybe I should hook up a video camera on my guages so you can see whats happening. Sure is hard driving, and trying to stare at 8+ guages ! :doh:


Jack&Janet: don't worry about hijack at all. The more the better ! Really. :cool_beans:

Subscribed.

Ty

OK, this thing is sporadic at best. Trying to be able to give you details is hard. 3rd gear, everything is fine. 3rd gear, converter locked, rpms bounce around slightly, nothing bad. If its at 1800 rpm in 3rd, when it shifts to 4th it shoots up to 2400-2500 rpm. Then calms down. While in fourth, it will bounce between 1400 rpms, and 2300 RPMs pretty consistantly. During my drive on sunday, it jumped up to over 3k, then back down around 1900. When it jumps up, you can feel the engine pull, and you go faster. So, its not "dry revving" but fully engaged and still revving up.

I dropped timing -2, also tried -1 neither seemed to help at all.

Shudder is still there.

Don't want to have to mention this, but have you tried it with the STOCK program?

Just trying to eliminate weather its the tune or the tq converter.

Lars

That's got to be awful! I hope you and Bill can get this figured out soon. It DOES sort of sound like a TC that can't get itself locked up, doesn't it?

You say there's little RPM bounce in third? Is this with the OD locked out? And, is the TC locking properly here? (Sorry, I just went back and saw that you said it seemed "almost fine" in this condition in a previous post). But, that bothers me too. "Almost fine" is not good enough in my book.

So, this really sounds like a transmission problem, doesn't it?

And now I see that Lars has jumped in with a "perfect" question. If it runs fine in stock, the problem's with the tune, not the transmission.

- Jack

First thing I thought too, but it doesn't seem to be the tunes at all. I have run my 87 econ tune, and my 91 tow tune, along with stock tunes, nothing changes.

Yes, the little bounce was with OD locked out. Its pretty much how I drive my truck right now, jump in a turn OD off. There is a little bounce, but I didn't write those numbers down, so I will have to double check. You don't feel it like you do in 4th, thats for sure. I will get more numbers tonight, or tomorrow.

I think its something with the trans, but really not sure. Next step, is to undo the gotts mod. Not sure if I mentioned it already, but right before this starting happening, I did the gotts mod and a drop in K&N filter. I doubt this is the cause, but will take seconds to "undo" and test out.

Thanks for the help guys, keep the ideas coming !

update:

Trans is TOAST !! Gone ! :censored1::cursin:

Today driving to work, it was acting up more then usualy. Slipping more then I have ever felt. While driving back from a parts run, it slipped into nuetral, RPMS SHOT through the roof, and after that, only able to run in 1st gear, with some god awful noise. Reverse kinda work, but again, go awful noise.

Only code I got before this happened were:

P2106 Thottle Actuator Control System

P0720 Output Shaft Speed Sensor Circuit.

Looks like I am in the market for a new trans. Any aftermarket, beefy suggestions ????

Thanks for all the help leading up to this guys.

Oh, and trans fluid is clean as a whistle ! :shrug:


- James

Not much help, were we, James? Boy, I'm sorry for this to happen to you.

Anytime I hear about transmission problems, I get all nervous. Back in the 50's and early 60's, if you killed a transmission, you were best off just getting a new vehicle. No repair seemed to make it right. I thought finally we were getting to an era of more reliable transmissions. Maybe not?

I still wish my truck had a manual shift!

- Jack

Wow man that sucks :sigh: Hope you can get your ride back on the road soon.

Wow! That bites!

Sounds like something mechanical broke inside?
Pump?
If the fluid was clean the clutch bands should still be good.
You could go new and get the mfg warranty but $$$$
Or a reman with slightly less warranty.

Or tear it down and get it rebuilt with beefy parts.

Of the 3 I have had the best luck with the brand new one. You could also find a performance tranny shop and see what they have to offer?

Lars

PS Pull the pan to see what's in the bottom

Thanks guys. And don't worry, truck should be back up and running by late next week at the latest.

Haven't pulled it out, or done anything to it yet. Plan to start looking into the trans today. I will letcha all know if I find anything. Might be staying late and burning some of that midnight oil. Hopefully I still have some laying around somewhere !

For a replacement, I am looking into a reman right now. Problem with brand new is, Ford has a long list of "suggested upgrades" for these trans, but they wont do the upgrade. So I would be replacing it with the same problematic trans. Jasper Trans are reman, come with a 3 year, 100k warranty. Kinda nice. We also have our shop's trans guy. He wants to trade me for a reman thats been beefed up with Ford's "suggested improvements" or whatever. Anyone else know of any place to source upgraded internals ? I don't mind dropping $$$, if I get a bullet proof trans in return (if there is such a thing !:rofl: )

Almost tempted to pull everything and go all new drivetrain. Looked into it, to stay legal I have to find an engine from an 04 or newer. Boy would that be nice ! Not likely, but......

OK, called the extended warranty insurance company. They want me to do a full tear down of the trans to source the issue. WASTE OF TIME !!!! :cursin:

I deal with Mercedes extended warranties weekly, all diffrent insurance companies, never once had to do a tear down. Its simply R&R now a days. Kinda sucks and is going to suck plenty of time out of my weekend. Books gives me 11.5 hours for tear down. Should have it done by 6 hours or so. I better !

Looks like I am going with a Monster Trans. The SS Mega monster trans version. Rated for 600HP. Figure it'll hold with my little motor. Any opinions on this Bill ? Or anyone ?

Seems to me with everything I have heard, seen, or read that Monster has their $hit together. Closest thing on the market to being bullet proof.

Lars

PS Let us know what goodies you find in the pan and how the filter looks.

Filter looks like crap. TONS of clutch material in it.

Pan had lots of shards of metal, tons of clutch, lots and lots o' junk. I'll go and snap some pics. Its gone. Will barely even move right now, had to push the big POS onto the rack ! Man, was I out of breath ! lol

Glad to hear. I am getting lots of positive feedback about Monster. Thanks Lars.


- James

I dont have any personal experience with the monster trans, but I have also
read real great things about them

She's a lot more torn up than I would have thought!

Post some pics of the goodies in the pan.

Lars
:nonod:

Well, in an effort to give me a hand, Chris (guy I work with) washed the pan out for me while I was under my Sami workin on that. So, no pics, sorry guys.

Also, after doing some thinking, thought it would be best to get the truck in the hands of guys who builds trans for a living. Horgans Transmissions. We have been doing business with them for almost 20 some years now. Good guys. Really know what they are doing. So, I have brought the truck to them. They will do the RDI for me. They have already been talking to me about upgrades they can do, and they want to build me a 4R70W from the ground up. Going to see what they come up with. I'll keep yall updated.

clutches are gone.

No ring and no drum damage.

the 3rd gear was worn purdy good.

Starting to look like it was something in the electronics. Maybe the tunes themself but I don't know about that. I will get it back together, and hook up a gauge to watch the line rise pressure under acceleration. My guess is, the pressure wasn't rising, and was starving my trans of proper lube. Right now I am still not 100% sure what caused failure, but its looking like an electronic issue..... :sigh: Hopefully will know more by tomorrow or so.