Engine/Transmission (1998.5 - 2002) Need some Trans advice

[EFielding]

for a '99 auto trans short bed 4x4 with 3:54 rear and 35,950 miles



Problem is this: between 45-50 mph unloaded (no towing), bed empty, the trans will "hunt", shifting between 4th and overdrive. This has been going on for about 4-5 months. I've taken the truck back to the dealer each time this has occured. Firtst time the PCM was reflashed. This worked for about a month, then started again. Second time the electrical grounds were faulty. Repaired and same thing; good for about a month or more. Trans has started the same thing again, and is driving me nuts



I did a search of the board, but cannot locate anyone with the same problem. Anyone got any ideas?? I'm open to any and all suggestions. Fluid level is ok. EGT's are ok.



I just made a 450 mile r/t to Kalifornia last weekend; set the cruise on 80 and slid on down the road with zero problems. Got off the interstate and we're back to square one AGAIN!



Dealer obviously has no clue.



Thanks guys. I appreciate your input.

 

[fox]

Has anyone cleaned the tps ( throttle position sensor )?

I think it is a player in this problem. Take the cover off of it ( it is at the injection pump ) and spray it with a cleaner made for electrical circuits. DO NOT USE BRAKE CLEANER .

I bet it will cure your problem. If it doesn't , well it was cheap!!



fox

 

[EFielding]

Fox

I'll give that a try and see what happens. I'm not sure if that's been done. I know I haven't tried that. I'll let you know.



Thanks...

 

[Pit Bull]

Check the following

1. Front band adjustment.

2. Check for excessive foam on the dipstick after normal driving. Could be loose pump bolts, devective gasket, or the pump assembly needs to be replaced.

3. It could also be a throttle linkage problem - Have it adjusted.

4. Could be a clogged transmission fluid filter - If it is clogged, check it for metal etc. that could indicate the need for an overhaul.

Hope this helps.

 

[BBradley]

Trans Problem

My 2 cents is the TPS. I had the same problem and dealer replaced TPS after doing the TSB flashing. No more problemsOo. Good Luck.

 

[deezuldon]

For what it's worth, you're not alone! I have a '99 4x2, auto trans, 3. 53 rear. EXACTLY the same problem. Lock/unlock of the TC between 45-50 (1200-1500 rpm) in overdrive. Drives ya friggin' nuts! Only way around it was to "turn off" the overdrive, but that gets to be a pain in traffic. And then it would do it between around 30 and 35 (1200-1500 rpms once again), out of overdrive, in third.



So a few months ago, took it to one of the better dealers here in So. Calif (Fullerton Dodge - there's a tech there who's a TDR member and actually speaks "diesel"! What a concept!). Re-flashed the computer. No change in performance as others have complained- apparently there's more than one "selection" of reflash. Solved problem.



Until about two months ago. Repeat of the old problem. Called the tech at Fullerton Dodge: Do I have to keep getting reflashed?He suggested it might be a ground problem. Pulled off the cheesy ground wire on the PCM (back on the firewall - behind the turbo), cleaned and reinstalled. Pulled off connection at other end - sheet metal screw into firewall - cleaned it well, put back together - Voila! Problem solved.



Until two weeks ago. Tried cleaning up the ground wire connections again. No change. Added a separate ground wire (2 Ga. ) from PCM to negative post on battery on same side of compartment. From there, there's a factory ground wire from the neg post of the battery to the block, probably a 00 cable. Plenty of ground. No dice.



Called dealer tech. Said it might be RFI or EMI problem(interference, electronic "noise" as it were), disconnect alternator & drive. If there's noise coming from the alternator, disconnecting it will make it go away. No change. At this point truck goes to dealer next week. He's going to connect a scanner and see what he comes up with between 45-50... thinking maybe a faulty sensor. What ever the hell it is... drives ya nuts! Will let you know.



Has to be voltage based somehow. With all electronic engines anymore they see changes in voltage or ground in miniscule amounts and you can't "see" any of that without proper electronic diagnostic tools. You get to that point where you say: "F. . it! Just fix the damn thing... . "



(Really no complaints - truck's been bullet-proof for over 3 years otherwise. )



Deezuldon

 

[EFielding]

Deezul

Da*n!! Welcome to the club!



Finally, someone with the same problem. My truck went to the dealers yesterday (for the 4th time for this problem). After looking at and cleaning the TPS ( Thanks Fox and Pit Bull), problem was still there. On arrival at the dealers, service manager took a ride in the truck. Yep, he says, truck hunts between 45-50. Duh! This is the 4th time in to correct this problem. Got a call from the service writer (who's not abad guy and is trying his best) and he said: looked at the TPS, it's ok. Checked the input and output voltage, thats ok. Checked the PCM, thats ok. Checked the grounds (that got checked on the 3rd trip in) their ok. Finally, he says that the tech called STAR(??) at DC and they indicated possible intermittent short somewhere in the wiring. Yikes!! Where in the wiring, I ask? Don't know, says he. Then he says, next time it does this, bring it back. No problem says I. You'll keep getting it back 'till it's fixed! Dealer is close, I got the time, and the work is covered under warranty (in as much as the problem started at anout 20K miles).



So, with that said, I'm still at square one. If I get mine fixed afore you, I'll let you know what magic the dealer wrought!



I'm 'just about' ready to go to ATS or DTT and dump the stock trans but I "really" don't want to spend $3200 that I can put somewhere else. AND, I don't think it's the trans. Probably some esoteric electronic doohicky that went south. Da*n, whatever happened to Powerglides?



Good Luck.

 

[Briar Hopper]

Ed, I'd get the problem solved BEFORE replacing or upgrading the transmission. With a possible electronic/electrical malfunction elsewhere than the transmission, you may be WORSE off than when you started, if you get it replaced. You have a luxury most of us don't..... time.....

If you get tired of the dealers, find a GOOD transmission shop(or two, or three!), a simple diagnosis won't cost much, if at all. Such shops often get better technicians with more experience than the dealerships do...

 

[EFielding]

Briar

Yeah, I'm aware of the potential problems without fixing the existing ones. BUT, if this problem turns out to BE the trans.....



As to existing shops, I'm in the hinterlands of northern Arizona. Not too much to choose from up here. The closest thing I've got is some guy that's franchised to install Banks equipment. Gotta go all the way south to Phoenix for someone decent. AND, I'm not sure who in Phoenix I'd let screw with my truck.



But, your point is well taken.



Ed

 

[BFC]

I'm not sure who in Phoenix I'd let screw with my truck.

Easy, call Fred Swanson, he's on the outskirt of Phoenix. Super nice and freindly guy, TDR member too. He'll help ya out. Ohhhhhhh, did I mention he's a transmission guy and dealer for a lot of toys



(623) 910-9575 or http://www.desertdieselparts.com/



Glenn

 

[emjay]

I read somewhere that separating the TPS wires from the rest of the harness by pulling them out of the conduit may help with electrical noise on the TPS signal wires. If you're more adventurous (or desparate) you may also try placing a 0. 1 uF (microfarad) capacitor between the TPS signal and the TPS ground as close to the PCM as possible with a good, solid connection.



From what you described, it sounds like the torque converter is locking/unlocking at light throttle. Unfortunately, the PCM is designed to unlock the torque converter when you let off the accelerator pedal. The problem is what the PCM "thinks" is closed throttle. My '00 3500 will constantly lock and unlock the TC on flat ground, unloaded with the cruise control on at 35 MPH. The problem there is:



1. The momentum of TC causes a slight accceleration when it locks.



2. The cruise control sees this acceleration, and backs off the throttle, which unlocks the TC.



3. When the speed drops, the cruise control applies throttle, a few seconds later the TC clutch locks again, and we're back to #1.



Adjusting the TPS voltage at idle may help, but, in my opinion, the problem is the "dumb" unlocking of the torque converter when the throttle is closed.



When you're driving at higher speeds, there is more wind resistance, etc. , which requires more pedal, and the problem disappears.



The intermittent nature that some have experienced is likely due to the fact that the system operates on the "hairy edge" and making minor changes like ground wires, etc. changes the behavior for a while. The TPS signal itself is notoriously noisy, even under the best circumstances.



Also, it is possible that by re-flashing the PCM, it resets to the default calibration, which eventually gets "optimized" by the PCM doing its own calibration over time. You can test that theory by unplugging the PCM (all three connectors to be safe), and plug it back in after a minute or two.



Anyway, I'm rambling. Hopefully you will gain some insight from all of this to fix the problem.



Good luck!

 

[Wolfgang]

I had the same problem with my 01. I thought is was normal so I never worried about it. Figured it was at the shift point and the computer was the problem. Since then I have had a DTT TC, VB, clutch's and a Smart Controller added. No more problem. Maybe I did have a problem before but it is gone now

 

[deezuldon]

Trannies - wonderful mystical trannies....

Some good input from all, eh Ed? Hopefully it won't take me 4 trips (or more) to the dealer!



Has to be an "electrical" problem of some sort. The transmission's controlled by the PCM, so it has to be something to do with the PCM or input to the PCM. Input to the PCM by a faulty sensor? Maybe. Shorted wire, could always be - that's a bear to sort out. Bad ground? Shouldn't be - already "upgraded" that connection. Stray interference? Who knows. I'm tired of messin' with it. I'll pay the dealer to sort it out. He can ride around with the scanner plugged in, and with any luck, the fault will show up. (Fingers tightly crossed. )



I inquired about even replacing the PCM outright - is there an "upgraded" version? Was told that they're the same, and would still have to be flashed right out of the box before installing.



Go figure!





(Anybody know if there's a way around this? Different valve body with shift points at different rpms? If a transient problem like this continues on, it essentially ruins confidence in the truck. And I'm happy otherwise. But if I have the experience Ed's having, that could certainly change!)



I'll know more soon. Truck goes in 8/14 won't be able to pick truck until Mon 8/19. Hopefully I'll have some more insight - and some positive things to say!



Electronics are wonderful... when they work as designed!

 

[EFielding]

Deezul,

Truck went in for service on Thursday last. So far, so good. Took it out to the nursery about 15 miles north and it ran without a problem



BUT, time will tell. Let's see what happens in about a month.



I think you're right. It's probably an input problem. Emjay is probably on the right track. But get the DEALER, to understand his rationale. For us guys that DRIVE these trucks on a daily basis, it makes perfect sense. Anyone that's masses with compouers, (PC's) KNOW that they have a mind of their own.



Anyway, let me know what the dealer finds with the scanner. If the determined fix works for you, I'll pass the same info along to the dealer (and vis versa). I'm also NOT opposed to a new valve body etc. if that will solve the problem.



Like you, I REALLY LIKE my truck and don't want to do something drastic (like unloading it), but... This problem is not unsolvable.



Let me know what you find out.



Oh, just an aside; opened the hood after getting the truck back. BOTH the screws and the plastic retaining nuts for the throttle cable box (APPS?)cover were missing. Duh?



See ya.....

 

[geneg]

hunting trans

I have the same problem. It's going into the shop for the third time. My prayers for a solution.

 

[Sageair]

Re: Briar

Originally posted by Ed Fielding

Yeah, I'm aware of the potential problems without fixing the existing ones. BUT, if this problem turns out to BE the trans.....



As to existing shops, I'm in the hinterlands of northern Arizona. Not too much to choose from up here. The closest thing I've got is some guy that's franchised to install Banks equipment. Gotta go all the way south to Phoenix for someone decent. AND, I'm not sure who in Phoenix I'd let screw with my truck.



But, your point is well taken.



Ed

Ed when I moved my son to Phoenix for school from northern Nevada I had been having lots of trouble with steering wander. I had a little spare time and decided to give Earnhardt Dodge a try. They replaced the steering box,no charge,and changed the oil for free because the truck wasn't ready until 4:30 when they had promised it would be done by 4:00. I was allowed ,even encouraged to speak with the tech who fixed my truck. I was amazed that a huge dealer like Earnhardt could give such personal service especially to someone just passing thru. Give em a try.

 

[EFielding]

Trans Update

Well, today is Sunday. My last transmission "fix" lasted exactly one week:{ Took it in on the 8th and the trans started to "hunt" again on the 15th



Deezul, you out there?? Get your ride back yet?? ANY fix for your problem?? Inquiring minds want to know!!



I was going to go into a lengthy diatribe, but what's the point?



STILL like the truck. HATE the electronics :{

 

[EFielding]

Sageair...

Thanks for the input. Maybe I'll give them a try.

 

[inarush76]

reflash

Have seen a number of 99 model trucks with this problem. If the PCM is cycling the TCC off and on, a reflash #18-02-99 may fix it. It is a software update, done at the dealer. Curious that the software needs "fixing" after working fine for several years on most trucks and that only the dealer can fix it with only a software change and no other parts! Makes one wonder. HTH



James

 

[deezuldon]

transmission fun, continued....

Ed (and others):



Just got off the phone w/ Dealer. Part of the process of taking the truck in was to have lift pump replaced (under warranty). Which they did last Friday - but the replacement pump was N/G! Apparently the lift pump mfr is reorganizing under bankruptcy laws - makes you wonder why they went BK... .



Anyway, dealer tech was able to reproduce the problem, i. e, observed the hunting problem himself on a test drive. That in itself is a good thing. The scanner was hooked up at the time, and no sensor faults showed. Apparently the lift pump has been known to have "noise" problems and may be a source of the TC lock/unlock problem. But it has to be running to check that out, and since it ain't running without a lift pump... the truck sits! Isn't that nice!



With a another new lift pump tomorrow, (fingers crossed) it should be running again... then we'll know more. I asked the question: What if the new lift pump doesn't solve the problem? "Then we have to go to the engineers at the factory. " Oh boy!



So the story goes on. There is some solace in the fact that there are a few of us, at least, having similar problems. Let's continue to communicate for the benefit of all of us!



Will post my experiences tomorrow, probably will be late in the day.



(By the way "76". Have done the reflash. That worked for a few months. If you look back a ways on this thread you'll see the sequence of events of my problem. And I think Ed suggested that he's done the reflash more than once... . But keep those cards & letters coming. Somebody, somewhere out there's gone through this and already have experienced a solution! What a concept!)



'Til later, fingers tightly crossed... .



Don (Deezuldon)