usd2sing

hi gang, im on a road trip at the moment. from fort worth, tx to redlands & riverside california.
i have picked up code P1870 twice today, trans component slipping????
trans temps are up. normal is 180-199 (cooler installed), actually saw 230 in traffic coming out of arizona. ambient temp was 82.
rpm trans, yank street/strip 2800stall.
code and rpm issues came out of nowhere.
i have 3:42's, my rpms are freaking out.
cruz control set to match speed limit of 75. rpms varied
from 2400-2900.

PLEASE ADVISE AS SOON AS POSSIBLE.
AM I STUCK IN CALI?.

planning a fluid flush tomorrow morning.
and other suggestions?

BTW:
also picked up a broken windshield from a POS arizona grading contractor dropping BOULDERS onto the high
way, right in front of me.
pulled them over, they told me to get ____. call thier shop and talked with the owner he told me to prove it and hung up on me...UGH! so tomorrow afternoon is a new windshield install, and im out 250 for the deduct.
so if im screwed on the trans, that would mean approx 5k in damages..

CARRJET

sorry to hear that, you might try some trans medic sold at most auto parts store to get you home. If you have to use your insurance, they might help, depends on who you are with....good luck

ToplessTexan

You're correct that P1870 is a trans component slipping indicator. It can take a while for the PCM to decide it's seeing this condition before the code sets, so you may notice some odd behavior that's part of the diagnostics prior to the code setting and lighting up the MIL. One action taken when it sets is to disallow lockup. This could be part of your RPM and heat issues. It would be important whether the temp increases were before or after inhibiting lockup. After is not so surprising, but before is a problem.

As to potential causes... Check to see if you sucked something up in the radiator area blocking your cooling. Check the fluid level before you flush, maybe it's low? If it is, be on the lookout for signs of leaks. If you have engine mods (i.e. more power) I wouldn't be too surprised to see a tranny failure. I'll keep my fingers crossed for you.

Just as an FYI, you can clear the code while driving. This will let it command lockup again. It won't fix the problem of course, but will give you a bit of an opportunity to observe what's going on more closely.

Good luck.

ToplessTexan

One more thought... You say temp got high in traffic. Is that bumper to bumper 2 MPH kind of traffic (i.e. no airflow other than fans) or just crowded highway? Is you cooler positioned such that the fans draw air through it? Are they programmed to com on at lower than factory temps?

stooze

I have the samr mods as you and now only a few hundred miles later I have a 'Check Engine' lite. The speed shop tells me the trany clutches are slipping. I have 78k on my '98 so age has something to do with it. Good news is that it will only cost $2500 for a rebuild compared to the $5K you mentioned. A quicker fix is still $1700 that was a clutch pack change so for a few hundred more one can get a total rebuild. If you can't get it home then look around where you are for a price to fix. Good luck.

sweetcharity

How long ago did you do the TC/Gear change?? It took mine a 150 miles or so to set that code after I changed to a sy3500/3.42 gears from 2.73 gears. I would say that your temp and rpm issues are due to the convertor not locking up. Also you should notice HARD slamming shifts when taking off from say... a stop light. this is another thing the computer tells the tranny to do in an effort to save itself. It increases the shift pressure to max. I LS1 edited the parameters of the noticed slip vs rpm to a range wider than the highest number seen on a scan tool during a test run to set the code. A long gradule hill at speeds around 45-50 miles an hour are the ideal conditions for this code to set. SOOOO when did you do your mods?? And I might add that when this problem plagued me, Topless Texan was a great help!

usd2sing

trans and tc have 8000mi on them. tune was done with them installed. this just came out of no where. your description is dead on when the temps get to 220+. so the tc is shot or im loosing something in the tune/puter.

im 1300mi from my shop. my puter is locked
thanks for the suggestion and help. its appreciated.
peace

usd2sing

update....did the trans fluid flush. made no difference at all...

ToplessTexan

Okay, so it's been fine since install. Good, that rules out basic tuning funnies related to the gear swap. I guess you didn't find any airflow blockages or signs of fluid leakage? No sign of particulate in the fluid? The real question is what caused the fluid temps to rise. Assuming it's not something simple like leaks or blockages, my bet is that it's not the converter but rather in the tranny. Your setup is not the easiest in the world to keep alive. (BTW, is your line pressure vacuum modulated or driven by the PCM? Are you running a MAF or no?) I'd call your shop for input given the warranty situation. Maybe they can point you to a local shop they can do some remote diagnosis with.

usd2sing

thanks.
maf, yes.
modulated....??? RPM trans for the c5. assuming pcm.
on the way home now. last night it seemed back to norm. didnt unlock for 3hrs. cruz set at 75.
maybe she just needed to stay at the holiday express...
leaving now on the second leg of the trip back. hope it works...

ToplessTexan

Good luck and keep an eye out for rising temps.

I ask about the vacuum modulation vs PCM controlled line pressure mainly because a low pressure situation could cause the slippage and heat you're seeing. The MAF (which is in the middle of the PCM's pressure control) is troublesome in your app, but probably not at the steady state highway cruise mode I assume you were in when this happened.

I'll be curious as to what the shop's thoughts are.

usd2sing

thanks bro.
wasnt able to contact the shop. i was on a road trip with a few hours diff in time zones. and it being a weekend didnt help either...

UPDATE:
found out that if i was at cruz and tapped the brake to release cc (traffic conditions, etc) it would release ok, the tc would also release (normal), but then would not lock back up. no matter what i tried, let off gas, or slight throttle. before doing either it would lock back up.

i did find that if i came to a complete stop, shut the car off, restart the car, then hop back on the highway everything was ok. tc/trans would lock up and off id go, temps stayed normal, until i accelerated for passing or had to tap the brake again, then it was back to freewheel/loose condition and temps started to rise.

even went as far as using the cruz increase and decrease buttons to slow and accelerate back up to highway speed. this actually worked. tc/trans stayed locked up. went thru 3 tanks of fuel today and didnt have a prob as long as i didnt touch the brake or accelerate hard with the pedal...

curtbriggs

so tomorrow afternoon is a new windshield install, and im out 250 for the deduct.
so if im screwed on the trans, that would mean approx 5k in damages.. [/QUOTE]

Some states have a law that makes insurance companies pay 100% for windshield replacement. It's a safety thing, they don't want people driving around with a face full of cracks, heh, heh,heh.

Cheers, Curt

ToplessTexan

This is starting to smell more like programming. Any chance this is the first time you've used cruise control since the install? Within the TCC control sections of the cal, there are parts for both normal and cruise modes. Most folks duplicate these so cruise is the same. It's possible they could be different. Let's say the TCC apply in cruise mode could never be satisfied - then you'd probably never get it back if it releases (unless you cycle cruise on and off maybe?) Something like that might be possible, but then again maybe not. The P1870 diagnostic only runs under conditions when the TCC has been commanded to apply, so if you're getting this code it's an indication that lockup has in fact been commanded. I'm having trouble coming up with an idea of what would allow it to be commanded but not successfully engage in cruise where you wouldn't have the same issue in non-cruise mode. Does it behave the same way when cruise is not on? There are several transmission state PIDs that could be useful in helping to determine what's really going on. There's a hint somewhere in the fact that the cruise accel/decel functions are not resulting in the same effects as the accel pedal and the brake.

usd2sing

added info....(my memory is going south on me..DOH!)

trans and tc installed when i had 3.15's.
installed 3.42s this past november. puter was reset to 3.42 gearing.
this was the first time using cruise control since the rear swap.

is this any help???

EDIT: only put 1000mi on the new rear prior to this 4k mi road trip.

123sugey

I Had Same Exact Problem With A Tci Converter. That Was The Problem

usd2sing

talked with rodney today, great guy.

99.9% sure its a programming issue.
we'll see.

ToplessTexan

I'll be curious to hear what the fix is. You said it was behaving differently with cruise on (misbehaving) and cruise off (behaving well), correct? Or was it only behaving correctly with cruise on and accel/decel control through the cruise switch? It'd be nice if it's programming. Did Rodney have any concerns about potential damage caused by the overheating?

usd2sing

he didnt seem to troubled with the temps, considering i shut down and parked it once they got up there.
it happened in both scenario's, with and w/o cc.
he described exactly. to a "t" what my symptoms were/are,
its been acting normal lately. but this past saturday eve i went out to try some diff things, and it did it again.

still waiting to here back from the shop.
tuning correction seems to be the answer.

ToplessTexan

So from your post in another thread today, this is still an issue?