Trans. Code P0785 (Slipping in 1st) - Page 2

muzzy1maniac · #16 09-06-2005, 08:22 AM

Take it to Autozone for a free code read.

JCP0521 · #17 09-06-2005, 10:58 AM

Well, I replaced the ignition switch too. Still the same problem. I took it to Cottman to see what their diagnosis is.

BlazerLT · #18 09-07-2005, 02:16 AM

Was the tranny filter replaced at all?

awc109 · #19 09-07-2005, 06:25 AM

Filter changed little over 10,000 miles ago. Just seems electronic to me in that when I "reset" the computer by unhooking the battery that it temporarily corrected the problem. I'm 99% sure it resurfaced at the exact time I shifted it to OD. I'm going to retest the OD timing tonight. I'll keep you posted.

JCP - Any news from Cottman?

Allbert · #20 09-07-2005, 07:13 AM

Quote:

Originally Posted by awc109

Filter changed little over 10,000 miles ago. Just seems electronic to me in that when I "reset" the computer by unhooking the battery that it temporarily corrected the problem. I'm 99% sure it resurfaced at the exact time I shifted it to OD. I'm going to retest the OD timing tonight. I'll keep you posted.

JCP - Any news from Cottman?

Since you had a shift solenoid fault code in your computer and you've replaced all the solenoids (whew!$) and this issue still occurs, I wonder if there might be a wiring issue, like a partial short to ground. The 1-2 shift solenoid is energized in 1st, overdrive, neutral, and reverse though, so if there was a fault in that circuit, it would seem like all those ranges would be affected.

Good luck.

awc109 · #21 09-07-2005, 11:20 AM

JCP did all of the selonoid changes - I haven't dug into the codes yet (hoping to Autozone this weekend for a read). The wiring is an interesting thought though. I had a squirrel problem about a year ago. Darn thing chewed threw my main harness and I had to resplice 5 or 6 wires. GM doesn't give you much "extra" wire in the event of a squirrel attack.

awc109 · #22 09-07-2005, 04:50 PM

Scrap that thought - it's not limited to just overdrive. I unhooked the battery and it worked through all 4 gears just fine.

97BlazerDude · #23 09-07-2005, 08:05 PM

I can give you my thoughts on the scanner....I also have a 97 4.3L auto with 4x4 and the CE light comes on about weekly. The scanner paid for itself for me. I am just about to the point now where I keep the thing in the glove box!

BlazerLT · #24 09-07-2005, 08:28 PM

Quote:

Originally Posted by awc109

Scrap that thought - it's not limited to just overdrive. I unhooked the battery and it worked through all 4 gears just fine.

You should go and have it hooked to a Tech2 and have the computer relearn monitored.

Your main pressure solenoid could be faulty.

JCP0521 · #25 09-08-2005, 05:28 AM

Cottman says I need a rebuild, So I am having it done for $1500. They claim the fluid is leaking past the valve in the valve body and some of the internal componets are pretty worn (Springs and bearings). So this includes the updated valve body and everything else.

BlazerLT · #26 09-08-2005, 10:52 AM

Quote:

Originally Posted by JCP0521

Cottman says I need a rebuild, So I am having it done for $1500. They claim the fluid is leaking past the valve in the valve body and some of the internal componets are pretty worn (Springs and bearings). So this includes the updated valve body and everything else.

You mean the main pressure solenoid?

97BlazerDude · #27 09-08-2005, 06:02 PM

Quote:

Originally Posted by JCP0521

Cottman says I need a rebuild, So I am having it done for $1500. They claim the fluid is leaking past the valve in the valve body and some of the internal componets are pretty worn (Springs and bearings). So this includes the updated valve body and everything else.

Obviously Cottman knows more about transmissions than I do, but I just bought a new valve body with all new solenoids and valves and springs and spacer plate for just over $200. And you know what is involved with replacing the valve body as far as labor.

BlazerLT · #28 09-08-2005, 06:14 PM

To many trannies being replaced for no good reason.

They don't even really know what is REALLY wrong, just a theory and a $1500-2000 pricetag.

awc109 · #29 09-28-2005, 07:09 AM

I was reading the thread Blazee posted on common trans issues
http://www.automotiveforums.com/vbul...d.php?t=461182

Reading through the tech bulletin, I decided to check the voltage at the #24 fuse with the CEL out which read 12.87. Drove it to the end of the driveway - CEL illuminated and I lost 1st and 2nd. Checked the voltage again - it read about 3.5 w/ the truck not running. Started the truck - it was back to 12.87, and 1st and 2nd came back (CEL is still illuminated). These electronic tranny are a pain in the a$$. The 700R4's may have been crap, but atleast when they started acting up, you knew it was time for a rebuild!!

JCP0521 · #30 10-07-2005, 06:19 PM

After a month I finally got my truck back. Cottman rebuilt the trans., then told me it is still doing the same thing. Then they replaced the computer under the hood and that fixed the problem, $1775.00 later. but now my key gets stuck sometimes when I turn off the truck, the Neutral or Drive dosent highlight with the gear shifter but all other gears do, and sometimes when the key is removed the gear selector stays lit until you restart the truck, move the gear selector and turn it off again. Could this be the new ign. switch I installed or could this be from the linkage from the gear selector to the trans.

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