I just rebuilt entire tranny lost the reverse band rebuilt complete by my tranny shop got it out on the hwy and everything seemed great 2 weeks later I am driving to work in OD and the truck hits 100KM and it really starts to shudder and lurch..I ease of the gas and gone than accellerate again and same speed shudder....(Very cold morning but truck had been on the road 1/2 hour before this happened) The next morning very cold leave my driveway get 200' down the road and the truck starts to buck and shudder looses power than recovers and alls well...the tac was showing the truck was revving but it was not accellerating ...on the HWY agian this time at 95KM I get the shudder like it was jumping out of gear almost....I took the truck back to the tranny shop his called tonight when I was out told my wife that it's an engine thing not the tranny something about a code 586 and a module on the firewall being very sensitive to cold or wet weather...I recieved zero engine codes during any of these problem times ....any ideas as to what he's talking about thanks..Thesmoke

Take it back to the tranny shop.

Thats were it's at and he is saying the tranny is giving no codes and is shifting smooth but his computer pulled out this 586 code which he says will not give an engine service light but it's an engine code from this firewall mounted module?

586 code? Firewall mounted module?

Did you relocate your IP?

I looked up that code, no such thing, I even tried P0586 incase he wrote it down incorrectly.

What is that guy smoking or what scanner is he using? 1994 trucks have a OBD1 connector. You can read the codes from the SES light. There is no 500 series codes for a 1994 truck that even exist. I would go get the truck from him quick before he burns up your computer with his scan tool.

Once you get the truck from that idiot try some of this stuff.

Run the checklist and you might find your problem. I would check to make sure your OPS and lift pump are working properly, all your battery connections are good, your grounds are good, make sure your fuel filter is in good condition, make sure there are no fuel leaks and no air in your fuel system. If all that checks out then I would suspect a PMD

OBD-I only has a two digit code... no such thing ever listed about "cold" that I've ever seen on here. Fluid level okay? Service engine light ever come on? May want to check for engine codes with paper clip just to see what's up... see FAQ's for more info on code reterival.

The only thing re-located was the PMD which is mounted on aluminum heat sink and extension cable at rad....have all the newest updates to my Injection pump...Thesmoke

PMD doesn't sound suspect by what was described... got a video clip maybe of this happening? Does it happen regularly? Engine "revving" does not seem to me an idicator of an engine problem. Sounds like lack of load if it rev's. aka, tranny not getting the job done down to the road way maybe?

Ok great ideas...I was thinking fuel filter also but why could I get it to repeat at same speeds in Overdrive....all my battery stuff I just redid (kinda anal that way) with grounds....no there was no engine service codes ...I do know that I am about to do some front end work but waiting till the polar bears get out of my garbage cans:D....very cold right now...2 inner tie rods...1 outer tie rod...but that should not cause this it seems like the tranny was jumping in and out of gear or slipping...today it was warmer and it did not act up on a 1/2 hour trip to the tranny shop...Thesmoke

Something else my wife mentioned he said I do have bad cold start issues which I need to re-check all my glow plugs then follow the flow chart he said this sensor problem maybe causing the cold start issues also..I will be calling him first thing tommorow morning...Also tranny fluids were fine

I feel fortunate I have never had a shop rebuild a trans yet. I hear horror stories like this over and over and trans shops NEVER want to admit they screwed up by skipping about 21 steps in the the 30 step rebuild process. I hope it is something else but sure sounds like your trans pump is weak and not holding pressure and causing irratic motion and slipping.

I really think this should be one of the datline under cover things. People get screwed out of work wages, more money, time, etc because so many shops just fix what is broke and call it a "full rebuild".

I am also STRONGLY against this little "trans flush" they do at small service centers. nothin like grabbing that sludge on the bottom of the pan and pushing into the valve body. If your filter was flowing before, it sure won't after trying to catch all that funk that they stir up. K, I am done now!

No kidding Viper with that tranny flush thing lets all plug the filter....This tranny guy I know and he's been doing GM stuff like mine for years...but hey who knows maybe the helper did something while my guy was looking at another job...my father in-law is an old diesel guy he said to check the high pressure lift/fuel pump it could be failing at higher demand then correct itself which may explain the loss of power also and sudden loss of fuel pressure would cause bad shuddering of the engine ...or he said my guy screwed up something in the torque phase of the re-build...One other tidbit my father in-law mentioned was since today nothing there may have been some shit floating around that got stirred up with the re-build and it got passed through...Anyway some great ideas to follow up on..Thesmoke

Something else my wife mentioned he said I do have bad cold start issues which I need to re-check all my glow plugs then follow the flow chart he said this sensor problem maybe causing the cold start issues also..I will be calling him first thing tommorow morning...Also tranny fluids were fine

With the cold starts and the trans acting funny, you may want to check out the ECT sensor. Its located in the coolant crossover next to the thermostat. Just an idea.

when my tranny was rebuilt the first time by gm dealership in south carolina, i kept having what i call down shifting. the truck acted like it would shift down a gear and the rpms would shoot up high and seem like it had no power at all, they looked at it several times and never fixed the problem . Rincon transmission told me over the phone it was the wire harness ground . he fixed for me and never had that problem again,
check the tranny harness.

When I had my transmission rebuilt in my 95 my tranny mechanic is my friend the 4L80e and 4l60e are electronic transmissions hence the E. There are some sensors and electronic parts and some connectors, my guess is that something possibly has a loose connection. My mechanic replaced all the sensors and did some re-routing of the wires to insure that I would not have any problems for along time to come. Some of the wires are located pretty close to the exhaust and if they didn't take care it is possible something could have gotten hot or even melted. You might want to have a look at the wires down there and make sure they have every thing connected good.

Well here's were I'm at the tranny showed zero problems but the computer when monitored the tranny for codes picked up that at 1/2 throttle tranny showed 50% but at the engine end it was showing TPS 22% and this was always fluctuating but the engine side was always way off...586 was not a code but a GM Tranny bullettin number..LOL...anyway my GM mech said that the main power module is mounted on the firewall right beside the steering column he said that all the windsheild washer fluid drains right down on that module he said to pull it off and he bets it all green and corruded all hot wiring harnesses go there so that is going to be fully checked Tues....he believes that is what's causing all the electric problems and maybe coldstart issues...Thanks for all your help I will keep you's updated...TheSmoke

Something else my wife mentioned,.. he said

wow,. i knew it was legal in ontario,...:rolleyes:

nick