Trans problem; won't go into gear?

[duckmanjbr]

This is a repost of a reply I already put in a diff. thread but thought it would be better off as it's own thread so...... I'm sorry for the double post!

Here's the deal - 02 LS1 motor and trans w/ 4L60e, NP harness and tune. The truck ran good for 200 in town miles over a few days then the trans just stopped. No clunk, no bang, no noise at all; just no more go. It seemed as if the trans pump stopped working and just wasn't supplying pressure to the valve body to change into gear. One minute the truck is driving down the road (grandma style) next min. the RPMs just go up like the TC isn't locked. I thought pump because even w/ a bad TC I would still feel a little something as I'm changing through the gears from park to rev or drive right? Also I saw a P1870 code once and had a few hard shifts so the bad pump made a little since to me.

So easy fix right.... replaced the TC and trans w/ a known good out of my friends car. Works great, no more hard shifts and no codes. Get ready, here's were it goes down hill...... at 230 miles of more in town driving over 3 days it's dead again! I leave the house today and made it 1 block and it's dead! The 1st time I was thinking maybe a heat thing or something but this time it only made it a block! I pushed it home! Thats how close I still was! To me thats not a heat problem at all! I checked fluid... good color and good amount. Hell its brand new so the color should be good! At idle the fluid reads good, maybe just a tad on the high side but good. With the truck off it reads way high. Like and inch over on the dip. To me this means the pump is working right? Lower fluid level when running? So now I'm all confused! I'm thinking the pump is good but it's the exact same as before. No gear works and you can't even feel a little nudge or idle change when changing through the gears so once again i don't think there is anything working in the valve body. How much of the trans is controlled from the PCM? Allen at NP was nice enough to send me 3 PCM's due to other problems getting it running and now this being the 3rd runs good but I've put a little over 400 miles on the motor and will be replacing the trans twice. There has to be something else going on! 1st trans was never taken apart. 2nd trans was easy enough swap. VSS, C1 plug and a few bolts done. It's not the 1st trans I've ever done! I'm starting to go a little crazy but I don't think it's anything I'm doing wrong. I'm leaning hard to a PCM or a wiring problem? I thought buying a harness would save me the problems but here I am........ Do I need to sync the trans or something else crazy kind the CamPS and CrackPS? Anyone ever seen this?

BTW here's a pic of the install..... if I could get it running for more than a week i might be able to put some time into making it look good!

[casey23]

You did good checking the fluid to see if its pulling down ... most of the time if the level looks good running and you turn it off it will rise 2" or more up the dipstick... was it dead on before and now its over? or do you really know... stupid question but was there something weird about bolting the converter up? did you have to pull it forward a long ways to meet the flywheel... Its really weird that it happen to two units.. not sure what else you swaped ( prindle,sensors ) but for the most part it should do something unless something is wrong with the pump.. if it worked for 2 miles there is really not another reason it should just stop... My guess is something wrong in that area and the conveter is pulled out of the pump to far and caused some type of problem... since u said the fluid still looks nice and red.. if you had a stopped up cooler it can trash one pretty quick.. but you can see that when you inspect the fluid..

[casey23]

did you drop in the ls1 in with your old trans and flywheel? or new trans and flywheel that came with the motor as a package... or were they bolth from different cars? ... or same trans and converter you truck came with but installed an ls1 in front of it? ....

[duckmanjbr]

The 1st trans was a package deal w/ motor and was NOT removed from the motor when it was installed. It was all one piece taken from the doner Z28. The 1st trans was all factory when I pulled it apart to put the second trans in so I don't think it's anything about the install of the trans. The second trans was a bone stock trans and had no problems at all while it was being installed(once again Z28 doner). Nothing weird about bolting it up and no problem w/ the TC that I could tell. The TC was a little hard to spin by hand when it was slid on but I didn't think anything about it and just thought that was normal. It was a nice fit over the trans shaft (no wobble)and I replaced the front trans seal when I put it in. All in all was a very easy swap w/ no problems. I really can't say more about it. I'm lucky enough to be doing the work in a full garage so a lift and trans jack make it for 1 simple and quick change! As far as other things changed, just the trans, TC, fluid and the VSS that was in the new trans. I didn't see a point in reusing the old VSS when the new trans had a working one. Thats it! The whole swap from start to finish took less than 2 hours. The nuts and bolts part isn't really brain science you know? Thats why I think its an electrical thing. I didn't dive at all into the harness or wiring part of things in the trans because it's all from NP so I think thats where I'm going today. I'm gonna test out the cooler and make sure I got fluid transfer through the cooler and then I'm gonna start shooting wires to the trans. I'm really gonna be pissed if it's a wiring thing.

[duckmanjbr]

Well I know how this site loves answers to all the problems so here's what I found... I disconnected the cooler lines to make sure I had fluid pressure in the trans. Nothing.... I guess the ole dipstick check isn't very accurate to see if the pump is working. With the motor running and it in park I get no fluid being pumped to the trans cooler. That makes my problem simple right? Bad pump? I'm still a little weirded out that I've lost 2 pumps in 5 or 6 days though. I flushed the cooler to make sure there were no blockages and make sure it was good. So now I'm left w/ nothing other than a bad pump. What would cause 2 bad pumps in a row other than my extreme bad luck? Does it make a difference what cooler line gets connected to either side of the cooler? I guess my next test will be w/ a new trans and make sure I'm getting flow through the cooler then.

[RedHeartbeat]

Did you service the filter while you installed the transmission? If so, was it black plastic top half with a metal bottom half? Did you replace the seal that goes into the pump? If not and the old one was damaged you could have been sucking air. When dropping the pan you also could damage the shift solenoids and you'd lose motion. Finally, get rid of the EPC solenoid and replace it with a Transgo vacuum controlled shift modulator!

[duckmanjbr]

The pan was never dropped! I didn't do anything internal to the trans. I've been calling around and was told to check crank play and make sure the flywheel is straight. I'll be doing that later today or tomorrow. I didn't do anything in the trans so everything should have been stock. I have a brand new transgo shift kit in the box sitting here on the bench but I'm not putting that in until I can at least get the thing running. The plan was to put a few weeks on the motor and trans before I start doing big mods. Good thing I made that plan! I'm all stock motor and trans other than headers (needed to fit the truck) and pulleys and I'm having all kinds of issues! 2 bad trans and now maybe bad crank play causing the trans to go....

[RedHeartbeat]

If the thrust bearing is out on the crankshaft you're going to need a new engine before long, most likely. Contact whom you bought it from if that is so. Put the Vacuum mod kit in the transmission and you'll bypass any problems with transmission fluid pressure. Just follow the guide, it's easy to do.

[duckmanjbr]

Red,
Ive been reading about excessive crank play causing pump problems. What is the easiest way of measuring proper clearance to tell if the thrust bearing is bad?

[casey23]

if it moves enough to see with your eyes i am sure thats to much ... I have never seen that problem on a chevy truck... but most times conveter/pump clearance is .060-.125 1/8" is a ton !