USMC Sniper

Hi guys,

New here and should offer the disclaimer that I am not a mechanic, but an industrial electrician. My experience in mechanics is limited to a few starters, head gaskets, radiators, and other small bits. I have never worked on an automatic transmission.

So here begins the story....

I have a 98 Chevy C1500, with a 5.7L, 4L60E transmission. I notice at highway speeds the trans feels a bit like it is slipping, and the "Service Engine Soon" light comes on steady.

I took the truck to my local Autozone, and the code given was Shift Solenoid A Electrical. So I did a bit of basic research, and felt comfortable enough to change the shift solenoids, which I have now done.

I reset the light by disconnecting the battery for a time (while I changed the solenoids), and it came back on almost immediately.

The New code is exactly the same. Shift Solenoid A Electrical.

I checked all the wiring, and all looked just fine. So I am a bit perplexed at this point.

The truck seems to be shifting just fine and is not shifting rough, however it does still seem to have that slipping feel at highway speed, and that light is back on.....the light does not bother me much, but, my wife nagging about the light does.......yeah, welcome to my life lol.

Anything I can look at myself? And advice you guys might offer would be much appreciated.

Thanks a Million, and great site guys,

Mike

Brian68

How far do you want to go in this? I assume it set a P0753, and the solenoid usually fixes the higher milage codes. You are left with two faults. Chaffed wire between the PCM and the solenoid, or a PCM, and those PCM's hardly ever smoke. Disconnecting the battery usually won't clear codes from about 1996 up, so a trip to the parts store to clear it may help.

Slipping on the highway like you back out of the throttle and when you get back to float (maintain speed) the RPM's go up then right back down once, until you back out again? That is normal torque converter operation. Slipping fourth is different, and needs repair.

Thanks for your service.

USMC Sniper

Yes the code is P0753. I did not know that disconnecting the battery would not help, it did seem to keep the light off until the first time the truck was driven. Before I disconnected the battery, it was on all the time. I will take it to the store and have this reset.

At highway speed, say around 55 it just feels like it is missing. It jerks a little but the rpms do not seem to move much, its very quick and then seems to smooth out at about 60 or so, then it may or may not do it again. Its rather odd to try and explain.

I think the trans is a 3 speed but I am not sure. I think the solenoids were listed as a being 1-2 and b being 2-3. I really dont know that much about it.

The service was wonderful, quite an adventure and I feel honored to have been able to do it!

Thanks for your help and I will take a look at the wiring and such....but...I may be in way over my head here!

Gilbert@Ace Racing

If it does not misfire at slower speeds or under a heavy load then I would suggest that the torque converter lock up clutch might be slipping. What was the fluid condition when you took the pan off of it?

If you were to take the positive battery cable off the battery and hold it on the negative terminal that should bring the memory capacitors in the PCM down which will reset all the adaptive memories as well.

As far as the code... a defective solenoid can cause the fault. So I agree that was a good place to start, but if that tranny is original then I would say it may have other issues.

g

Brian68

The '98 motors had a different kind of injection system, and that is probably your misfire feeling at highway speed. Sometimes you can clean them, sometimes it is too late. Usually they clog at the pintle, but yours sounds like a injector coil beginning to short. There is a GM updated injection harness kit that changes the engine to MFI, improves driveability and power, but it is pricey and this is your excuse to drop in a LSx motor. Part numbers 93441235, 17113206, 93442096 if you go the MFI swap route.

The trans code won't be helped by the MFI swap, but could be by the engine swap. Since you have electrical wiring experience, take your DMM that is set to min/max resistance and put one lead at the trans fuse harness side (after the fuse element) which is next to the drivers door, and the other to the PCM red connector pin 6 light green wire. Use the smallest lead adapters you have to keep from bending the terminals, and they bend easily. Then watching the DMM, shake the harness and try to find an open. The reading on the DMM should be close to 22-30 ohms. After that, move the fuse lead to the battery or engine ground and do the same shake again to find a short to ground. Or just get a new 4L65e, 4L80e, 6L80e from Gilbert to go with the LS engine. The wife will understand when she rides in the new and improved truck.

BTW, 4L60e is a 4 speed, Longitudinal mount, 60 series, Electronic control transmission.

Ryan Schwake

if your light is still on turn your key to accessories and the second you do that press the gas pedal 3 times repeatedly than turn it off let it sit for about 15 seconds and your light should go off