I have a 94 SLS w/ the 4.6 N*. This problem has been going on for as long as I can remember now (prob. a year or two atleast). My car cranks great, idles smooth, no codes. Most of the around town driving I do is around 45 mph or so. If i put the car in OD (overdrive or 4th gear) while im driving and just barely give it a little gas (at or around 40-45 mph) it wants to huckle buck or jerk. If i give it more gas to speed up it accelerates great. I have been driving around town with it in 3rd gear to try to reduce this but it still does it a little bit (and it does this in 3rd gear just as much at lower speeds). Is this something wrong with the tranny (maybe a shift solenoid or something or worse....gears?) or could it be fuel supply related? The car has about 119K miles on it. I bought it with 82K but have not changed the trans. fluid & filter yet. I know it wouldnt hurt to do this but I wouldnt think that the trans. fluid would be the culprit. Any help or ideas would be greatly apprecieated.
01-14-04, 10:24 AM
Have you ever had the engine tuned?
It sounds more like a misfire to me. Bad plugs and /or wires will cause this.
You think it would misfire under heavy throttle more but it is under a heavy load when in the circumstances you describe.
First thing I would do is put in new plugs.
Changing trans fluid isn't a bad idea but should be done a lot sooner/more often to extend trans life. In other words, good idea to do it anyway.
01-15-04, 12:24 PM
Much more likely it is the shift solenoids, specifically the shift solenoid for 3-4. There is a bit of history of the shift solenoid plastic casing cracking at high miles and starting to leak/prevent full actuation of the gear select. There is a service kit for replacing the shift solenoids on the 4T80E that includes a retro-fit brace for the shift solenoids to make the mounting more robust and eliminate the case cracking issue.
This is a relatively simple and straighforward item to repair. The shift solenoids (2) are in the bottom pan and easily accessible by dropping the bottom pan with the trans in the car. The lower valve body does have to be removed from the trans and split apart to R&R the shift solenoids but, as this is done on the bench, it is also relatively straight forward. There are many reports of folks doing this repair themselves on the caddyinfo forum and is well within range of the average DIY mechanic if you are familiar with engines and transmissions. Having it done in a shop is straightforward. Parts are likely in the neighborhood of $100-150 and labor would be around $200-300 I would expect. Parts and a couple of hours of time would be the extent of it.
See the post about transmission flushing (don't do it) as you will be tempted by the shop when they do the solenoids. A Cadillac dealer is very familiar with the shift solenoid replacment and the service kit.
hey, i really apprecieate the info. right when i bought the car (about 2 yrs & almost 40K miles ago) i replaced all plugs & wires, air filter, & fuel filter with oem parts so i wouldnt think it should be anything related to that. i will go ahead and replace the shift solenoids and see what happens. i normally do all of the work myself but i must admit, im not a professional. i got my hands on some mitchell1 software so ill check with that also. thanks again guys.
ok, one more thing. i just ordered the valve kit #24211355 from gmpartsdirect. it only costed like $43 or so. i was searching around for some more install info. and found this http://caddyinfo.netgetgoing.com/howto/pc0717.htm
there are a few pics on the page and in them i can see the two solenoids at the top right. it looks like all i will have to do is remove the trans. pan and there they are. is it that simple or will i have to remove something else too (ie a cover)?