Shifting problems

JA no Y · 09-10-2005, 05:53 PM

OK...I've done a search of all the shifting problems ppl have had but I couldn't find any like mine.

I had a wheel speed sensor wire that got cut by my wheel. ABS light came on of course and my transmission started acting up. Figured it was due to the speed sensor. Replaced the sensor and got the codes remove at a shop. Tranny still acting up. No SES light or ABS light. Tried to see if there were any codes, none could be detected.

The problem I am having is that the tranny will shift through 1st and 2nd, but have to "play" a little with the gas pedal to get it to shift into drive. There is no Over drive at all. Just will not shift into OD. When I get up over 20 MPH and at a "cruizing speed" it feels like it downshifts into 1st or 2nd cause the engine will rev up extremely high b4 it feels like it is in any gear at all.

The tranny has a new filter less than 4 weeks and the fluid level is up to operating levels. Problem started almost a week after filter and fluid was changed.

Any clues?

BlazerLT · 09-10-2005, 09:46 PM

Ever changed the fluid?

JA no Y · 09-10-2005, 11:07 PM

Complete flush when filter was changed.

BlazerBoyLT98 · 09-11-2005, 12:36 AM

Is the tranny fluid at the correct level?

JA no Y · 09-11-2005, 01:10 PM

Quote:

Originally Posted by JA no Y

The tranny has a new filter less than 4 weeks and the fluid level is up to operating levels. Problem started almost a week after filter and fluid was changed.

Yes...the fluid is up to level and had a complete fluid change when filter was replaced.

BlazerLT · 09-11-2005, 05:41 PM

sounds like the main pressure solenoid is not keeping line pressure high enough.

JA no Y · 09-11-2005, 08:11 PM

Main pressure solenoid? Is that the same as the on/off shift solenoid? I have read there are 1-2, 3-4, and 3-2 shift solenoids but when I went to get a shift solenoid from Advance Auto they only had the on/off shift solenoid. If its not the same I guess I'll have to wait for the dealership to open tomorrow.

Also....anyone have a picture or a diagram of where the differant solenoids are located. Last i had the pan off I don't recall any markings or little arrows with signs labeling what was what. And the Hanes manual doesn't go very in dept on about the transmission.

Jeremy Fitch · 09-11-2005, 09:12 PM

Quote:

Originally Posted by JA no Y

Main pressure solenoid? Is that the same as the on/off shift solenoid? I have read there are 1-2, 3-4, and 3-2 shift solenoids but when I went to get a shift solenoid from Advance Auto they only had the on/off shift solenoid. If its not the same I guess I'll have to wait for the dealership to open tomorrow.

Also....anyone have a picture or a diagram of where the differant solenoids are located. Last i had the pan off I don't recall any markings or little arrows with signs labeling what was what. And the Hanes manual doesn't go very in dept on about the transmission.

This should help you a great deal.

Allbert · 09-12-2005, 07:30 AM

I work at the plant where we make the pressure control solenoids, and I can tell you that the overwhelming majority of the ones we get back for warranty analysis are actually good parts... they're just easy to get to so techs swap them out before looking for the real problems. If you're problem started just a little while after you changed your fluid and filter, there's a chance maybe the filter or metal clad seal were not installed properly and might be letting air get sucked into the system. Were there any issues at all that prompted you to change the fluid and filter in the first place, or was that just for routine maintenance?

One more thing... the resistance of the PCS is supposed to be around 4 ohms at 20C... higher when hot, of course.

JA no Y · 09-12-2005, 11:44 AM

I changed the filter and fluid as routine maintenance. I didn't know when the last time it had been changed and the fluid was starting to get darker. Wasn't brown or black just time for a change. Better safe than sorry. Thats why I did a complete system flush with new fluid. It drove fine untill I had a problem with the ABS wheel speed sensor. Once I fixed that, the problem remained. I'm not sure if it has anything to do with the ABS system or not. Thats why I posted this thread. Just wanted to see if there was anything other than a rebiuld or replacing the tranny I could try. I have 1st, 2nd, and reverse. No slipping in those gears at all. Just when I get up above 20 mph does it start to act up. Feels like it doesn't want to shift into 3rd but downshifts back to 1st and the engine revs up. Have to play with the gas pedal to get it to finally shift into 3rd but it doesn't stay there. It will stay in 3rd only if I'm trying to gain speed or going up hill. Long as ther is a "load" on the tranny it will stay in 3rd. But it feels like it shifts back down to 1st or 2nd if the load is taken off the tranny.

Any advice will be greatly apperciated. This is the only vehicle I have on the road at the moment due to the fact that the tranny in my 88 is totally fooked. (thats what I get for buying a used one from someone I don't know)

JA no Y · 09-13-2005, 10:59 PM

I spoke to a tech at the local dealership about my tranny problems. To no surprise he sugested I have it checked for codes. I told him I had just had it checked by my "go to mechanic" (the mechanic I use if I can't fix it myself) and there were no codes. So he sugested then that I have it checked there at the dealership. I understand they will have more diagnostic equipment there but he didn't even hint at what could cause the problem. Just that I should bring it in to have it checked. All I wanted was some advice as to what it could be. But nothing. When I asked about maybe a shift solenoid he looked surprised I knew what one was. My mechanic told me flat out that he had no clue without actually working on it. Least he was honest about it. All I got from the tech was that I needed to bring it to him to have him run tests on it which will cost me out the arse. And I wouldn't be surprised if it needed rebuilding or replaced.

I just want some ideas as to what could cause it. If all it is is a shift solenoid...which one? What else can I check before I break down and just have it replaced or rebilt? Any advice would be greatly appreciated.

JA no Y · 09-17-2005, 10:48 PM

Well...I went and got 2 shift solenoid to see if thats causing my shifting problem. Now I have a question. When I removed the 1-2 shift solenoid retainign clip, the "plunger" behind the solendoid pushed the solenoid out. But when I removed the 2-3 solenoid retaining clip, nothing. Plunger didn't push solenoid out at all. I pushed the plunger in a tad just to see if it would spring back out but it didn't.

My question is....Do both shift solenoid plungers have springs on them or does just the one?

blazes9395 · 09-18-2005, 01:26 PM

Quote:

Originally Posted by JA no Y

My question is....Do both shift solenoid plungers have springs on them or does just the one?

Yes they do, but its a different design, or setup inside the valve body, so the piston will not pop out like the 1-2 did....at least you know the 1-2 is not sticking and working properly.

Allbert · 09-19-2005, 09:27 AM

Quote:

Originally Posted by JA no Y

Well...I went and got 2 shift solenoid to see if thats causing my shifting problem. Now I have a question. When I removed the 1-2 shift solenoid retainign clip, the "plunger" behind the solendoid pushed the solenoid out. But when I removed the 2-3 solenoid retaining clip, nothing. Plunger didn't push solenoid out at all. I pushed the plunger in a tad just to see if it would spring back out but it didn't.

My question is....Do both shift solenoid plungers have springs on them or does just the one?

Schematic from the GM tech manual shows no spring behind the 2-3 shift valve.

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