97jeepxj40

Hi all

Last week, all 3 solenoids were changed in my AW4 after getting codes for shift solenoid B. Figured I might as well change all 3.

For the last few days the Jeep has driven better than ever, shifting exactly when it is meant to, and I can barely feel the shifts. Massive improvement over what it was like before, getting stuck in gear etc.

I went out to the shops today and it was still great, however I tried pulling onto my driveway when I got back - up just a slight incline, but there was no power in drive! I put the Jeep into reverse and it backed up just fine. Tried again to get onto driveway, no joy. The engine revved up but didn't move.

I parked it up and went into the house. I had a quick search on CF for anyone else having a similar issue and the responses were mainly to check fluid.

Since the gasket was replaced whist the pan was off, I checked the fluid. The level was fine, and looking nice and red.

I started the Jeep, and went out for a quick drive and it was fine, plenty of power and shifted like new. I came back, and drove onto the drive as normal.

What could have caused the Jeep to not move in drive - just once after a trip out? I'm lost...

CCKen

The next time it does this, stop and shift through all the gears, ending in D gear. If it still slips, select 1-2 gear and see if moves.

The Transmission Range Selector (NSS) may be boarder line.

97jeepxj40

Hi CCKen... Thanks for the reply.

The Jeep will be doing its daily 40 mile drive tomorrow so I will certainly do this if it happens again.

Why would the nss make 'drive' behave like it was disengaged?

If it helps any, the nss has never given any signs of imminent failure... Always starts easily and reverse lights always work. Got to admit... That's pretty much where my nss knowledge ends.

CCKen

I'm not saying it's definately the NSS failing but you can see in the attached diagram of the '97 Transmission Range Switch (NSS) that the switches in the NSS serve to tell the Transmission Control Module (TCM) what gear you've selected and what it should do concerning the electronic shifting of the transmission. If you selected 3 gear, the TRS will shift through 1-2 until it got to 3 then will not shift to 4th gear (D). Same with 1-2, it will only shift up to 2nd gear and will not shift to 3 or D.

If no gear is reflected as being selected the TCM will go dumb.

Park (starting) and reverse are only two functions of the NSS.

97jeepxj40

Ahh perfect! That helps a lot thanks very much.

I sure hope my trans isn't toast.

CCKen

My Dad was born/lived in Brummagem England. I visited there in 1984.

Do you live near Birmingham?

97jeepxj40

I'm about 120 miles away from Birmingham.
I guess he must have been used to the wet weather

97jeepxj40

Ok. Drove the Jeep to work this morning. At first it seemed a little sluggish. I seemed to have to apply more gas than usual to get it up a hill. After that it seemed ok. I'm sure that when I apply more gas I can hear the strain on the trans as I think it whines a little, although I may be imagining that.

CCKen

Sounds like its slipping.

What brand (Type) transmission fluid are you using?

You did check the fluid level like I outlined above didn't you?

97jeepxj40

I have used Granville ATF D3 in the trans when the solenoids were replaced. It had another drain/refill the week before the solenoids were changed with the same fluid. I'll see if I can post a pic of it.

I did check the fluid level last night and it was a hairline below max with engine running/hot and I had cycled through all the gears. Maybe I read it wrong. Each time I move the Jeep I have checked for puddles on the floor but nothing was there. I suppose it could only be leaking when under load though if it is leaking.

I'll check the level again.

I can't believe it can go from running beautifully to this in such a short space of time.

CCKen

I see that Granville ATF DIII is a Dexron III ATF, but I can't find that it has a Mercon content, like the FSM calls for (Dexron III/Mercon).

What do you mean when you said previously that "when I apply more gas I can hear the strain on the trans as I think it whines a little".

Are you sure its not the engine lacking power?

Edit: Is the trans dropping out of overdrive when you go up a hill?

Is it downshifting?

If you suspect it is still in overdrive, tap the brake pedal and see if it drops out.

97jeepxj40

Ok here is the fluid. It does say mercon on it as I was careful of this and paranoid about getting the wrong fluid. There really isn't much choice of D3 over here.

97jeepxj40

When I said I could hear strain, it may have been just me over thinking it, but I could just tell something wasn't right. I'm fairly sure there was a light whining noise coming from the trans tunnel...

The engine seems fine. Runs great and there is plenty of power.

I'll see how it performs on the way home again. I'll have to warm the Jeep up first and check fluid again before I set off.

CCKen

I did edit my previous post to talk about overdrive. Check it out.

97jeepxj40

Ahh sorry I missed your edit.

No, the trans is downshifting fine when it needs to.

I did have a faulty tps last week too... The Jeep was downshifting on main roads doing 50+ mph if I moved the throttle at all, either putting gas on or letting off. It was a nightmare. I swapped the tps and it's been fine ever since (apart from now that is). So... It was downshifting a lot last week. I omitted this from my first post as I didn't think it was relevant. Maybe it is.