99 Explorer shifting problem, extra gear feeling

[shanes76]

on my 99 Exp. when Im accelerating from a stop, it feels like I have an extra gear between 1st and 2nd, but its a hard bump like feeling like someone bumped you , and I get this same thing when braking when it gets to 2nd shifting down to first . Transmission rebuilt 2 years ago. Also sometimes when going 30mph at a steady speed it will surge. I dont have no slipping or anything, shifts smooth other than that bump. On the braking part- it doesnt happen everytime. There is no clunk or jerk when I put it in gear. I can hear a noise in the rear like a metal rubbing noise- kinda sounds like brake pads though. Anyone have any ideas of what to check?

 

[gmanpaint]

You have a hard one to diagnose for me. Others may know exactly what it is, so keep bumping this thread.

Could be the Torque convertor is locking/unlocking when It shouldn't be. Is the O/D light on at all?

Could be a bad valve body or a bad solenoid. O/D light flashing at all?

Could be the VSS is bad and the trans is having trouble knowing what gear to be in. O/D light flashing at all?

When the trans is installed the T/C and the pump have to be lined up correctly or the T/C wont operate correctly.

Rear end noise can be either E-brakes, brakes, axle trouble, carrier/gears or limited slip clutch discs gone bad. Sometimes the rear end discs break apart and chunks of them fall in to the gears and get ground up.

 

[shanes76]

the OD light isnt on, it only seems to surge at about 28 - 30 mph when trying to hold a steady speed. The OD light doesnt flash either. It shifts smooth and and everything, it just has that extra bump like someone tapped you in the rear. And then upon slowing down to stop and sometimes when you come to a complete stop it feels like a bump like the rearend is catching back up to the car. On the rear rotors I dont believe they are working correctly because the rotor is not all shiny, it has some rust so the calipers may be locked up

 

[gmanpaint]

Time to crawl under the truck and inspect everything. Look at the rear axle mounts....leaf spring hangers....U-bolts....drive shafts....trans cross member mount pad....front end parts as well. If you cant find anything wrong externally, then you know its internal.

You have now stated the rear brakes twice, so start there and inspect them. Place the rear end on a set of jack stands, tires off, & have somebody depress the brake pedal, while you watch the rear calipers/pads for movement.

 

[shanes76]

I was trying to check prices on some of the items you mentioned, is there another name for the axle mounts?

 

[gmanpaint]

I was using the term Rear axle mounts loosely, eg...mounting plates for the U-bolts and shocks.

Leaf spring shackles/bushings are in the very rear, and bushings at the front of the leaf packs.

There is perches welded to the axle tubes that the leaf springs use to set them in place with a centering pin/bolt.

All of these work together to hold the axle in place.

 

[shanes76]

ok, Im going to check all that and put in new universal joints. Thank you

 

[my98nnj]

You never told us which engine and trans you have???

 

[shanes76]

it has the 4.0 SOHC and its an auto with OD, I put in a new universal today but it didnt fix it. The back brakes are working as well. Leaf springs and everything checked out ok. The tranny was rebuilt 2 years ago.

 

[shanes76]

could this have been caused by a bad vss in the diff? I replaced a universal that seemed to move a little but still have the bump

 

[gmanpaint]

When a VSS goes bad, the trans does not know what gear to be in. Since the ECM cant tell the speed, it does not know what gear it should be cruising in. When this happens, it will tell the trans to go into Neutral as a safety precaution.

Symptoms of a failing VSS is...Speedo needle bouncing up & down rapidly, then stopping all together....Trans shifting into a random gear, one after another in rapid sequence....O/D light flashing....Slipping into Neutral.

You should get a code for the faulty VSS.

Something else to think about...
If the tone ring in the rear diff is broken, teeth chipped, etc...the VSS can't pick up a proper reading, and act as if the sensor itself is bad.

I would tend to lean on the problem being in the trans itself, or the 4405 t-case, as these are more prone to fail over the diffs. Not that the diffs are trouble free, but they have less working parts to go bad on.

 

[shanes76]

the trans was rebuilt 2 years ago, I did have an ABS code C1102 and C1230 IT shifts great, I cannot get it to shift into 4X4 low though, the 4 hi light will come on but it wont go to 4low

 

[gmanpaint]

Can you explain your procedure to get into low range?

 

[shanes76]

I put my foot on the brake, shift it to neutral, turn the knob to 4low, I can get it into 4 hi and I can hear like 2 clicks behind my dash but thats it, no light, I even tried to put it into drive and move a little and it still wouldnt change to 4 low

 

[gmanpaint]

Alright, it's time for a test if your up to it.

Have someone you trust help you here. Explain to your helper the procedure you just told us (yes, you did it correctly) and let them handle that part. Meanwhile, you climb under the rig and place your hand on the shift motor on the T-case, and get close to it so you can hear whats going on. Now, you have to mind the helper and the exhaust so you don't get harmed doing this.

After the engine is running and it is placed in Neutral, with foot on brake firmly, Then climb under and ask the helper to shift from high to low range when your ready.

When it is switched from high to low, and back to high, you should either hear or feel or both the shift motor engaging. This is a simple test to check it.

Okay, after thats done, 1 of 2 things are going to happen here.

1) You find the shift motor working.

This eliminates the shifter and brings up other problems. (will get into that more later if needed)

2) The shift motor did not operate as supposed to. Kill the engine.

This does not mean its bad necessarily. The next thing to do is unbolt it but leave the harness plugged in. Start the engine, Repeat the test again with your helper and see if it works loose in your hand. Kill the engine.

If it does work loose, there might be a problem with the t-case, or the shift motor is weak.

Next test....With shift motor off ( ziptie it to the frame with it still plugged into the wire harness for now). Use a pair of simple pliers to move the shift rail that you see coming out of the t-case that the shift motor covered. Notice the markings. You will see H-N-L. That triangle looking nub points to what position it is in. It does not turn in a full circle, this is important, it will only turn to the H & L position and not beyond. Start the engine, place it in Neutral. Have your helper gently rock the rig front to back, as you turn the shift rail to ease any pressure off the drive train. Turn it from H to L, but don't force it past. It will click when its in gear, and stay.

Okay...did it shift?

Yes...Great! Tcase is most likely good.

No....Bad news. T-case is most likely broken. This can be a cheap fix or an expensive fix. No telling until the case is split.

Hopefully you don't have to go thru everything here, but just in case, I went ahead and told ya so in case I don't get back to you for awhile, you have something to mess with.

 

[shanes76]

wow, thanks for all excellent info and I'll be tackling this job this weekend and I'll let ya know what I find or dont find.

 

[muhl5443]

sounds to me like you have a sticking valve in the valve body of the trans. mine did the exact same thing. even after my trans was rebuilt.

 

[shanes76]

is there any way to tell? about what would it cost to fix? or how would you fix it?

 

[shanes76]

do you think some Marvel mystery oil would free it up?