Slow shifts out of first, flashing OD light

[HobokenMikeJ]

1999 Mtneer 4.0 SOHC 4x4. 158000 miles. A few weeks ago, it started doing a thing where it would occasionally free rev in drive unless you put it in 2nd or neutral and back in drive. At that point, I checked the transmission fluid, and it was about a quart low. I topped it off and forgot about it.

This past week it started doing that again, so I checked the transmission fluid level again, and it was fine. I dumped in a can of Transx, and figured it might just be the cable out of adjustment since bumping it into neutral and firmly back in drive solved it for that trip. I also tested engine braking, and it does not have engine braking in 1st, but does at speed if you turn off O/D. Reverse works fine.

Now it's taking a long time to shift out of first (seems to be at least 3k RPM's at the minimum) and, after a few of those, it takes off in 2nd and the O/D light flashes. I'm sure this means there's a code, but of course my Bluetooth OBD adapter doesn't read those.

Based on the symptoms, does this seem like something involving dirty internals/solenoids that could be addressed by using a cleaner in the transmission, or does it sound like something more serious? I can't afford to have the thing rebuilt (or even replaced with a junkyard transmission) right now, so if there's anything I can do to extend it's life at this point, it would be great. Up until tonight, when it started the slow shift out of 1st, it shifted fine, no delays or flares.

Thanks for reading.

I am have the exact same symptoms you described. Did you ever find a fix?

 

[Robman]

Use full synthetic tranny fluid when it's time to fill it back up.

 

[HobokenMikeJ]

Use full synthetic tranny fluid when it's time to fill it back up.

Thanks!!!!

 

[gatzdon]

Wish I saw this thread when it was first posted.

Forscan can pull all Diagnostic Codes from the Powertrain Control Module and Transmission Control Module (and all the other modules too). These are not the same as OBD codes you get from the autostore. If the OD light is blinking, there's a DTC in the PCM or TCM related to the transmission.

Most likely, there will be one code that stands out as the root cause. If you are lucky, it's something simple like "Shift Solenoid [X] Intermittent Failure" where X is the solendoid letter. Solenoids can be replaced just by dropping the pan, you don't even have to remove the valve body.

The cheap $10-$15 Bluetooth OBD Adapter can probably pull all the codes, but I recommend a good one like OBD Link MX Bluetooth which runs about $80 on Amazon. Forscan is free for the PC, about $5 for the phone.

 

[Wrath]

The OD flash has come to me now. Transmission runs fine when first started, within a minute shifts become slow/soft until I rev the engine. Just rebuilt this transmission a week ago. Pulled fluid pan, fluid looks good? Opinions? (See pics, bright red container is fresh from the bottle, slightly darker is from transmission.)

I have a spare valve body assembly complete with solenoids if i need it. About to go under and test the solenoids in the transmission. Would be better to just change solenoids, or swap out entire valve body assembly?

 

[Wrath]

Update: EPC solenoid in the transmission is inaudible. Removed from VB and tested again. It's operating, but is so soft the spark from the wire touching the terminal is louder. Compare to the EPC from the spare, which is crisp and so loud I can't hear the spark. Replaced with the crisp unit, and replaced the TCC solenoid as well since it's a similar type and I'm already in here. Will update with road test results soon.

 

[Wrath]

Update: definitely an improvement, but it won't engage drive or reverse unless I bring the revs up to 1200 rpm. Also need to rev to start going again from a full stop. OD Off light is flashing again. Does anyone know which pins I need to short on the test port to make it flash out the code? The links I've seen posted on how to do so seem to be dead, and only take me to an admin login screen.

 

[C420sailor]

Code reader that can pull trans codes.

I think you need to check line pressure. Sounds to me like either you’ve got a leak somewhere, or the pump isn’t producing enough pressure

 

[Wrath]

Would that connect to the port (I think near the back) with a bolt in it? What pressure should I expect to see?

 

[C420sailor]

Rebuild manual you used should list them. I know the ATSG manual for the 5R55E has normal line pressures and the associated diagnostics in it

Having those pressures will allow you to figure out where the pressure loss is happening

 

[Wrath]

No pressure guage handy, still waiting on separator plate gaskets to arrive, but I decided to check the servo and give the rear band a push. Servo appeared to be stuck? I gripped the tabs on the back of it and spun it to pull it out (did not come easy) wondering if I didn't sufficiently pre-lube the double-lip o-ring. Tested band with screwdriver and it rebounds fine. Reinstalled the servo and it feels much better now. I can turn it bare handed and push it up and the band can push it back. Has this ever happened to anyone?

 

[C420sailor]

That could be it

 

[Wrath]

Got it all back together, test drove it, and while it was an improvement, it still has slow shifts into gear once warmed up. Still awaiting the gaskets.

 

[Wrath]

Gaskets arrived, swapped in VB, double checked DTR alignment, cleaned corrosion off transfer case connector pins, test drove.

Goes into drive without revving, but reverse is still sloppy. I was about to drop the transmission again to pull and check the pump, but remembered I have FORScan and an ELM327 now. I see shift solenoid 1 is on even in park, is that normal? Watched EPC, 37-40 psi when idling, 27-30 psi in forward gears, but jumps up to 60psi in reverse? If I had a pump or other leak, it wouldn't be able to hit 60, right? Or are these pressures all too low? Still baffled by this transmission, and not looking forward to dropping it out again.

 

[C420sailor]

EPC numbers are all normal, as is SS1 operation. SS1 is always on, except in 4th and 5th

 

[Wrath]

Would a blocked cooler cause these symptoms?

 

[C420sailor]

No.

How are the band adjustments for the low/reverse band? Do you have engine braking in manual 1st?

 

[Wrath]

No.

How are the band adjustments for the low/reverse band?

The band adjustments for the intermediate and overdrive are good. Verified those again the other night. The low/reverse band does not have an adjustment. You got me thinking though... What's the spec for the low/reverse servo pin length? I wonder if mine is just worn down?

 

[Wrath]

Dropped the pan again and pulled out the low/rev servo. No damage that I can see. The center pin does move back and forth about a half mm though.

 

[C420sailor]

Ah that’s right. Sorry, haven’t been under there to do a band adjustment in a long time.