03 T1N TRANSMISSION HUNTING BETWEEN 2ND AND 3RD CODE 2500,2502,2503

[Jay Hughart]

Trans was in limp, no slippage detected in second gear drove it around a bit. Fixed the RR wheel speed sensor cleared all the codes. Now it shifts to second then third then drops back down to second and just keeps doing that! once it did start slipping and there was a little growl noise but then it went away. Any Ideas on this one? Thinking maybe the kickdown circuit is shorting at 476K miles..... THANKS!

 

[Cheyenne]

Thinking maybe the kickdown circuit is shorting at 476K miles.....

A good Sprinter specific scanner will be able to show you Live Data for the pedal position (2 tracks) and the operation of the kickdown switch. DO you have a Sprinter specific scanner (not just basic OBD)?

Keith.

 

[Axiom]

Inspect the Transmission Control Module underneath the drivers seat. Remove the connectors and inspect for liquid. If there's liquid in any of those wires it'll cause similar problems.

Does it stay stuck in second once it drops? If it does you may also need to drop the trans pan and clean the RPM speed sensor on the top of the conductor plate. This sounds exactly like what Shorty did to me after a month of living life like a normal van again. I replaced the conductor plate because I also had an improper dipstick receptacle, but I bet I could've just cleaned it and moved on with my day.

After you clean it, you need a Sprinter specific scanner to clear the EGS codes to get you out of limp mode.

 

[Jay Hughart]

Thanks for the replies! I have a iCarsoft MBII i980 scanner I just got. The kickdown shows "operated and doesnt change on the scanner hooked it to my other van thats ok and same thing, so thats not it. I felt of the TCM and yes there is some fluid there. can this be cleaned? brake clean? replace TCM? No it shifts to third, drops back to 2 then back to 3 over and over. Need to do more playing with the scanner and BTW I had a return pump ABS code so I whacked it with a stick and a hammer and it went away lol who knows for how long but for now no abs codes lol. Fixed the abs sensor with a stick too so to work on these an assortment of wood sticks are a must!

 

[Axiom]

TCMs rarely go bad. You just have to try and dry it out with q-tips the best you can. I wouldn't recommend spraying brake clean in there. I would use highest % rubbing alcohol you can get.

The kick-down switch is not operating because you're in limp mode, and the liquid in the connector would be why.

You probably need to put a new 13-pin plug on it. You can do this without dropping the valve body/pan.

@ 12:31 in this video I pull it out and put a new one in. Make sure you push it all the way in, we have a wood stick for that

After this, with your iCarsoft MBII: Select Sprinter, then "901, 902, 903, 904, 905", then diesel, then "EGS (Transmission Control)". Read & take a picture of the codes first. Then clear them with the scanner. See what comes back if any.


What's happening is the o-ring or the plug or both are bad at the transmission, it's recommended you change the plug with every transmission service for this reason. When it goes bad, transmission fluid wicks up the wiring harness into the TCM at the cab. It sounds scary, but it's common and we've had to fix a few times. Luckily the plugs are cheap and usually come with the service kit.

 

[Jay Hughart]

Ok I ordered a few of those Connectors. Pulled the TCM and it was a tad grimy but no wetness really on the pins just a dab on the one connector, so I put it in my van, drove fine so I cleaned it and the connectors and reinstalled it. Doubtfull I fixed anything but will try to drive it tomorrow and see. Dont think there was enough fluid there to cause any problem. onna try to check some readouts on the scanner then Drop the V/B

 

[Midwestdrifter]

Sometimes only a little fluid shows up at the connector. I would shake the TCM to make sure there isn't any pooled inside.

 

[Jay Hughart]

I put it in my other van and it shifted fine so.... NOT the TCM. put it back in today and same thing first...... second..... third..second..third..second. Shifts perfect up to 3 then drops to 2 back to 3 and just keeps doing that. Even on a decel. Tried to play with the slap shift and could not get 4th. When I pulled back in I think it was "stuck" reading 4 on the dash but I think it was in 2 actually.... The saga continues!

 

[Midwestdrifter]

So, with a scanner on tcm live data, what does the actual and requested gear show?

 

[Axiom]

Your next probable cause could be a gunked up RPM speed sensor. That’s the one on the conductor plate and can be cleaned. Have you performed a full service on it yet?

 

[Jay Hughart]

Ok, No but I think I figured it out. the 2-3 shift solenoid is "only applied during the shift" So if I understand it right it applies shifts from second to third then power is cut. power it again and it shifts from 3-2 and then power is shut off to it. I have surmised (correctly?) that the solenoid is mechanically failed in the stuck open valve position causing it to constantly shift between 2 and 3. Maybe wrong but its not legal so in lue of driving it anymore Im going to drop the pan clean the conductor plate and replace the 2/3 solenoid. Thanks everyone for there input will keep ya posted!