Stuck in First Gear

[Red Rocket]

Hello,



I've got an 06 with the 48RE. This morning I started it up to go to work, and it wouldn't shift out of first gear. Eventually I decided that if I rev it to 2850 or so, then aggressively let off the throttle, it would shift to 2nd, then normal from there, but first gear does the same thing every time. There are no codes related to the transmission. It's been a couple years since the fluid was changed, so that probably needs to be done anyway. Having said that, what could cause this sort of behavior?



Thanks



Nick

 

[cerberusiam]

Usually that is the output speed sensor causing a very late shift, its on the driver side of the OD housing. If you have not changed the transducer and gov solenoid it may also contribute to the problem. The speed sensor is external and easier to change as a start.

 

[Red Rocket]

After driving a bit further it appears that 2nd is not engaging at all... . temp reads 30 all warmed up.

 

[cerberusiam]

That would cause it also. Can you get manual 2nd or is it in free wheel mode when you do that?

 

[Red Rocket]

Scratch that, if I select 2nd manually it works, and locks up properly.

Temperature readings are now at 110, but the readings are very erratic, varying 20-30 degrees by the second, highest temp I saw was 125, truck has driven 50 miles today.

 

[cerberusiam]

How are you reading trans temp?

Probably time for a service and gov transdcuer\temp and solenoid change out anyway. Might try the output shaft speed sensor first, they are only $20 or so.

 

[Red Rocket]

I'm reading the trans temp on my Edge Juice Attitude. I'm gonna pick up an output speed sensor now. I'll report back on that in an hour or so.

 

[cerberusiam]

While you are at it, check the trans control harness plug for fluid contamination. With the flaky temp readings and the other problem it could be fluid in the plug causing all of them.

 

[Red Rocket]

Well we've cleaned up all the connections and replaced the speed sensor. No change. I can also confirm that I can only select 2nd gear when the transmission is good and warmed up.

I guess it's time to swap out that solenoid and sensor.

 

[Red Rocket]

Is there any place to buy a Borg Warner 50185 locally, the heavy duty solenoid I'm reading about? Where can I get one?

 

[cerberusiam]

Did the cleaning help your trans temp fluctuations?

Any transmission warehouse should have what you need. Probelm is it may be the same crappy OE stuff that is problematic. Dealer has them also but they want 3 times what you can get them for oline.

 

[Red Rocket]

This issue is fixed, the new solenoid and transducer/sensor fixed the problem. My temperature readings are now normal, and truck shifts perfectly.

I got the parts from a local transmission shop, he had no idea about the upgraded solenoid, but when I mentioned Borg Warner 50185, he knew exactly what I wanted and had no problem selling it to me.

I've only driven a small distance, but it seems like the hunting from 1-2 is gone!!! That would be sweet, it's done that occasionally for 120,000 miles. Thanks for the help.

 

[cerberusiam]

Yeah, and its hard telling which part was the real culprit. My bet was on the transdcuer with its flaky readings. Glad you got it fixed.

 

[S.Morris]

Guy that does our auto tran work will not use the Borg Warner unit... ... ... he did when it first came out, and told me that he had early failure/erratic operation of every transmission he used it in. Borg Warner tech line basically said we'll get back to you, but never did. It is possible that they have rectified this problem. He see's few failures of the OEM solenoid until quite high mileage in properly maintained units