View Full Version : '55 President transmission

01-27-2007, 05:07 PM
Here is the paste from the original paste where I first posted the problem:

The engine would not start with the lever in Neutral, but I had to go to Park (I assume the neutral safety switch maybe?) But mechanically the tranny was not in Park because as we ran the engine the drive shaft (which is disconnected from the rear for rework) started bouncing around and hitting the floorboard. We went through all the gears by hand under the car and could NOT keep the driveshaft from turning. Broken parking pawl or something else?

As for the tranny, I assume you have the OEM tranny, a Borg Warner DG250. The driveshaft should NOT turn AT ALL in park or neutral! (Period). No the fault does not lie with the parking pawl, even if it works, which it sounds like it didn't, with an engaged gear, the engine will turn the tranny with enough force to break the parking pawl -only a complete car, with tires and brakes applied could stop a tranny with engaged gears. If your tranny was in park, then either your parking pawl was already broken (many are sheared off from mis-use over the years) OR it became broken when you started the car and the tranny was engaged OR the pawl is not adjusted right and didn't engage the main shaft, i.e. there is a bolt on the inside, seen by dropping the oil pan, that is used to adjust the pawl's engagement. Anyway, moving on since the pawl is not the problem you have...

Something is wrong if its turning as you say. Was the tranny rebuilt properly, i.e. by someone competent in the older Tranny designs of the 50's era, especially the DG series? If rebuilt, did it sit for a long time, say for a few years? Here's a quick list of the DG250 tranny problems that could cause your issue: 1) Too tight brake bands, if they are not adjusted right they will grab the main shaft drum and engage the forward or reverse gears depending on the band that is too tight -conversly don't make them too loose or else the gears won't engage. This is probably the easiest item to check, just back off the adjusting bolts to loosen up the bands...don't go too far or the strut that engages the adjusting bolt to the band may come loose and then you'll have to disassemble the tranny some to put it back. To play it safe you could tighted the adjusting bolts until they stop, then back them off about 4 turns (IIRC, I'll see if I can get more accurate when I crawl under and work on my tranny in the next few days). There are three bands, low, forward, and reverse, each with an adjusting bolt..see the shop manual for specific instructions for help on adjusting. 2) Direct drive engagement: the clutch in the torque converter is locked up, either due to Torque converter failure or the valve body is delivering the clutch pressure when it shouldn't. 3) Hydraulic pressure system malfunction, i.e. the Valve body or governor valve is malfunctioning: For the brake bands to engage gears and the direct drive engagnement, they are all controlled by pressure from the pumps and this pressure is controlled and routed by the valve body and the governor valve. The valve body has numerous valves and many passages that can be blocked. If any of the valves fail (blocked, stuck), especially in an open position, then it COULD engage a brake band and put the tranny into gear. The governor valve controls shifting while moving and while unlikely to fail and create your problem, there exists the possibility that it could be broken or is stuck and thus allowing pressure to engage the direct drive. Item 2 and 3 are more difficult to diagnose, you'd need to run pressure checks as per the shop manual using the proper equipment, and that might be hard to do while trying to take car of an engine that is being broken in and needs all sorts of attention to get it running good. Let's pray you have something simple like brake bands that are too tight.

Disconnect the shift linkage at the transmission and push the lever on the side of the transmission all the way forward and see if that will lock the driveshaft.

To reiterate, the pawl is not your issue, although it may not

01-28-2007, 12:44 AM
Congrats on getting the car to move, at least a few feet out and back into the garage. So it sounds like you figured out what was happening with the tranny, that is great.
I just finished fixing my DG250, it needed a new piece internally. I got my parts Weds, put it together Thursday and then installed it this morning. My test drive went great.

E. West
"The Speedster Kid"
Sunny Northern California
Where the roads don't freeze over and the heat doesn't kill you.
And an open road is yours to have -only during non-commute rush hours 9am-4pm and 7pm to 7am (Ha, ha, ha)

01-28-2007, 09:03 AM
Alright! Two success stories. Hope to get to the rear brakes soon and then I can do a test drive.

'55 Commander
'55 President