Jump to content

I think I broke my transmission!


rhelm1953

Recommended Posts

When I purchased my 1950 Plymouth three years ago it had already been converted to a 3-speed overdrive and after adding the correct relay and cleaning up some wiring the transmission and overdrive have been working just as designed by mother Mopar.

A couple months ago the master cylinder failed so I took the opportunity to upgrade to front disc brakes and dual master with remote fill.  While I had the car in the shop I also replaced the oil pan gasket and planned to replace the parking brake drum.

The brake upgrade went without a hitch, as did the gasket replacement.  After I removed the old hub from the back of the transmission I discovered the replacement parking brake drum I had was not compatible with the overdrive so I put the original hub back in place, reconnected the drive shaft and lowered the car to the ground.  When I put the car in reverse to back out of the garage and let out the clutch the engine stalled, I tried a second time and the engine stalled again, I put it in first and eased ahead, no problem, put in reverse, let out the clutch the engine stalls.  Bottom line the transmission works in the 3 forward gears when I have the rear axle up on jackstands, but is locked when I place it in reverse and will stall the engine.

Procedure to remove/replace rear hub on transmission:

Car up on jackstands

Remove driveshaft

disengage overdrive and loosen retaining nut (nut was tight but not frozen)

remove hub

replace hub

tighten retaining nut and torque to specification

reinstall driveshaft and lower car to the ground

re-engage overdrive

Attempt to back up and transmission locked in reverse

 

Troubleshooting to date

Shift lever moves smoothly through all positions

I can "feel" 1st and reverse engage when I shift gears

examine shift linkage and review adjustments from service manual (everything checks)

disconnect shift linkage and manually move shift levers to place transmission in reverse (still locked)

Test reverse with overdrive engaged and disengaged (no change reverse still locked in both cases)

With the transmission in reverse and the clutch depressed I can smoothly turn the driveshaft in both directions,  but when the engine drives the transmission it is locked

 

One possible cause?

When I engaged and disengaged the overdrive while trouble shooting the overdrive cable slipped in the clamp, this raised the possibility in my mind that when I re-engaged the overdrive after replacing the rear hub it might not have been fully engaged.  If that were the case could that damage the overdrive and cause the problem I am having.  In troubleshooting I have disconnected the cable and manually moved the overdrive lever to full stop in both directions and tested reverse (it remains locked)

 

I really don't want to pull the transmission but I have convinced myself this is not a simple shift linkage adjustment problem but that something has broken in the transmission.  I am at a loss as to what that could be and how it could happen with the work that was done.

 

I appreciate you feedback and thoughts.

Link to comment
Share on other sites

Turn off the OD! Push handle to disengage if not already done.

 

Trans will Not work in reverse if the OD is engaged!

 

It is supposed to turn off the OD when in reverse is selected manually in the trans but something has happened somewhere during your changes?

 

Hope there is some help here.

 

DJ

  • Like 1
Link to comment
Share on other sites

Yes I am now thinking the problem is in the overdrive and not the transmission itself.  I just don't understand how anything I did could have caused the problems I am having.  I am mentally preparing myself to pull the transmission this weekend.  :wacko:

Link to comment
Share on other sites

I'm back on the road and did not have to pull the transmission!.  The problem was the overdrive solenoid was engaging when I turn on the ignition, with the overdrive engaged reverse was locked up.

The reason why the solenoid was engaged is a bit of a puzzle.  I wanted to add an indictor light to come on when the governor switch closes to the car easier for my wifr to drive so she would know when to let off the gas to switch to overdrive.  I got a 6V LED and wired it in parallel with the overdrive relay.  One wire connected to the horn relay that's hot when the ignition is on and one wire connected to the ground circuit through the governor switch.  For some reason when wired like this the overdrive would be disengaged when the car first started but one the solenoid was energized it would not release when the governor switch opened.  Even more strange when I disconnected the LED lead from the horn relay so there was no power to the LED the problem continued, I had to disconnect both leads of the LED for the overdrive to work correctly.

For now I have given up on the indicator light and the car is working perfectly.  I will think about this some more.

Link to comment
Share on other sites

Would it be possible to just mount a brake light switch, the type that is used on hanging pedals and has a button thats pushed or even a door light switch and just mount it so that the button is pushed by the O/D lever and you just have a completely separate power circuit to this switch and back to the indicator light........one thing I've noticed is that there seems to be a range of problems encountered by those using the original style Mopar/Borg Warner electric overdrives and that coupled with the cost that they go for now was what made me decide to get a T5 gearbox with its purely mechanical overdrive selection.........but that was just me, of course there are other factors that come into play also but as I ended up selling the car & gearbox etc its a moot point anyway..........lol...........just thought I'd throw my Oz 2 cents in..............I'll go back in my corner now........lol...............Andy Douglas   

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Terms of Use