HELP NEEDED! one step forward, two steps back...

[Heinz55]

Engine rebuild: Done
Wiring: Done
Seats: Done
Front brakes (and brake fluid spill on front concrete walkway cleaned up): Done

Now the main issue. Truck will not stay parked in park. When I stop, place in park, and turn off truck, park does not hold truck in place. I seems as if the gears are not holding it.

I know almost nothing about transmissions. I have a Th400, any ideas why this is happening?: Low fluid? Rebuild needed? Virgin needed to be sacrificed?

I just want to drive this truck (which technically I can, all trips need to start and end at home so I can chock it in place).

Any advice or shoulders to cry on appreciated

[OrrieG]

someone with better knowledge of the inner workings can add detail but all automatics use a mechanical locking device for park. check the linkage and arm on the trans without the linkage xonnected. if it locks w/o linkage then its an adjustment. if not i susprct you need to get inside the trans.
Posted via Mobile Device

[Tchia65]

Automatics do use a mechanical linkage, it is literally a stamped piece of steel that fits into serrated cut outs on the drive drum. It's called a parking pawl. If the tranny is new, the internal lever might not be installed. Either way disconnect the linkage. rotate the gear selector on the tranny and check for all the detents. first, second, drive, neutral, reverse, and if you get a "click" for park check your wheels. If they are locked it's just an adjustment issue. Do you have rod linkage or a cable from your gear selector in the truck?

[OrrieG]

I found this in a jeep forum. looks like you can access by "just" removing the trans pan.

"Has the tranny been worked on lately? When I had my th400 rebuilt, the shop put the park linkage plate in backwards and it wouldn't stay in park on hills. You need to drain the trans, remove pan and filter. Find the metal cover over the parking gear plunger, it has two bolts through it and can be bolted in either way, common mistake to put it in backward.
Look for a th400 rebuild book at B&N or Borders and look up parking linkage and it discusses this in detail"

I googled th400 parking pawl and it was one of the first hits.

[entourageguy]

And make sure you do this with the wheels properly chocked and the parking brake on. Nothing worse than being under a truck working on the trans and popping it out of park. .... ouch or worse

[kaycee]

It's easy as pie do like they say but before you pull the pan make sure your linkage is adjusted right you could be running short of linkage.This making it not catch in the park pos.This was happening in my 69 the rod was not long enough then I added about 2" and it catches the parking pawl like it should.Taking the pan off is no big deal especially to look at the parking pawl once you have the pan down you can see what you need to if the problem is in the pan.

[Wheelie]

Parking pawl not engaging due to either mis adjusted shifter cable or broken/missing.

[mr48chev]

Originally Posted by Wheelie

Parking pawl not engaging due to either mis adjusted shifter cable or broken/missing.

The first thing is to figure out if you are actually getting it in park. Are all the other gears correct as far as the indicator goes? If it's in drive and the indicator needle is on neutral you won't get the shift lever moved enough to get the trans in park properly. If it is out the other way you won't be able to get it into low gear manually.

[Heinz55]

First, a big thanks to all those who have given advice.

First day off in a while is tomorrow (been working those 16 hour days and it was killing me, I know we have all been there). Plan is to start with the linkage. This truck looked good to me when I bought it, but with the knowledge I have now after two years with this forum the list of things to do almost seems endless. The current linkage is "functional" at best, but after weighing all the advice given it seems to be the most likeliest and easiest to check.

Truck currently has no parking brake another thing to fix), but I am always sure to chock it if I need to work on it. before going under the body, I always shake the heck out of what ever choke/jack/jackstand/6x6 system I have to make sure it does not kill me. I would never hear the end of it from the wife if it killed me while working on it.

Current plan of attack is to take off linkage, manually engage the tranny into park, and see if that "parks" it. If that works, then I guess I need to adjust or replace the linkage. The one I have now is a homemade setup, would feel better with something tighter and with more "ease of mind"

I'll let ya'll know how it turns out

[Heinz55]

So, it was just the linkage. The final click into park was not happening, I guess the linkage bar was finally too bent to allow full range of motion. I am going to replace it with a cable, any suggestions on where to get on with all the brackets I need as well?

[kaycee]

Why dont you cut it in the middle somewhere and put a filler piece in and weld it back?

[OrrieG]

two comments. if you used linkage from a car try a rod from a pickup, they are a little longer. that is what I had to do on my Chevelle. If you go to cable look at my build thread, I assembled pieces that work the same at half the cost of kits from suppliers.
Posted via Mobile Device