Shadetree Mechanic Tranny Rebuild (Part 2)

[Cruiser Jimmy]

Update on the Failure

So I took the cut open torque converter to a local guy that rebuilds them and understands what he's looking at. There are only a hand full of things that can go wrong with a TC, the one-way clutch that's for the stator, bearings not having sufficient lubrication, or the lock up that has lost it's clutch material over time or miles.

The mechanic looked at the lock up and in not so many words, said that's your problem. The lock up plate should have about 30 to 70 thousands inch of clutch material depending on the manufacturer. My lock up plate was down to the bear metal in spots with very little material and dark brown in color. New lock up plate material can very in color, from red to brown and anything in between.

Some education about the lock up that I had to ask an expert:
The lock up is triggered by vehicle speed and hydraulic pressure from a signal relay in the valve body or a solenoid for the A442F trannys. On the cruisers it's around 47 to 55 mph. Before the lock up engages, hydraulic fluid (I'll call it oil from now on) is sent through the overdrive planetary gear, (that's the shaft that comes out of the oil pump.) The oil then moves out to the torque converter from the impeller then to the turbine which then starts to couple and transmit torque to the tranny.

Once vehicle speed reaches 47~55 mph the transmission stops sending oil through the planetary gear and something like centrifical force moves the lockup plate up against the front cover.
At this point the oil is still flowing around the lockup but not that much, the oil makes it's way out to the oil cooler then back to the tranny.

I'll continue to update, but for now it appears that the TC lockup was the main problem. My TC has over 250K miles on it and should have been replaced when I did the transmission rebuild.

 

[girraffe]

Revving this old thread here. What did you think of the aftermarket clutch packs? Would you go with oem now that the tranny has failed? Which would you or your transmission friends recommend and why?

 

[Cruiser Jimmy]

The aftermarket clutches were great. I drove on them for 8 months without any issues whatsoever. Raybestos if I remember correctly. I did not have any problems when I was under 45 mpg. The problem happened because I did not get the TC referb'ed during the same time as the rebuild and when I got above 45 mph the TC lockup engaged. The tranny is still seating in the garage and I have not touched it. Until I tear into the tranny my theory is it over heated as a result of the TC.

 

[Wheelingnoob]

Thanks for both of the threads! I am planing on rebuilding a A440F for a project I'm working on. I too will start with the master rebuild kit (Rock Auto has the same one for $220). The Torque converter is headed to the a shop in AZ for a rebuild with carbon fibre HD lock up clutch and stalled down to 1500-1600 RPM (diesel swap).

Thanks for all the work you did with documentation on your rebuild.



Let us know if you ever take it apart and find if your hunch was correct.

 

[Cruiser Jimmy]

Will do.

 

[quabity control]

TC thoughts

Sorry for the gratuitous hijack (but on a very related note to this thread), but this thread hits pretty close to home for me. I have an A343 that is pretty erratic on the lock-up at freeway speeds. I've verified that it's not a signal problem from the computer, but on the freeway I can tell it's flipping pretty quickly from locked to unlocked, sometimes once every few seconds . I've got about 220k on the clock and everything is shifting just fine, except for the TC issue.

FSM seems to indicate it's either a TC wear issue or a solenoid issue in the VB. This thread is emboldening me to get a cheap core and rebuild one... however, based on the comments about how VB's can be pretty finicky and since it would be wise to get a new TC in ANY case and since it's so relatively simple to just pop the new/rebuilt TC in there, I'm thinking of just doing that first and see what I get.

Jimmy, just wondering in your conversations you had with a few transmission specialists if they said that lock-up issues are generally due to worn TC clutch or other? And thank you for such an amazing write-up.

MM

 

[Cruiser Jimmy]

I don't have your years FSM in front of me and I'm not intimately familiar with the 343 so the course of action on problem solving would be my method based on what I have come to understand about trannys.

Before you expense a VB I would start with the solenoid being replaced first. They pretty easy to get to once the pan is off, IIRC.
The TC for the 80's are all the same on the inside, just differences with mounting on the outside between all the years. The Lockup activates with only hydraulic pressure. The method by which it gets the signal to do that is mechanical and electric between the years. You may have an all clear from the computer's codes but with the solenoid hopping in and out like you claim leads me to believe that it's a $40 solenoid issue.
The governor inside in the back of the tranny plays a part in this but I don't think it's an issue. You would have other issue if it was.

Replacing the TC is your call. If you have not towed excessively over the stated rating, you have good cooling to the tranny radiator and your temp light had not come on then your TC should be still in good shape.

Hope you find your issue at the lowest cost.
Jim

 

[CJF]

on the freeway I can tell it's flipping pretty quickly from locked to unlocked, sometimes once every few seconds .

I may have already mentioned this in one of your threads, but:

We had one guy here with similar symptoms, and the problem was as simple as a broken return spring on the brake pedal, so the computer kept thinking he was hitting the brakes and therefore kept unlocking the TC.

 

[quabity control]

Thanks for the reply Jimmy (I thought you might be subscribed). I'll drop the pan and replace that solenoid and see if that does it. Then next course would probably be the TC, I guess followed by out and out rebuild. Such a great guide, I know it's a drag to stop and take pictures while you're trying to get stuff done, but SO helpful for those who follow.

MM

 

[quabity control]

I may have already mentioned this in one of your threads, but:

We had one guy here with similar symptoms, and the problem was as simple as a broken return spring on the brake pedal, so the computer kept thinking he was hitting the brakes and therefore kept unlocking the TC.

CJF - You had the same reply in another thread and I did check, no bones. Return spring is good. Would have been nice, though.

 

[Cruiser Jimmy]

I may have already mentioned this in one of your threads, but:

We had one guy here with similar symptoms, and the problem was as simple as a broken return spring on the brake pedal, so the computer kept thinking he was hitting the brakes and therefore kept unlocking the TC.

Thanks for the info Curtis. I'll keep that in mind when I have another 80.

 

[landcruiserhdj80]

Update on the Failure

So I took the cut open torque converter to a local guy that rebuilds them and understands what he's looking at. There are only a hand full of things that can go wrong with a TC, the one-way clutch that's for the stator, bearings not having sufficient lubrication, or the lock up that has lost it's clutch material over time or miles.

The mechanic looked at the lock up and in not so many words, said that's your problem. The lock up plate should have about 30 to 70 thousands inch of clutch material depending on the manufacturer. My lock up plate was down to the bear metal in spots with very little material and dark brown in color. New lock up plate material can very in color, from red to brown and anything in between.

Some education about the lock up that I had to ask an expert:
The lock up is triggered by vehicle speed and hydraulic pressure from a signal relay in the valve body or a solenoid for the A442F trannys. On the cruisers it's around 47 to 55 mph. Before the lock up engages, hydraulic fluid (I'll call it oil from now on) is sent through the overdrive planetary gear, (that's the shaft that comes out of the oil pump.) The oil then moves out to the torque converter from the impeller then to the turbine which then starts to couple and transmit torque to the tranny.

Once vehicle speed reaches 47~55 mph the transmission stops sending oil through the planetary gear and something like centrifical force moves the lockup plate up against the front cover.
At this point the oil is still flowing around the lockup but not that much, the oil makes it's way out to the oil cooler then back to the tranny.

I'll continue to update, but for now it appears that the TC lockup was the main problem. My TC has over 250K miles on it and should have been replaced when I did the transmission rebuild.

Hi i'm looking at youre rebuild. well done.
But maybe was it in the first place the Valve body the problem, that you burn the C2 clutche...... and with rebuilding it and not change or testing the valve body pressure valve for the TC. And that could be the problem the friction from the Lock up plate is gone.