1009 transmission trouble - AGAIN

[msoumas]

I had the TH400 in my M1009 rebuilt last year, and just now seem to be having renewed troubles. My younger brother took it for a "spin" and later admitted that he tried to make the tires spin with some gas + brake in the rain. Now, whenever I try to get to speed, it revs waaaay higher than usual before slamming into gear. I was away from home and it was raining, so I wasn't able to check too much. I did check the vacuum lines in the engine compartment running from the IP, both looked fine. Also checked transmission fluid, looked good and no burnt smell. Anything else I should be looking for?

 

[jwaller]

looks like your brother owes you a transmission.

 

[msoumas]

looks like your brother owes you a transmission.

...Seriously?

 

[12vctd]

I learned many years ago about th400's and power breaking, it causes alot of stress to the low roller clutch and can wipe out a sprag or drum very quickly.

But if the trans is shifting just at higher rpms I would still suspect the vacum modulator, or lines.

Does the transmission shift thru all foward gears? Is reverse working properly?

Is the problem occuring between all shifts 1-2 2-3 or just the 2-3 shift?

 

[msoumas]

I learned many years ago about th400's and power breaking, it causes alot of stress to the low roller clutch and can wipe out a sprag or drum very quickly.

But if the trans is shifting just at higher rpms I would still suspect the vacum modulator, or lines.

Does the transmission shift thru all foward gears? Is reverse working properly?

Is the problem occuring between all shifts 1-2 2-3 or just the 2-3 shift?

Problem is between all shifts. It runs fine at lower speeds, reverse works fine too.

 

[raiburn]

If when you had it rebuilt, they installed a new vaccum modulator, you can pull off the vaccum hose, and stick a very small flat blade screwdriver, and turn it counter clockwise to lower the shift points, clockwise to raise the shift points. When my th400 was gone through, it had way too high shift points, so i adjusted the vaccum modulator, and now its ok. If yours has been fine since rebuild, this might not matter, but you can try to see if it lowers your shift points. I turned mine a full turn for each try. eventually took about three turns!! This is the big flaw in this tranny imo. You said you checked the vaccum hoses, but you should check them again, that would make perfect sense. I didnt know mine were dry rotted until i took one off because it was in the way of another repair, and it had a hole in it. Quadruple check it. Joe.

 

[12vctd]

if it shifts fine at lower speeds, I will go out on a limb and assume your either experiencing vacum line issue, or a vacum modulator issue, or a fragged governor. So lets go diagnose this simplest to hardest. First triple check or run new vacum lines at a min put them on a vac gauge with one end capped and pull vac on them those lines are very hard to visually see any small leaks and a small leak can be just as mucha problem as a larger one. Once you know the lines are 100% just as raiburn suggested, clockwise will increase the shift counterclock wise will lower the rpm. if this has no affect then let us know and I will, walk you thru testing your Govenor. its easy to replace and they are comon to get stuck or stick some. You can also pull the pan and inspect the fluid to see if any hard parts have broken, but I think you will be fine.

 

[msoumas]

Lucked out, it was nothing. Had it not been raining, I would have gone underneath right away and seen that the line to the vacuum modulator had blown off. Crisis averted, I suppose.