M1009 transmission not working properly

[gafuller01]

I have searched through the posts, but have not found anything helpful so far. Maybe someone can help me.
I have a 86 M1009. For a little while now, the truck has had trouble climbing over small (1-2 inch) curbs or obstacles without a running start. The engine revs up fine, but something seems to be slipping. Yesterday, the truck stopped shifting into 3rd gear, and reverse has become very sluggish. I checked the transmission fluid, it is full and looks brand new. The truck will pull just fine in 4 low. I crawled under the truck to look around and found a pretty significant leak from the transfer case tail cone gasket and the rear seal. I don't think the t-case being low would cause these symptoms though.
Any thoughts?

 

[ryan77]

First thing is to check the transfer case fluid level!!

 

[cliffyp]

No 3rd up shift could be low pressure, governor problems, valve body problems or clutch problems.

I'd start with by checking your pressure. If its low, that could also lead to a sluggish reverse.

There is a pressure port on the driver's side of the transmission. Off the top of my head, I think it's 1/4 in fitting. Unscrew it and you can check size. Put a hose and gauge in there.

Here are the pressures you should be getting. All of the following are with breaks applied and rpm @ 1,000

Neutral: 55-70 psi
Drive: 60-90 psi
Drive "2": 135-160 psi
Reverse: 95-150 psi

Drive @ idle: 60-85 psi

Check your pressure and go from there

 

[cliffyp]

And of course make sure your fluid levels are correct before doing anything!

 

[AZDeuce]

My M1009, wouldn't shift to third, a guy showed me the fix, at least in my case. On the passenger side of the transmission toward the rear is a plate with 4 bolts carefully remove that and make sure nothing flys out into space under spring pressure, but if I remember right, that is not an issue, once that plate is off I believe there is a long valve I can't remember if it is attached to the plate or seperate (sorry I did this several months ago, and don't remember all the details.)

I had to remove the valve from it's housing as it was sticking, I think I had to punch out a pin, and plastic gear to remove it. I cleaned it up in some solvent there was some debri in there, gave it a quick polish with some crocus-cloth, cleaned and reassembled it. The truck has been running fine ever since.

Hope this helps

 

[cliffyp]

That's the access plate to the governor assembly. A faulty governor will affect shifting, and could be your 3rd gear problem, but wouldn't have anything to do with slipping or sluggish gears at take off.

Of course you may have more than one issue going on in your trans.

 

[ryan77]

I agree with checking the governer! Check make sure the gear isnt stripped and everything moves free! From what ur describing sounds like its time to rebuild the trans! Turbo 400 are cheap and easy to rebuild!

 

[gafuller01]

Thanks for all the suggestions. I won't have time to check most of these out until the weekend. I have checked the fluid levels and they are all okay. I have a feeling I'm heading toward a tranny rebuild, but I will check everything else first.

 

[gafuller01]

Checked everything this out this weekend, looks like the tranny rebuild is in order. I pulled the tranny today, tore it down, and ordered parts. All clutches were burned, drums look okay. Pressure was not very good, so I will rebuild the pump while I'm in there. I also decided that since the cucv will be deadline for a while I might as well have the injection pump rebuilt, 27 years is long enough. Removed the IP and sent it off today. Now I'm just waiting on UPS and Fedex to bring my goodies.

 

[gafuller01]

Rebuilt transmission this weekend. While I was in there I also found that the accumulator piston(plastic type) was broken, and the vacuum modulator was not working right. I took the transfer case apart and resealed it while it was out. Put everything back together today. Just waiting for my Injection pump to come back from the rebuild shop so I can test the vehicle.

 

[5moker]

I too am struggeling with mine (m1009). No 2nd or 3rd upshifts. Solid in first and reverse, tried manually shifting with no success. Fluid is level good and clean. Vaccum seems pretty week off the pump. Suction barely holds the tube to my finger. Hmmm

 

[ryan77]

Change your vacuum pump!

 

[5moker]

That is what I was thinking but.... First diesel/first mv. Just dropped a hummer motor in it. Farm fresh with blown motor. Know chevys. Know gas motors just going through a few things for the first time! Enjoying it!!!

 

[5moker]

 

[doghead]

Hummer motors do not have vacuum pumps.

 

[5moker]

So the vaccum pump should be creating alot of vaccum? would that prevent even a 2nd gear start? Or manual upshift?

 

[cliffyp]

I too am struggeling with mine (m1009). No 2nd or 3rd upshifts. Solid in first and reverse, tried manually shifting with no success. Fluid is level good and clean. Vaccum seems pretty week off the pump. Suction barely holds the tube to my finger. Hmmm

Check your governor, a faulty governor will prevent any upshifts. There is an access plate towards the rear of the trans, passenger side if I recall correctly. The plastic teeth get worn. Very quick and easy fix.

 

[5moker]

Haha yep no vaccum pump on a hummer motor!!! That is why I used my old one and IP! Since I didn't have the ecm or 4l80e (or whichever the hummer runs). Oh and the oil pan! Any helpful advice would be greatly appreciated! Been at the truck non-stop for 2 weeks. Replacing all hoses, cleaning electrical ect. Patience is running thin. Just started paint today! I just got the motor finished last night. Seems pretty strong. I would like the other gears though so I can get a real feel...

 

[5moker]

Not my first rodeo work on old chevy trucks Just got to get used to the 24 volt system and diesel. I run diesiels in a charter boat but they are old 4-53 detriots. No glow plugs. Just forward and reverse trans. Nothing fancy. very old school.

 

[5moker]

Thanks cliffy. If the vaccun pump is a problem wouldn't you still be able to manual shift second? I may be dealing with multiple issues here. I am going to wind up with a 30 y/o new truck if I don't slow down!