1985 CUCV M1009 Normal Shifting?

I have a M1009 that I just started driving on the road this week. I was wondering if the shifting was a little late. It shifts from first to second between 25 and 30 MPH. It shifts from second to third between 50 and 55 MPH. Are these shifting speed ranges normal?

Normal if your vacuum lines are bad!

Check/replace the small rubber lines that run from the top front of your engine and down the passenger side. They commonly look like sponges, and seal just as well. I had exactly that issue with my 1009, cost me a staggering $2 to fix it with new lines.

If that doesn't cure it, there are a bunch more posts in the CUCV section covering other shifting issues in detail.

Cheers

I have hard shifting and long gear changes on the another M1009 I started Monday. The shifting on my M1008s are all smooth and (I would say) normally spaced for a diesel.

I'm thinking there is too much ATF in it (stick shows too much) and perhaps a clogged filter. I have driven on the hiway and residential streets, so it was warm. I'll drain and replace fluid and filter this weekend. You should too.

But now my 1031 rattles sometimes when it is upshifting to third (sounds like loose inspection cover or (god forbid) my flexplate or converter have loose bolts.

So my last thought is - it's a disease spreading from the bone yard into my active fleet.

I'll need to start a tete-thon, cuz "It's for the Children"!

Hello. According to the Operator's Manual TM 9-2320-289-10, page 1-14 to 1-16 using the stock size tires at the proper PSI (this may be different for the rare few M1028A3 and M1031 that supposidly have Dana70 with 4.88:1 gears)
ALL CUCV series "Maximum Speed" in 2 Wheel Drive; 1st. 25MPH, 2nd. 35 MPH, 3rd. 55 MPH, Reverse 9 MPH.
The maximun speeds in "4 LOW" are slightly higher for the M1009; respectively, 14 MPH, 23 MPH, 35 MPH, reverse 9 MPH. All others; 10 MPH, 16 MPH, 25 MPH, 9 MPH
The maximun speeds in "4 High" are the same for 'ALL", repectively; 25 MPH, 35 MPH, 55 MPH, reverse 9 MPH.
This are the military recomended speeds indifferent of the transfer case (NP208 or NP205) different 4 LOW ratios.
Of the seat of my pants I would say my M1008 shifts points during easey acceleration with OEM or 36" tires are; 1st. - 2nd. @ 10-15 MPH , 2nd. to 3rd. @ 25-35 MPH. Durring hard aceleration a little harder shifting at somewhat higher speed, when I installed the 36" tires a transmission shop adjusted the shift points, this adjustsments have being cover elsewhere in this site.

I agree with M813rc, check the vacuum lines. It'll make the Th400 shift late just like you described. The th400 will up shift even when pulled down to 1st on the column once the line pressure gets high enough. That's what your's is doing, shifting off of line pressure instead of vacuum signal.

Im in the same boat but first doesn't like to shift till around40-45, and second is around 55+, this weeknd i will likely be replacing the vacuum lines and hopefully that will take care of it.

If you want to try something different-- run the vacuum line from behind the engine directly to the vacuum fitting on the trans --get some good long vacuum line--the trans will shift at 10 mph and 25MPH --you can hardly feel the shift-- the engine rpm feels good at the shift points--bypass everything--if you do not like it you can hook it back the old way --I have done it on 4 m1009s--also make a cover that only seals the top of the air filter and leave off the orginal top of the air cleaner housing--The extra air thats gets in adds alot of torque to the engine--its suprising--

Ok Ill look into that that might save me some time, how does ur mod feel when you are 4 wheeling? Does it shift to soon when in 4lo?

Also do you have a pic of?

also make a cover that only seals the top of the air filter and leave off the orginal top of the air cleaner housing

Click to expand...

Feels good---

look in the back of the engine--the vacuum line is right there--look at the passengers side of the trans--the line is there--easy stuff--I do not have any pictures--when you change the air cleaner around the engine has a whole different sound on acceleration and sounds great--you can hear all the extra air being sucked in--

I replaced the vacuum pump after I didn't know you could rebuilt it, But that fixed mine. Also there are adjustments in the transmission if you can find someone that knows about these.

What did you use to create a new top for the air filter?? Do you go through air filters faster this way?

I used a piece of sheet metal--put the air filter on top of the metal and trace the diameter and then cut the metal to size----drill two holes to line up with the hold down nuts--my brother used thin plywood and that worked--you suck in much more air so the filter will get dirty faster--blow the filter out with compressed air to clean it

Thanks!

So that's why my M1009 is shifting so hard! I was hoping there wasn't a bigger problem.

I thought it might be normal for mine since it has a 6.5L in it.

Thanks for the info!

I’m posting this message to thank everyone on this thread for sharing their knowledge. Your advice and tips helped me fix my late shifting problem with my M1009. My M1009 was shifting from first to second between 25 and 30 MPH. It shifted from second to third between 50 and 55 MPH.

Here is what I did to fix my problem:
(Refer to TM 9-2320-289-20, section 3-21 “Transmission Vacuum Hose Replacement”)
1. Remove the air cleaner and block off the intake manifold to prevent foreign object damage. I removed and replaced these vacuum hoses (item #1, #3, and #5). Vacuum hose #5 is actually two different size hoses spliced together with connector #6. My old hoses looked pretty bad!
2. I took the M1009 for a test drive and it still shifted late.
3. With the M1009 running, I disconnected hose #5 from the transmission vacuum valve (item #9). I placed my thumb over the end of the hose to see if there was suction. Since there was suction, I figured that my vacuum pump (item #2) was probably okay. I decided to bypass the transmission vacuum valve (item #9) by connecting hose #5 coming from the vacuum pump (item #2) directly to the metal pipe that leads down to the vacuum modulator on the side of the transmission.
4. I took the M1009 for a test drive and it shifted normally. This told me that my vacuum modulator that is mounted on the side of the transmission was probably okay.
5. I removed the transmission vacuum valve (item #9) from the fuel injection pump. (Refer to TM 9-2320-289-20, section 3-21.1 “Transmission Vacuum Valve Replacement”)
6. Valve Cleaning Process - I removed the plastic access cover on the side of the valve and soaked the parts in some Simple Green cleaner for about an hour. I rinsed the parts and worked the mechanism to ensure that it moved freely. I then soaked the valve in some WD-40 for about and hour while working the spring loaded mechanism periodically. I blotted the valve dry with some paper towels. I used a can of compressed air to blow out the plastic nipple fittings.
7. I put the plastic access cover back on the valve and mounted it back on the fuel injection pump.
8. I took the M1009 for a test drive and it shifted great! My M1009 was shifting from first to second around 15 MPH. It shifted from second to third around 35 MPH.
9. I decided to see if I could lower my shift points even further by adjusting the position of the valve. After a couple of attempts, I got my M1009 shifting from first to second around 13 MPH. It shifted from second to third around 32 MPH. I was happy with this setting.


When I was replacing my vacuum hoses I noticed that the rubber connector (TM 9-2320-289-20, section 3-21, item # was cracked and dry rotted. So, I connected my new vacuum hoses directly to the plastic nipples on the vacuum valve. This worked okay even though there wasn’t much clearance between the 2 vacuum hoses installed on the plastic nipples. Does anyone know where I might find a new rubber connector?

Thanks again for the great tips and advice!

Jeff

Thanks Jeff, I was just planning on working on the lines today, and came back to re-read the thread and found your incredibly useful post... Now I don't even have to think to do this!

I bypassed the vacuum valve, by hooking the vacuum modulator straight to the vacuum pump. As far as I understand, this should make it shift soft and early, it does not. It still shifts 1-2 at 35mph, and no 2-3 shift at all, even at 60mph. I have more than 20hg at the vacuum pump, and with the vacuum lines ran correctly through the vacuum valve, I have about 10hg at the vacuum modulator. It is also a new vacuum modulator. What do yall think?

Also, all new vacuum lines.

Just had the same issue with my 1009 changed vac lines shifts perfect now

raiburn said:

I bypassed the vacuum valve, by hooking the vacuum modulator straight to the vacuum pump. As far as I understand, this should make it shift soft and early, it does not. It still shifts 1-2 at 35mph, and no 2-3 shift at all, even at 60mph. I have more than 20hg at the vacuum pump, and with the vacuum lines ran correctly through the vacuum valve, I have about 10hg at the vacuum modulator. It is also a new vacuum modulator. What do yall think?

Also, all new vacuum lines.

Click to expand...

I think you are on the right track. I would try replacing the vacuum modulator. I don't think they are too expensive. Let me know how it turns out. - Jeff

Jeff, It has a new red stripe vacuum modulator.
I also just removed the governer from the trans for inspection, it looks great, and moves freely. I'm lost.