M1009 Hard Shifting tranny, first post

[24farragut]

Just got a 1985 m1009 home from lakehurst naval air station in jersey. The truck is in great shape, the engine runs perfect, new batteries, filters, belts, leaf springs, headlights. Seems like i really lucked out. The only issue i have is the tranny slams really hard into gear, and doesnt shift until the rpms are extremely high.

I checked the fluid. it is brand new, and full. I heard something about a vacuum pump on the tranny, has anyone adjusted one of these before?

thanks fellas.

 

[Westech]

you cant adjust the factory one.. you have to buy a B&M one, there about 40 bucks. you can adjust the vac controller on the side of the injection pump. play around with that and see if you can adjust the shifts a little with that. and last note make sure all the vac lines are good and hooked up. no vac will cause that problem too

 

[maritimer]

if it has the th400 which it should theres a vacum modulator on the passenger side of the trans that has an adjustment screw in it to adjust shift points,

 

[beaubeau]

I had problems with mine. I found a Vacuum line broke completely off the vac. pump. I re-hooked it up and it now shifts great. Check your vac line salll the way to the Tranny. You might want to take the cover off the govenor and be sure nothing is STUCK. I would check Vac lines first.

 

[ssgtwright-usmc]

If you tried the above and still have the problem then try changing the fuel filter.
I had the same problem, replaced the modulator, transmission filter, vacuum hoses and ect and still had the problem.
When I replaced my fuel filter the problem went away. I must have had a clogged fuel filter but right now she is running fine.
I never thought about the fuel filter since I do a regular maintenance on mine, changed oil, filters and ect 2 months prior to mine having the same problems you are describing.
Luckily someone here suggested that I should change the fuel filter and my problem is gone for now. My filter was changed during my maintenace period also.
Funny how a clogged fuel filter can cause you to think that you are having a transmission problem when the tranny is fine.
Keep us posted on what you find and what you have done to fix the problem.

 

[CARNAC]

First download the technical manuals (TM) for the CUCV from the resources on this website. You will find the troubleshooting in the TM ending in -20 and -34. Parts manuals end in a -20P and -34P.

Change the modulator after looking at the -20. It's a level one, quick 5-10 minute fix. If you still have issues, check the line that runs from it from end to end or just outright replace it. I suspect that if you knock out those two, you will have fixed it. If not, drop the transmission pan and visually look for anything out of order such as metal on the magnet. Replace the filter, reseal it and try it out. This should take easily less than 30 minutes and is also a level 1 task in my opinion. If none of this helps, then I'd come back on here and ask for help or keep following the -20/-34 TM's.

 

[ClockworkSkin]

I apologize for this as it is probably a question that has been covered but I haven't been able to find it after searchign high and low. I want to replace the vacuum lines because I'm having the shifting problems that seem to plague so many new owners but I cannot find what size lines I need to get. Does anyone know the size/type of lines that I need, or eve have any reccomendations for where the best place to get them is (Advanced/PepBoys etc)?

Thank you.

 

[84cucv1ton]

i replaced a vacuum modulator once. never gave me any problems after that

 

[m38inmaine]

Check the vacuum lines, modulator and vacuum pump first, if they are good next would be the vacuum valve on the side of the injector pump, these go bad as well and are used to adjust the timing of the shifting.

 

[ClockworkSkin]

I know for a fact the lines are dry rotted. They need replaced either way. I want to repalce them first because it should be a quick fix, and cheap. After that I will look at other things (VacPump etc). I just need to know what size lines I need to buy. I think they may be 3/16" or possibly 3/8".

 

[CCATLETT1984]

its the lines, i'd bet money on it. just cut a piece of line off and go to the parts store.

 

[ClockworkSkin]

I guessed with 3/16" and it ended up being right. The best part is that $5 of rubber hose fixed my shifting problems. I was extremely happy when it shifted to 2nd at 20mph.

I would say that replacing that hose should be added to S.O.P. in addition to changing fluids etc. From doing searches it seems that everyone has that problem.

 

[beaubeau]

I am glad for you it was an easy fix. I had a light issue with my M1008, and I solved it today. It seems the N.J. NG installed a new exhaust on the vehicle. I noticed the L tail pipe hung LO. Well I jacked the truck up, {With Excavator}, and I noticed the pipe was too close to the frame and the pipe was touching the wire harness to the rear lights. The wires for L turn signal would keep Shorting out. I straitened the exhaust and fixed the lights at the same time. The Dog is that this same thing happened to my other M1008, at just about the same spot. All turned out to be an easy fix. Good luck with your M1009, Phil

 

[tc97]

cucv trans vaccum lines

86 M1009. 44,000 miles.

Developed hard shifting and high rpm shift.

Checked & changed vaccum lines per this forum.
(Soft, spongy & cracked)
Took about 30 min.
Now shifts smooth and on time.
Tks forum members for posts.

 

[charlietango]

alright fella's I have a problem. Last fall I found a bad vaccum line and changed it (#5) and it started shifting like a champ. This past August it started shifting a bit late again so I figured, easy! I will just change all the rest of the lines and be done with it. Well I changed all the remaining rubber hoses #1, #3, and the rubber seal at the transmission that connects #10 to the regulator at the trans. took it for a spin and wow it wont even shift out of first now! I noticed that the rubber block (# 8 ) on the vaccum pump assembly looked pretty rough. So I bypassed it and hooked the #1 to the top plastic nipple of the pump assembly and #5 to the bottom nipple direct. what the **** happened that it was shifting late and now wont shift at all?? I triple checked all my work and the hoses are attached to the right places. I did a vaccum check pulling #5 off and the block mounted vaccum assembly was pulsing air, re assembled same problem.

 

[raiburn]

Mine has this same late shift symptom,(shifts to 2nd at 35).
I have not changed the vacuum hoses, but I do get 10 inches of vacuum at the new Vacuum Modulator at idle. No change when I replaced the Vac. Mod.
Does anyone know which direction to turn the adjustment screw in the Vac. Mod. to lower the shift points?
Also, how do you check the vacuum valve on the IP?
I tried bypassing the Vac. Valve, thinking it would shift way too soon, but it did not. Same late shift.
I'm lost. Joe.

 

[chief1983]

20 mph? I wish I could get a 2nd gear shift at 20 instead of 25, but I'd _really_ like to get a 3rd gear shift at 35-40 instead of 45. Almost every road out here is 35, or 55, so having to hit 45 to get to third gear is a PITA. If I can make the TH400 shift sooner I'm gonna have to investigate that farther. The shifts aren't harder than they should be for a HD transmission, just too high. Would also like any info on the TH400 shift adjustments, I'll dig through the -20 and -34 in the meantime though.

 

[cleb]

Replace the lines, then the modulator on the IP. The plastic modulator gets old and leaks. Check for vacuum from the pump. If there is none, or not enough, replace the pump itself. I had 3 pumps die on my CUCV.

 

[ralbelt]

M1008 shift points at 12 and 22, I have replaced every piece of rubber, modulator, new trans filter and oil. Nice and smooth can't even feel the shifts. Sometimes it does not drop into first , the first one or to start and stops, once it warms up no problem at all.


First rule of owning a CUCV.If its rubber replace it, if its electrical clean it.

 

[kipman]

Doghead has the part in the classifieds that may fix your problem.