M1008 tranny troubleshooting help needed - Steel Soldiers::Military Vehicles Supersite

LanceRobson · 08-02-2008, 15:01

I'm working my way through the -20 and -34 manuals and the archived threads trying to get through troubleshooting an M1008 tranny.

I picked the truck up from Lakehurst last week and it wouldn't shift into either reverse or third. First and second act correctly and shift at what seems to be the correct speed for throttle position.

The coolant temp and downshift connectors were disconnected and dirty with road grime. The glow plugs had been cycling continuosely. A wire to the switch on the transfer case was butt spliced with a non-waterproof splice and had come apart.

The tranny fluid level seems OK and the only other thing I can think of is that the fluid is, maybe, a little light in color. I'm wondering if there is a possibility of an ignorant soldier adding 10W, since I'm told the M939s use it. I'm going to change the fluid and filter, but need to take a better look at the connector for the downshift switch. The -34 manual shows the pan off and the filter out to replace it and, as is, the harness plug will not latch.

The fluid does not smell burnt or look burnt.

I've replaced all the vacuum lines. The vacuum pump puts out 26-27 inches of vacuum. 13 inches from the switch on the IP, ditto at the modulator. The -20 manual isn't really helpful in that it staes to check the hoses, rplace the vacuum pump etc. No real data on detailed troubleshooting.

The tranny has a new modulator.

The rubber CDR Tee connector is rotted into fragments and has been long enough that the right side of the intake manifold and head are slimey but I can't for the life of me see a connection to the tranny.

I realize the tranny may be flopped out, belly up with the buzzards starting to circle overhead, but any advice would be helpful.

Thanks

Lance

CCATLETT1984 · 08-02-2008, 15:27

pull the pan, look for friction material in the fluid. change the filter and put new ATF in, its not an expensive test.

As to the CDR Tee, I have one i could send you. (I'll make sure i have it tomorrow)

crusty · 08-02-2008, 18:33

One of the clutch packs in the TH400 is engaged in both High gear and Reverse, so I wouldn't be surprised if you needed an overhaul. Clean, unburned fluid usually is a good sign, but sometimes it just means that someone changed the oil to try to solve a major problem - unsuccessfully.

papercu · 08-02-2008, 19:58

I agree, on the chevy I owned whan reverse goes, it's time for a rebuild. If you are going to use it a lot, invest in a good cooler. Wayne