My newly aquired 86 CUCV M1009 transmission is going out.

[1073CJ5]

Just bought my 86 M1009 today and first day the starter hung up at the DMV and stayed on for about 30 seconds before letting go. Hasn't done that anymore...When backing out of the DMV I noticed that I had to give it alot of gas to get it to back out of the parking spot. I tested the reverse gear a few times and it looks like the reverse gear and possible the 3rd gears are going out. I attempted to back up a small incline and she failed to get up it, foreward, no problems, but reverse was a no go. I then attempted to go up in 4H and again a no go. I then put it in 4L and she backed up the incline NO problem. On the highway it seems like the 3rd gear might be going out, not sure but maybe, takes forever to shift up into HI gear. The fellow I bought it from feels bad and wants to make it right and offered to either take it back or reimburse me for transmission work. Posting to see what you guys think. If you have had similar issues with the auto tranny in the M1009. Vehicle is really clean (no rust and 67K miles) . Recommendations for rebuilds of replacements. Im in Alaska BTW in case anyone knows some parts/shops etc.

Thanks and look fwd to everyone's expertise.

Billy Jack

 

[MarcusOReallyus]

Just bought my 86 M1009 today and first day the starter hung up at the DMV and stayed on for about 30 seconds before letting go. Hasn't done that anymore...

First thing you want to do is the doghead starter relay mod. Check the stickies for details. When that starter relay goes bad, it can wreck starters and burn up wiring. The doghead mod is a $17 cure for the problem BEFORE it costs you hundred$.


Sounds like that trans is going, going..... But do check your vacuum hoses - that can cause the delayed shift issue. Nothing to do with slipping, but you likely have multiple issues.

Congrats on your new toy!

 

[SandBar]

My dodge 2500 has a similar behavior. When first started after sitting a while it takes the transmission 5-6 seconds to develop full pressure. I thought it was toast so I took it to my local trusted transmission shop. He checked everything out and said that this model of trans in particular tends to leak down pressure when sitting after 100K miles or so. 35K later, same behavior and works great other than that. Not saying it is the same exact cause but an idea. If you end up swapping the transmission the 700R4 from the civilian K5 6.2's have more clutch packs and are built a little tougher. Nice find by the way, they all need work of some kind.

 

[Skinny]

Sounds like the direct/reverse clutch is failing. I would service the fluid and filter, pay very close attention to the level adjustment. If that doesn't solve it, you will have to tear down and rebuild it.

I'm not too familiar with rebuilding a TH400 but you could invest in a pressure gauge set and see if that clutch pack is getting enough pressure to operate. It could be a valve body issue as well. More than likely the clutch is failing but you want to eliminate anything that may be causing it without having to do a full rebuild for no reason.

 

[RedneckMilenko]

Check your trans fluid, if it seems dirty or "burnt" then you have some bigger issues. If not then you may have a smaller problem. Like Skinny said, it sounds like your reverse clutch is going bad but if you check your vacuum system and all is good your pump inside the transmission could be going out, have something blocked off in the valve body, or you may just need to do some adjusting to your modulator valve to cure the long shift into 3rd. The cheapest things you could do to try to fix the problem without a rebuild would be to change the trans filter (it's easy as can be) but make sure you fully install the pick up tube into the filter and the trans. If ot then you will lose pressure and will burn up the trans. to see if your modulator is bad you can pull the vacuum line off of it and see if there's ant trans fluid coming out of the modulator. May still be bad eve if there isn't any fluid but it's only about $10 at autozone so it's not that big of a deal to replace.

 

[Scarecrow1]

I am not and never will claim to be a transmission mechanic so I am of little help to you but, I had to tell you whom ever you bought the truck from sounds like a stand up guy. You are far luckier to have found him than the truck. Having said that you may want to use the same good judgment and have it checked out by the pro's. It may be a little thing or a total rebuild let them make that call. Now I have dropped in a can of break fluid into a civi chevy blazer with a slipping problem and drove it until last month when I sold it 12 years later. Good luck to you and your truck .........

 

[cameron8757]

I had similar issue but mine was 1st gear when it was bellow 30 in the morning. I tore it apart and all the seals were hard from sitting and age.
$100 in parts and good as new.