Re: [MV] M1009 transmission help...

From: Glenn Shaw (wolf.star@verizon.net)
Date: Sat Jun 14 2003 - 15:04:09 PDT


Hi Nathan

I have had these trucks and 3L80 Hydramatic transmissions for years and
rebuilt them also. It is a VERY heavy duty transmission. Standard
equipment in large Winnebago Chieftain Motor homes with the 454 gas engine
years back. Standard in the Mil Humvee etc. I can give you some of my
experience on these units. Answers within:

----- Original Message -----
From: "Nathan Wilkens" <nathan.wilkens@asu.edu>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: Saturday, June 14, 2003 3:26 PM
Subject: [MV] M1009 transmission help...

> Let me give everyone the background story on my (latest) M1009
transmission
> failure...
>
> I bought my truck in Dec 2001 with transmission problems (it had high
miles,
> so I expected a rebuild was in order).

*Normal at high miles many times. You were correct.

I then took it to a local shop for a
> transmission rebuild - which cost a small fortune by the time it was done
> (and other 'things' were added to it, transfer case rebuilt, fix a leak in
> the rear main seal, ect). It completely failed again on Christmas eve
2002,
> with only 8000 miles since the rebuild. Although the 12 month warranty
had
> expired by a few days, the shop agreed to rebuild it again. Now, only
3000
> miles and 5 months later, it appears to have died again.

* A lot of transmission shops are staffed with hacks. Transmission rebuilds
can have NO short cuts on parts or especially cleanliness.

> My theory is that the rebuild shop used standard cheap-axx parts on their
> rebuild that simply will not survive in a 6.2 diesel application.

*Most likely. They should use original GM parts only.

  I do have the shift points set a
> little low (20 mph from 1 to 2 and 35 mph from 2-3) to reduce the annoying
> rev-up and gear slam from second to third that is common in the CUCV.

*Negative. That is the correct way to set it. The slamming shifting is not
correct.

> Since I have discovered that I am the only good local mechanic for my
truck
> (maybe it's because I care that it's MY truck?), I'm left with doing the
> rebuild myself. I've never done this before, but I was an Army trained
63B
> mechanic (so I've a bit of aptitude). My question now is, what type of
> rebuild kit should I get? I see several companies that offer various
> rebuild kits including B&M's racing kits. Should I use a racing kit? Or
> are there recommended heavy duty 4WD kits, for the slower speed rock
> crawling kinds of stuff that I will soon be doing? Also, do I really have
> to replace the torque converter if it's only 5 months old? (can I really
> clean it out good enough to re-use?).

*You can use Jet or B&M parts if you want or go with GM OEM parts. They are
all high quality. The torque converter does not have to be replaced but you
must flush the entire cooling loop to make sure ALL metal particles and crud
are gone. ALL. And if you decide to keep the TC then it MUST be absolutely
clean inside . Hard to do. Needs a lot of flushing. This is probably what
the shop did not do to rush the job and save money. VERY COMMON. It leads
to repeat failures in many cases due to valve body parts hanging up causing
improper line pressures leading to clutch pack and band failure right away
which in turn contaminates the system even more. For a transmission
overhaul to be bulletproof the entire system must be absolutely clean, all
lines, coolers, and the TC. Many shops will not reuse a TC after a failure
due to it being very difficult to assure it being clean. The companies that
rebuild the TC open it up by turning the weld on a lathe and split it open.
Then they MIG it back together when it is rebuilt and cleaned. If I had any
doubt about the TC I would replace it.

Glenn
MVPA
MTA NJ
M1043A1
M1009
M151A2



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