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TH400 auto trans for heavy duty work


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mbavers
User

Jan 9, 2016, 2:50 PM

Post #1 of 11 (1105 views)
TH400 auto trans for heavy duty work Sign In

I have a 1984 M1008, which is a military Chevrolet pickup, 11/4 ton, 6.2L diesel, TH400 auto. I used it a few times for plowing snow and it gave out (no reverse, slips in forward drive). No trans cooler, and it had been misused when I bought it. I am going to have it rebuilt, and am wondering if it pays to pay extra to have it rebuilt to higher specs than stock. I think the original problem was overheating, which I do not think would be helped by a "super" rebuild. I do plan on installing a cooler, so would a standard rebuild be good enough?


gsferraro
Enthusiast

Jan 9, 2016, 7:44 PM

Post #2 of 11 (1096 views)
Re: TH400 auto trans for heavy duty work Sign In

Hello,
400 Trans is pretty strong in my opinion, i would certainly put a cooler on it, is this a 4x4?


mbavers
User

Jan 9, 2016, 7:52 PM

Post #3 of 11 (1094 views)
Re: TH400 auto trans for heavy duty work Sign In

Yes, 4X4


gsferraro
Enthusiast

Jan 10, 2016, 7:34 AM

Post #4 of 11 (1074 views)
Re: TH400 auto trans for heavy duty work Sign In

If you can, put the transfer case in low range when plowing, it will take some stress off of the trans. Gary


mbavers
User

Jan 10, 2016, 11:44 AM

Post #5 of 11 (1062 views)
Re: TH400 auto trans for heavy duty work Sign In

I had been doing that, but since it then goes through more shifting I was wondering if it wouldn't be better to stay in 4H and maybe avoid having the trans shift into 3rd.


gsferraro
Enthusiast

Jan 10, 2016, 11:59 AM

Post #6 of 11 (1061 views)
Re: TH400 auto trans for heavy duty work Sign In

When plowing how fast do you go? I would say if the snow is lite 4H would be fine, but if its heavy i would go 4L, do you plow large areas?


mbavers
User

Jan 10, 2016, 12:07 PM

Post #7 of 11 (1058 views)
Re: TH400 auto trans for heavy duty work Sign In

I plow my road, about 1 mile, plus around my house and a couple of parking pads. I guess on straightaways where I can go fast I'll use 4H if snow is not too heavy. What you are saying sounds reasonable..................thanks.


gsferraro
Enthusiast

Jan 10, 2016, 5:03 PM

Post #8 of 11 (1049 views)
Re: TH400 auto trans for heavy duty work Sign In

Your Welcome.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jan 10, 2016, 8:48 PM

Post #9 of 11 (1044 views)
Re: TH400 auto trans for heavy duty work Sign In

Note on plowing for both of you: 1 - Gary, totally agree it that low would be easier on a trans.
No joke, been plowing for almost 50 years! First with a farm tractor doesn't count. Next '84 S-10 (700R) and now '97 C/K 2500 (4L80E) but 99.9% driveways and some long. If I use "L" the trucks leap frog into second gear plus are goofy to turn around in a plain wet street which is normal. I use 4H most of the time and plain (OD) on shifter as think at such low speed it's in low gear only anyway.
This can only be individual need and type of plowing IMO. I will begin and it's mostly the weight* of the truck for first contact and barely need throttle and again let the inertia of truck make the pile at end if not just tossing snow to the side so far so good don't think I'm hurting transmission and would be a disaster for any breakdown.
I worry more about all the shifting forward and back so the underside linkage is spray greased whenever I'm at it year round.
Did a couple times plow a mile plus road but as a passenger if not looking you wouldn't know it was plowing so easy on the vehicles.
Just those times if a place has old storms well set and another snow on top use "L" and need more speed (still not much) than I like and think it's working it probably going to bend something rather than harm the trans.
******************************
OK: Seem odd but pay attention to heat!! Grille can pack up and air can't get thru and trans cooler (extra and in radiators) is or can block up.
I watch others unknown to me just go slamming around bullying thru snow banks, stuck w wheels digging holes and just wonder but you know it isn't their truck!
*****************************
Got caught last season at the area of the most (super light) snow of anywhere USA including all of Alaska. FOURTEEN FEET included 3, 4 FOOT blizzards in a row! I also plow constantly during a snow so never all of it all at once.
Trans fluid: Synthetic
Eng oil: Shock but 0-30 synthetic rated for it hold oil pressure up year round even at idle! OK - 59K orig on the truck, 5.7 Vortec oil cooler and was new with plow ready options.
* Said using weight of the truck (open bed) and do NOT add stuff for weight only because it gets frozen in the bed and pest to shovel out bed when it's all over.
Gary - Just the feel I don't think even in that extreme I was harming it, just lots of use and did lose area to existing snow piles that only a front end loader could have moved.


This is West of Boston at the edge where many snows will end in rain and be a real pest but not the Winter from hell here but did closer to ocean.
Point is from me I think driver can tell if they are being hard on trans and vehicle in general. Can't speak for others but say even plowing driver just has to go easy. Gary again - we are only perhaps 200 miles from each other and snow where you are plenty too. Bet your shop was full of all sorts or drivetrain problems and worse - wait two days for the underside to melt down so you could see anything!
Other note for any vehicle in snow and Gary please agree or not: Do NOT rock a vehicle forward to reverse to get unstuck? It works but think that rapid switch is real hard on a trans.
Cross fingers - have not ever had to redo a trans on a plow vehicle of my own but close w the '84 S-10 which was iffy when I got it free w 160K or so!


PS: Total record of all time last season. Last snow pile (Lexington, MA) finally dissappeared July 14th - a snow farm from streets of closer to Boston!
Tom



gsferraro
Enthusiast

Jan 11, 2016, 4:43 AM

Post #10 of 11 (1033 views)
Re: TH400 auto trans for heavy duty work Sign In

 I agree, do not rock a vehicle foward and reverse to get out of the snow, when my customers ask me(after i put a trans in there car) "how do i get out" I tell them to get out and dig.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jan 11, 2016, 5:04 AM

Post #11 of 11 (1031 views)
Re: TH400 auto trans for heavy duty work Sign In

Thanks and sorry for the book I wrote above. I was taught both tech school and trans techs the same. I bring this up because I think it's harder on an auto trans than plain hard driving. I'm sure you'd like the extra biz but seems true. Habit, anytime is shift slow in any vehicle from forward to reverse.
Note: Real printed instructions in a FORD owner's manual for the years of the Panther body which I still own. States in plain English to rock between D and R to get unstuck! I'm shocked they printed or suggested that for any.
For anyone: A good trick is don't let wheels spin, hold brake. Give a little power not lots and release brakes and if nothing try tapping on brakes can confuse the slipping wheel(s) to shift power to one with some traction.
Laugh but it's not funny when it's YOU stuck. That and the shovel and sand with you if the issue is snow or ice. If that stuck call for a tow out it's cheaper and better for the vehicle,


Tom







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