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greenStar

1986 International CargoStar - Automatic tranny problem??

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1986 International Cargostar - Allison auto tranny problem?? And power steering gearbox shaft leak.

Hi guys. I'm new here. I just picked up this clean orange 1986 international cargo star with the DT466 and an Allison automatic transmission, it's the perfect truck for what I need and I want to get it going. The transmission felt fine when I tested it before buying it at the auction, it shifted from neutral to drive, to reverse, to drive and back smoothly with no clunking..and was very responsive and felt good... BUT now I am unfortunately discovering after buying it and driving it down the road home that it won't shift from gear to gear automatically. It won't stay in overdrive (5th i think it is). I can get it to run in overdrive if I shift up to it and then am not on a hill and if I'm not pressing the pedal too hard, but otherwise it keeps coming out. It also will not shift from any gear to another gear. I have to shift it all manually. It doesn't shift right basically. Could this hopefully be something other than the torque converter or transmission itself.?

I would really like to avoid a transmission specialist telling me that it needs a $3,000-4,000 transmission or torque converter rebuild and replacement, if possible!?!? (fingers crossed!)

My question for any of you experts is could it be something like a trans computer or a speed sensor , or some other sensor or something other than the tranny itself? Is there anything like that you guys know of? I am reluctant to bring this to a transmission place before I know the answer to this question, because I know what they'll most likely say of course. Do any of you guys know much about this set-up?
Is there any such thing you all have heard of that would cause such a problem?

The fluid actually looks very cranberry colored, and does not smell bad in particular, although it looks very milky, whitish, like some cream was poured in there or something, basically that type of color, but again, not low or doesn't smell bad at all . Someone told me that that could be from a little water getting in though.

Any professional opinions? ?

Also, the power steering gearbox is leaking through the shaft seal right up against the frame rail there. I wonder if that's a simple rebuild where I can just get a seal someplace and just take it apart and fix it for cheap ... Or is that some hard project and difficult thing for an average mechanic to do and I'm better off taking it someplace who rebuilds such specialty items, or do I need to just put in a whole new remanned one , and will cost me a lot to find a part that's rare. Basically guys what's the easiest and cheapest way out of this one?

Thanks. The truck is awesome! I'm very excited about it!

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Nice loader! a Hiab? Very handy for your kind of work. Sorry I can't answer your question

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Call you local Navistar dealer and talk to the service manager. They should be able to help you out. There were tons of buses out there with a Allison auto so a used tranny could be bought reasonable. Good Luck. Eason

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Greenstar

The whitish milky color that you have in the transmission is coming from water in the fluid. Change the fluid and if you have an oil cooler on this truck, I would unhook the lines and flush out the cooler oil so that you get as much water out as possible. I would suggest that you pull the lower torque converter cover and check the converter for a drain plug, not all models of the Allisons have a drain plug. If your converter does not a drain plug I would start the engine after removing the oil pan and filter. Just let it run momentarily and keep a drain pan under the transmission. Please get the water out when the transmission fluid is warm and don't allow the truck to set around with contaminated fluid. The water will freeze and this will increase the visosity ( thicken ) of the oil, this will not allow the transmission to shift properly and can cause corrosion to the metal components.

As for the upshifting problem there is a modulator that is hooked to the engine throttle, this allows the transmission to know what you are wanting the engine and transmission to do. This adjustment can be tuned to each owners and trucks occupation and wishes.

GT&T

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GT&T,

Would the water in the fluid cause it to have shifting problems, even after the truck had been running 20-30 minutes and the fluid was completely warm?

How can I figure out if the modulator is the problem? Any ideas?

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edwardporter1,

No, its a Palfinger PK7000, and it has a 30' reach!! Yes, this truck had my name written all over it. I was ecstatic when I saw it and had to have it!! Exactly what I need! Especially for where I work so often in the city.

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I think it says it's a T465 Allison MT650 5 Speed

but I am going to try to further confirm by crawling underneath later..

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GT&T,

Two questions.

Do you think that even after running it for the 20-30 minutes that the water in the fluid and converter could still be preventing it from shifting and running correctly?

Also, Where is the modulator on the engine throttle, and how is that adjusted please? Thank you for your help.

Its a MT653 transmission.

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If you end up needing the transmission diagnosed and or repaired

I used this outfit years ago when I was too busy to rebuild the unit myself

they did a great job jim maclaughlins Truck and auto repair Lynn Mass

The modulator control should be mounted very near your throttle connection it will be a "morse style cable"

as you open the throttle the cable should push in ,Basically it controls the upshifts , the more throttle you give it the longer it

takes to upshift, One tip make sure you are getting full travel ,no slop, etc, on you throttle and modulator cable linkages

Nice Truck !! See you around

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Greenstar

If you have had water in the transmission fluid for a period of time, then the water could have corroded the iron parts in the valve body, as well as plug ports and orfices. This sludge may be plugging the filter as well as the pencil screens in the governor oil supply tubes.

The modulator is located in the transmission and is operated by a Moorse cable that should be hooked to the throttle linkage at the injection pump. If you have someone operate the throttle pedal and look under the cab you should be able to see the throttle linkage moving, there should be another cable hooked to the throttle lever that goes to the right rear corner of the transmission. This linkage should move when the throttle pedal is operated. The modulator linkage is held in the side of the transmission by a clip and one bolt.

If by chance this transmission has been changed with a used one out of a gasoline engine equipped truck and has not had the vacuumn operated modulator removed, then you will see a "can affair" at this location. The vacuumn modulator will be about 3" in Diam. and 4" long. If it, by chance has a vacuumn modulator, you will have to have a cable type of linkage installed.

Check the modulator linkage and see if it's hooked up and operating as this linkage tells the transmission what you want the engine and transmission to be doing.

The linkage should be adjusted to allow the transmission to up shift at the engine RPM that you want it to.

Get back in touch after you find out what you have. You will need to change the transmission fluid and filter. I would unhook the oil cooler lines and flush the oil cooler out to remove as much of the contaminated fluid as possible. I would also remove the lower torque converter cover and check to see if there is drain plug for the converter. If possible drain the converter to get out all the contaminated fluid as possible.

While you have the oil pan and filter off, I would also remove the governor oil supply tubes and remove and clean the pencil screens. If these screens are plugged the governor will not be able to supply the necessary oil pressure to upshift the transmission.

You have asked "what time it is" and I have told you "how to build a watch".

GT&T

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Greenstar

Kevin and Eason have some good information as well. Kevin has done a good job of expaining what I was trying to say. He must have been posting as I was writing my post.

Hope this helps.

GT&T

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The best thing for you as a new owner to-do is to get the owners manuals for all the features of the vehicle and learn how it is supposed to operate.

Take the rig to the closest Navistar Dealer and have them do a comprehensive inspection.

They should have someone with experience on this model and an allison expert.

This is a commercial truck working in a business, safety and other inspections will be required, dealers have all the information required.

I don't know what the rates are in your area but I expect $150. would cover the labor.

A new piece of equipment needs a professional evaluation.

No more guessing, actually cheap advice in the long run.

Their recommendations for service is probably reasonable, they do have a reputation to maintain.

Their employee would also be a good source for "a cheaper way to repair it" ideas.

Our old Cat Powered Freightliner (1999) was back at the Cat dealer this month.

It is in Pensacola Fl for Christmas 2014.

The 3406E was throwing up codes and not at 425HP.

They did a code read and replaced at least one sensor.

Bill was less than $500.

Many of the commercial dealers are very competitive with private shops.

Just part of the cost of operating your business.

Looks like a very nice rig. with the right equipment for your business.

Does it have alot of hours/miles on it?

Good luck with your rig.

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Oleman ,Is giving good advice , Maclaughlins is most definitely a factory authorized Allison repair and parts dealer '

If you would like to go to an International Dealer I would recommend Taylor and Lloyd in Bedford Ma

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