1986 International Cargostar-Allison auto trans problem? And power steering box leak

greenstar

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

Hi guys, I just picked up a clean 1986 international cargostar cabover with a DT466 and Allison automatic transmission, it's the perfect truck for what I need and I want to get it going right. I was very excited about the truck when I first bought it. It seems clean. 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 to drive smoothly with no clunking..and was very responsive and felt good when pulling it forward and back 10-15 feet in the parking lot... BUT now I am unfortunately discovering after buying it and driving it down the road 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 going up 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 is basically what I'm saying. 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 or replacement job, 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 modulator 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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stealth13777

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Well I can't help with your questions (other than to say yes, milky color in trans fluid usually means water), but I will say that truck looks sweet. Nice find!


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snicklas

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I agree here, nice truck. I love the old IH stuff... I collect and use IH Cub Cadet garden tractors, and plan on owning an old Binder Scout or Pickup sometime in the future. Being an 86, it is one of the last IH branded trucks, as the IH Ag line selloff to J.I Case (TENNECO) happened sometime in late 85 / early 86. I think in 87 was the one an only year you actually saw a Navistar branded truck. No one would buy something they never heard of, the next year they started using the name: International Truck and Bus Company, a Navistar Corporation. The truck/bus/engine division that is now Navistar is truly the only part that is left of the original 1900 IH/Farmall company. The International Harvester name, and the IH "Man on a Tractor" logo were sold as part of the Ag line selloff. This is why they were/are CaseIH, because they bought the name. The original company changed its name to Navistar due to the name selloff....... (Sorry, have really followed the IH history over my lifetime, because I remember IH still being in business and seeing these and the lightline trucks sitting on the lot at the local tractor dealer.)

Again, nice find. Hopefully someone will be able to help on the transmission. I would say being that age, there isn't much, if any electronic control on that Allison. It more than likely is a mechanical/vacuum control system, much like the C-6 in the early Ford IDI's, vs the E4OD electronic transmission in the late IDI's. May be something as simple as a vacuum line unhooked, or a control lever has slipped out of position. I would say if it is just a shaft seal, it should be able to be replaced. On the pickups, several member have replaced seals on leaking steering boxes with some success. I would say a medium duty part should be serviceable this way, as it is a "real truck" not a pickup. (No offense to the pickups guys) They were designed to be fixed as quickly and easily as possible and put back on the road, because most of them were used to make a living, not just to get somewhere. If it is anything like everything else that IH built or spec'ed, it will be overbuilt and serviceable. IH never used the "its good enough" idea to make anything........
 

greenstar

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Snicklas, when you say a "control lever" has slipped out of position, now is that something that's inside the transmission?? or is that something that can be accessed and fixed without having to take the transmission out?
 

snicklas

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I am not 100% sure. I have only driven a couple of medium duty trucks with the Allison transmission, never worked on them. I am just going by the era, and how the light duty did things to control the transmission. I drove an Early 80's Loadstar Single Axle Dump Truck with a 3208 N/A Cat and an Allison. (It was a retired Illinois DOT Truck, I worked for the local township.) This truck had a "gear shift" with a T-Handle and different gear selections. R-N-D-3-2-1 I think, been a looong time since I have driven it, and it was all mechanical or vacuum controlled. We had a newer truck, built in the 90's with an Allison, and it had pad with buttons to select the gear, and a display to show what gear it was in. This one was electronic controlled, I believe. I am talking about a line/cable/rod that is external. That is where I would start if I was in your situation. I know on the C-6 in the 80's pickups, if you have vacuum issues they shift "funny", and it the kickdown rod is off, or out of adjustment, it doesn't like to downshift....... I would say the fact it moves is a good sign, and that all the gears work. So it sounds like a control issue at this point, rather than an internal issue. I may be wrong......
 

greenstar

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maybe it is slipping a bit, it won't stay in 5th and keeps dropping down.

I have to shift it from D, to 1, to 2, to 3-4 or 3-5 position on the dashboard. It is a "T" shaped shifter that sticks out of the front of the dashboard
 

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