1986 6.9 L
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1986 6.9 L
I have just acquired a solid F-250 6.9L 4X4 with a 4 speed manual tranny. I plan to keep this truck for a while and will be restoring it over the next few months. Aside from needing an axel seal and a new fuel pump in the rear tank the unit seems in great shape. My long term plans are to replace the transmission with a 5 spd or OD unit. What will bolt to the Navistar 6.9 L w/o a great deal of trouble?
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From: Bashaw, Alberta
1986 6.9 L
I haven't had any problems with my tranny, but mine is in an F-250 which is probably got a stronger drivetrain than a 150. We have two ZF's one behind a 7.3L deisel 1989 and one behind a 460 1988.
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From: Fort Wayne, IN. USA
1986 6.9 L
Aside from needing an axel seal and a new fuel pump in the rear tank the unit seems in great shape
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1986 6.9 L
Thanks for the tip. I can run for only a few minutes after switching to the rear tank and then the truck dies. I had a similar problem with my 1988 F-150 which I traced to the electric pump in the rear tank. I assumed that the diesil would be a similar system so thanks for saving me from dropping the rear tank.
I have noticed that the gauges are also acting funny. They will not read anything at first but start working fine after driving for an hour or so. I will have to get into the dash and go through the wiring. The previous owner had a bad habit for adding electric lights and do-dads all over so the wiring is very scary. I will be pulling the box off and building a deck for the truck soon so I will check all of my tank sensors and the switching valve then. I just ran it 250 miles at 65-75 MPH and averaged 22 mpg. Not bad for a truck with 247,000 miles on the clock.
I have noticed that the gauges are also acting funny. They will not read anything at first but start working fine after driving for an hour or so. I will have to get into the dash and go through the wiring. The previous owner had a bad habit for adding electric lights and do-dads all over so the wiring is very scary. I will be pulling the box off and building a deck for the truck soon so I will check all of my tank sensors and the switching valve then. I just ran it 250 miles at 65-75 MPH and averaged 22 mpg. Not bad for a truck with 247,000 miles on the clock.
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From: Bashaw, Alberta
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1986 6.9 L
The box is rusted over the wheels and at the lower rear corners but in general it is fairly solid. I have found that for the additional cost of repairing and painting a box I can build a pretty good deck. We have a small farm and the deck is much more versatile than a regular box.
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From: Evansdale
1986 6.9 L
Originally posted by Alberta dave
Are all ZF 5 speeds the same for Fords or did the diesils take a different model? I remember hearing some reliability complaints about the 5 speeds in 1/2 tons.
Are all ZF 5 speeds the same for Fords or did the diesils take a different model? I remember hearing some reliability complaints about the 5 speeds in 1/2 tons.
Some 5 spds in the 1/2 tons could be mazda trannies, something to keep in mind... but yeah the zf tranny has pretty weak synchros, prone to mess up
