1986 6.9 L
Thread Starter
|
New User
Joined: May 2003
Posts: 19
Likes: 0
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?
Senior User
Joined: Mar 2003
Posts: 337
Likes: 0
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.
Senior User
Joined: Jun 2001
Posts: 295
Likes: 3
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
Thread Starter
|
New User
Joined: May 2003
Posts: 19
Likes: 0
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.
Senior User
Joined: Mar 2003
Posts: 337
Likes: 0
From: Bashaw, Alberta
Trending Topics
Thread Starter
|
New User
Joined: May 2003
Posts: 19
Likes: 0
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.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 6 Best Deals Available on New Fords & Lincolns Right Now
Brett Foote
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Verdad Gallardo
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
New User
Joined: May 2003
Posts: 17
Likes: 0
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
