just a wondering...
New User
Joined: Dec 2004
Posts: 20
Likes: 0
That's a great question? I'm really interested to see what's out there. I have also heard that the 6.9 was used in several pieces of agricultural equipment i.e john deere self propelled hay bailers, and some combines. They say these engines were run @ 2150 rpm for hours on end, under extrem heat and dust conditions, for a few months out of the year and sat the rest of the time, and proved very reliable. I have also heard ( across the bar ) that the 6.9 was, originally a project between UPS and FORD MOTOR COMPANY to produce a high mile engine+enought power+reliability. Any input would be great.....REESE
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
That is a little different from a story I have heard several times from different people.
The 6.9 was originally designed by Caterpillar for a government contract to propell something like an APC. The original design was also to be able to run at a 4400 RPM redline with reliability. The contract was awarded to Detroit Diesel in the end and Cat threw the blueprints back on the shelf. Later IH was looking for a small to medium diesel design for a truck motor. Cat sold the design to IH who produced the 6.9 that started all this for our beloved trucks.
I have seen several Cat yellow 6.9 engines before.
I have no direct knowledge of the truth behind any of this.
As far as the IH truck trannies used in the larger trucks, they would not really be of any benifit to a pickup. Most of the larger trucks had five speeds and a direct drive high gear coupled to a two speed rear axle to get 10 forward gears.
That would be possible for a two wheel drive dually truck but you would have a hard time with a 4x4 finding a transfer case and all that.
A zf 5 tranny with an underdrive from Gear Vendors or US Gear would accomplish the same thing with less headache and probably cheaper. Also you could have a limited slip differential that you could not have with the 2 speed axle.
This would also leave out the overdrive that we all need with todays fuel prices.
Dollar for dollar I think the Zf 6 would be the best and cheapest route to get more lower gears and an overdrive with less fabrication of non existant parts.
The 6.9 was originally designed by Caterpillar for a government contract to propell something like an APC. The original design was also to be able to run at a 4400 RPM redline with reliability. The contract was awarded to Detroit Diesel in the end and Cat threw the blueprints back on the shelf. Later IH was looking for a small to medium diesel design for a truck motor. Cat sold the design to IH who produced the 6.9 that started all this for our beloved trucks.
I have seen several Cat yellow 6.9 engines before.
I have no direct knowledge of the truth behind any of this.
As far as the IH truck trannies used in the larger trucks, they would not really be of any benifit to a pickup. Most of the larger trucks had five speeds and a direct drive high gear coupled to a two speed rear axle to get 10 forward gears.
That would be possible for a two wheel drive dually truck but you would have a hard time with a 4x4 finding a transfer case and all that.
A zf 5 tranny with an underdrive from Gear Vendors or US Gear would accomplish the same thing with less headache and probably cheaper. Also you could have a limited slip differential that you could not have with the 2 speed axle.
This would also leave out the overdrive that we all need with todays fuel prices.
Dollar for dollar I think the Zf 6 would be the best and cheapest route to get more lower gears and an overdrive with less fabrication of non existant parts.
