Hello all thanks for any time you can give. New here and new to Diesels.Correct me if i'm wrong but my IHD 85 IDI is not known for daily runner/commuter? however it's necessary. Point is when traveling at 75, when I come to a hill mainly, but even a grade in the highway I loose considerable speed nor can I get back on the pedal resulting in any response since its floored.(Sunday drive Grandma should be driving it kinda response). Can't even keep up with with traffic. Also it has no power to speak of on the get up. Please any suggestions?  

i need to mention that from say 20 -50 mph it operates and I guess it runs good?  

How long have you noticed this problem? Is this recent, or has it always been like that? To be totally honest with you, that engine was never really considered a powerhouse, especially compared to the newer turbodiesel trucks. Probably your best bet (even though it'll cost a little money) is to try to find a Banks Sidewinder kit for it. That should help considerably. It's still not going to win any tractor pulls, but should give you enough extra power to get over the hills.

Is it smoking a lot on the uphill grades? If not, you may not be getting enough fuel. But without a turbo, any power gains you get are probably going to be minimal.  

Just bought the truck. So it's unknown. The guy I bought it off of thought the trans was bad and all I had to do was adjust the 2nd gear band adjustment screw. Got it for 500$ can't really go wrong it's a nice truck to boot.Please keep in mind this isn't just a lack of power and im not looking for anysignificant gains. However it would be nice to go down the highway without literaly being "in the way". also not really any smoke at any given time! Where would I find a sidewinder and what would I gain from it. Also does anyone have this 85 6.9 set up that wouldn't mind sending me a pic of the injection pump so I can compare the setup? As detailed as possible, or where can i view scamatics of this system?       THANKS ALL!!!!!!!  

I don't think Banks sells the old Sidewinder kits new, but I remember a few years ago they put one on, so they might still have a few on the shelf. I'd just search eBay or Craigslist for a second-hand kit. But probably wouldn't be a bad idea to have the tranny looked at first.  

ATS has specifically built a turbo for this engine, you might consider looking there, if you want to buy a turbo. If you do I would consider buying head studs for the 6.9l because you can risk blowing your head gaskets. There are studs out there that are made for that engine but I cant remember were I found them. Just something to think about.  

I have a Banks turbo setup for your truck, but since I've been running a 6.9 for years, and love 'em, I'd say that your "power" problem is in the transmission. I've routinely pulled over 20,000 pounds with an old 89 F-350 dually, 5-speed pickup without a turbo, from So Cal to the Canadian border, so I know what a 6.9 is capable of.

Without a doubt, the 6.9 is a whole new animal with a turbo, but if your truck is running fine, until you get to a hill, I'd say it's the C-6 transmission. On "level" roads, it's still slipping, but obviously it's just not as noticeable. Those C-6 transmissions shift via a mechanical speed  governor, and they're tough as nails. I like them 1000 times better, and they're MUCH tougher, than the E40D.

Did I mention that I have a great C-6 transmission WITH a Gear Vendors overdrive unit for sale?