Wailing highway RPM's!!
Freshman User
Joined: Jul 2006
Posts: 39
Likes: 0
From: California Central Coast
I just saw this thread now, I'm a little late but I wanted to comment anyway. I had 4:10's in my 87 f-250 at 65mph I was at 3000-3200rpm. I had a shop install 3:55's, parts and labor cost $820 (california?). I have never been able to get gear swaps quite right so I had a pro do it. Now at 65mph I run about 2600rpm. A decent improvement I guess however I really lost alot of torque, I used to be able to pull our local killer grade at 65mph no problem but now my truck struggles to climb the hill at 50-55mph (empty) on the floor. I have mixed feelings about the swap, I think it depends on what your after, I did get better mpg on the flats and I guess less wear on the engine but sacrificed other things.
Lead Driver
Joined: Nov 2003
Posts: 6,900
Likes: 3
From: Campbell River, B.C.
Originally Posted by Bioford
I just saw this thread now, I'm a little late but I wanted to comment anyway. I had 4:10's in my 87 f-250 at 65mph I was at 3000-3200rpm. I had a shop install 3:55's, parts and labor cost $820 (california?). I have never been able to get gear swaps quite right so I had a pro do it. Now at 65mph I run about 2600rpm. A decent improvement I guess however I really lost alot of torque, I used to be able to pull our local killer grade at 65mph no problem but now my truck struggles to climb the hill at 50-55mph (empty) on the floor. I have mixed feelings about the swap, I think it depends on what your after, I did get better mpg on the flats and I guess less wear on the engine but sacrificed other things.
Thread Starter
|
Junior User
Joined: Nov 2006
Posts: 61
Likes: 0
Well, not sure where to go at this point; sounds expensive considering we've got a 4X4, double the 800.00 or so cost? It just sounds like the 7.3 non turbo just doesn't produce enough torque or ponies to go to a higher gear ratio. On our Anchorage trips, there are a number of big hills, even our Bronco with highway gears (rebuilt v-8, 4 bbl. carb, etc) has a hard time holding 65 mph on those hills. I think I'll just get the tallest, narrow tires I can get to fit without rubbing on the truck, as it's about ready for new tires; plus the fact that we only drive this truck a few months out of the year makes spending money seems foolish.
Thanks,
Jim
Thanks,
Jim
Lead Driver
Joined: Nov 2003
Posts: 6,900
Likes: 3
From: Campbell River, B.C.
You could keep an eye out for a GV overdrive, from what I have heard they are pretty hard to find second hand, but you never know....
I think it would give you a final drive ratio equivalent to 320:0, and you would loose no drivability either.
Ring&Pinion sets are way cheaper than $800, and I have seen second hand sets for as little as $100CAD locally, but that assumes you put it in yourself.
I'm not sure, but I think the best tires you can get for fuel economy are the stock 235/85/16, they are also nice and narrow.
I think it would give you a final drive ratio equivalent to 320:0, and you would loose no drivability either.
Ring&Pinion sets are way cheaper than $800, and I have seen second hand sets for as little as $100CAD locally, but that assumes you put it in yourself.
I'm not sure, but I think the best tires you can get for fuel economy are the stock 235/85/16, they are also nice and narrow.
Freshman User
Joined: Jul 2007
Posts: 42
Likes: 0
From: Ohio
My truck also had 4.10s when I got it and I swapped to 3.08s. The gear change was not hard at all and I had no prior experience with R&P swaps. I got my set new off the web (sterlings are not avalable from factory with 3.08s) and it cost about $USD225 and worked out to $CAD400 delivered to my door. That was almost 40k miles ago, so it has definately paid for itself by now.
A gear change is the best bang for your buck IMO.
A gear change is the best bang for your buck IMO.
Lead Driver
Joined: Nov 2003
Posts: 6,900
Likes: 3
From: Campbell River, B.C.
I used a torque wrench to torque the internal bolts to speck. I used a 16" breaker bar to torque the pinion nut. I used a micrometer to check the size of the crush sleve. Thats it. Theres not big deal to a R&P swap, at least not with this differential.
The only thing I would have done differently is to get a solid spacer to replcace the crush sleve as it would have saved me some hassle.
To be honest, I'm still trying to figure out what the big deal is that eveyone is talking about when it comes to swapping gears.
As an update, The E4OD tranny is in now and the truck is just a little scary to drive now once its on the freeway. But if I set the cruise at 70 MPH, it will consistently return 20 MPG for an average. Even the slightest tail wind can push it toward the mid 20s (empty truck).
The only thing I would have done differently is to get a solid spacer to replcace the crush sleve as it would have saved me some hassle.
To be honest, I'm still trying to figure out what the big deal is that eveyone is talking about when it comes to swapping gears.
As an update, The E4OD tranny is in now and the truck is just a little scary to drive now once its on the freeway. But if I set the cruise at 70 MPH, it will consistently return 20 MPG for an average. Even the slightest tail wind can push it toward the mid 20s (empty truck).
Thread
Thread Starter
Forum
Replies
Last Post
instantlegg
1978 - 1996 Big Bronco
5
Dec 24, 2010 02:42 AM
mechelement
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
64
Feb 19, 2010 06:08 PM
wrench jr.
1967 - 1972 F-100 & Larger F-Series Trucks
5
Mar 31, 2009 11:36 PM
viperbluelx
1999 - 2003 7.3L Power Stroke Diesel
17
Oct 3, 2007 05:28 AM
