Good morning! I'm brand spankin' new here. I don't speak mechanic, nor do I claim to be one. I can change my oil (I think), check the air filter and change the wiper blades. Anything else, and I'm in deep doo doo.
BUT, when in doubt - ask the experts! That's why I'm here.
I own a '97 PSD HD F-250 XL. Manual. 4x4. 3.55 axle. 127K miles. It's our farm truck. Not pretty, but a good runner. GVWR 8800 lbs. Last weight at the scale (Driver & fuel) 6400 lbs. I don't have the chart, but my guess is the GCWR is 15,500 lbs.
We bought a 28 ft 5th wheel (acutally measures 32ft). Dry weight about 8600 lbs, GTWR 10,600 lbs. I don't know what the pin weight is.
On our maiden voyage, it appears we need to make some adjustments for better towing. We've got lots of hills and passes here in the PacNW. Heading up hill, we may start at a good speed, but we're down to 30 mph at the top. When down shifting and the truck is under load (on the hills) we get a funky vibration which will stop when the clutch is in. Other F-250's (2500's) with similar trailers were leaving us in the dust.
I've done a ton of research on this topic, and asked some questions in other forums, but all this mechanical talk has encouraged me to do more research. FYI - there's a great web site out there (http://www.howstuffworks.com) which does a really good job explaining how transmissions, differentials, gears, torque converters and more work. It has a lot of good illustrations and moving images for the mechanically challenged (Like myself).
Now, my questions relate to these things and towing.
1) Gear ratios - the 4.10 is always listed as "better for towing, but worse for gas mileage." Now, if you have the 3.73 or 3.55 gears, what is the effect when towing? Slower up grade? More wear/stress on what???
2) Diffentials - Limited Slip vs. open. What effects do you notice when towing?
3) Transmissions - When operating a manual vs. automatic, when towing, which combinations (with gear ratios/differentials) are ideal?

Lots of questions. Of course if you have any input I'm all ears. We're debating between what to do with this current truck vs. purchasing a different one (a new one really isn't in the budget, but I don't want to throw good money out the window on this one if it doesn't make sense) I thank you in advance for your help!!

 

Sorry I'm not a mechanic. All I can advise you on is my experiences. First your pin weight will be approximately 25% of you 5th. Looks like 2650 lbs. Your weights show 2400 capacity from the scale house. Not sure if that has something to do with the vibration that you are getting. There is alot of debates between the F250 and F350 on CVWR with 5th er. I dont want to go there. As for the 4:10 I have 3:73 on my truck and get 16-17 highway and 12-13 towing. My co worker has a dully with 4:10 and gets about the same. I have a newer truck (6.0) so I dont notice the lack of power towing 10% grades with 7K on the rear. We will see if it gets that way when it hits 100,000. I also have a limitied slip and notice no difference. Sorry I cant give any input on the tranny question. I have an auto.

Hope this starts this thread for you. You'll get some good imput here from those that are will knowledgable. Good Luck.

 

Welcome to FTE and thanks for joining us in the Towing forum!
Congratulations on your new trailer purchase.

Well I believe you've experienced the troubles of too low an axle ratio during your slow uphill climbs. As long as you are towing within the rated capacity of the vehicle, it's more inconvienent than anything.
You won't notice any difference on clean, dry pavement. It only comes into play with loss of traction. Then LS is prefered.
Automatic vs manual is mostly personal preference. Each has it's own advantage. Again the ideal transmission/axle ratio will depend on what you intend to tow. It's always a compromise. But OD transmissions allow higher axle ratios without compromising too much on fuel milage.

 

Thank you all! If I'm understanding this right....
The lower the axle ratio, the less "oomph" I have to get up that grade. I have to pack lots of patience going up hill. If I'm within my truck's towing capacity, I'm not hurting the truck any. What will wear out first if towing with the lower ratio?
Limited Slip will be better when traction becomes an issue. (like for mountain passes in the winter?) When towing a big 5th wheel, is the limited slip going to help me any?
Manual vs. auto.....one guy told us that the rear ratio isn't a big deal with a manual transmission. Not sure I understand why? Anyone have some clarification on this one?
Again, many, many thanks!

 

Sure, the clarification for that is that the guy didn't know what he was talking about. Gear ratio is just as important on a manual as it is on an auto.

 

My last two V10's were 3:73 and 4.10. I did notice better "oomph" with the 4.10.

 

I swapped from 3:55 to 4:10 gears, definitely gave more grunt for towing. I even get better mileage in city driving.

Could the vibration be clutch chatter? How old is the clutch?

 

Thanks to all the help from folks like you - we agree that the vibration is likely from the clutch (Possibly slipping) or the U Joints. We've got an appointment to have someone look at it.
We've looking in to having the gears upgraded. Looks like about $2000 with parts & labor. I think that would be money better spent on the 1 ton.
Quick side note - saw an F-250 pulling a good-size 5th wheel disabled on a large hill this morning.....think it's a sign?? :-)

 

Minimum equipment recommended for rated capacity is just that, minimal. Clutch and U-joints are probably the weakest link in the drive train.
I was thinking more like off the pavement, but you're right, LS would help on snow or ice slickened pavement.
I disagree. If anything, it's even a bigger deal with a manual trans. With an automatic it's easier for the torque converter to overcome the lower gearing from a standstill. For that reason, the manufacturer's will say that you can go to a lower numeric axle ratio with an automatic transmission. But then you will get diminished towing and hill climbing ability. IMHO, you should pick the same axle ratio for towing heavy loads with either transmission.
Hey, if you need more ammunition to talk the Mrs. into an F-350, then yes, yes, yes!

 

Wonder if someone has an owners manual which has the towing capacity of the truck? I think you are at the max with the manual transmission.

 

When was the last time you changed the fuel and air filter?

re:vibration
Make sure all the fluid levels are up there and all the bolts for the engine/transmission/transfer case are there and tight. Before I messed with the clutch I would change the transmission fluid and flush the clutch system and bleed it.