Hey buddy!

 

I agree on all counts. I had 1 4.10 truck, 89 250 C6 351 sounded like it wanted to blow up at 60-65. But that truck could pull a house down.

Im sure the OD helps with that. My only concern is DD capabilities. I need to sleep on all of this information, make a decision, and go with it.

 

I think with the 285s, and auto trans, even the daily driving would improve. Again, just my opinion.

 

My truck must be the exception lol. No matter the trailer I pull, if I revv past 2000 rpm, it feels like Im going no where. Therefore, when Im in the OBS, I keep it right at or near 2000 rpm at all times.

Mind you, I am also sporting the 4.10 gears. I used to absolutely hate 4.10s, escpecially when I was daily driving it. After pulling some trailers, Iv learned to appreciate the 4.10s.

Would I put 4.10s in the Excursion? Hell no! All it does is drive down the road and occasionally pull my car trailer. Would I put 3.55s in my OBS? Hell no! Its a work HORSE! Mind you (and I know Iv told this story before) the ONLY time my OBS has seen 3rd gear pulling a loaded trailer was on Black Mountain - a 6% grade for 6 miles. The biggest hill we saw at RRE IIRC was a 4% grade for 2 miles.

I dunno Thomas... its a double edged sword. Your mpgs are gonna suck unloaded on the highway with the 4.10s but itll pull like a mule. And vise-versa with 3.55s... After swapping from my pizza cutters to 285s, I havent seen anything over 15

 

Good Luck Thomas, this is a tough one. Even though thru the years I have done lots of mods its terrible that one little gauge tells you how hard you can push it!

 

I think people worry too much about the mileage thing/ commuting ability with the 4.10's.

Mine rev's a little high on the freeway but my mileage doesnt really suffer. I routinely hand calculate 15-16 with my 315/75-16's. My odometer isn't corrected for increased tire size either so it actually slightly better than that. What the 4.10's do is put me deep in my power band for all the passing power I could want at freeway speeds.

 

Matador, My camper, 31' Nomad "Skyline". Weighs 7800 lbs dry.
My truck is completely stock w/6638 as well. I posted up some questions earlier this year about towing mine. The roads are pretty flat here on L.I. but i always pulled it out on the beach, NP. Acceleration was an issue but she got the job done........... never got hot. I've got 3.55's as well. Don't forget that your losing some gear with the big tires also. Sure, there may be something wrong but prolly not major. With a stock truck and no EGT gauge, who knows how hot mine gets. Sometimes knowing all that stuff is as rewarding as knowing how many guys your girl had before you. If you're on stock sticks and turbo, I don't think EGT's would get to the danger zone. Oh, and BTW..... I know its behind me, not very aerodynamic. Rarely use overdrive and tow around 60 mph. Don't lose your head, you'll get it right with these guys here. Mine has 300,000 k roughly. I'm towing out to Kentucky through the mountains of West Virginia next year. I'm not rich.....I'm gonna pull it with my stock truck. Regards , Vinny

 

Also.there is a reason ALL duallies at the minimum came 4.10 ratio Lil

Will it fix it? Who knows ...it sure will help I know that.

 

Thomas, I'm not saying that switching to 4.10s won't help. If you want to tow with the truck, 4.10s will do a better job of that, undoubtedly. What you will sacrifice is fuel economy when unloaded. It's a trade you have to be willing to live with. I've had both in these truck and they both have their merits. 4.10s definitely give you more power in every gear, and that's what you want for towing, but 3.55s definitely give the truck longer legs for highway driving. If I ever get to the point (like a lot of these guys are) of using my truck primarily for towing big loads, I will likely be looking for 4.10 gears (or.. maybe SD axles with 3.73s), right now that's just not how I use it, so I'm happy with the gears I have.

If you're in the position of needing to do something with your rear axle anyway, and the D60 you have is a 4.10, then I think you have a pretty convincing case for making the swap. You can probably go to a JY and pull a 10.25 with 4.10s in it for less than half the price of having new gears installed into your existing housing, then sell the axle you have now and recoup almost all of your cost (maybe more if you get a good deal at the JY). Plus then you save yourself all the hassle and expense of having the gears set up. An axle swap like that is doable in a day if you have everything lined up ahead of time. Just food for thought...

 

Well, I guess this is the clincher then.




I happen to have a truck I'm parting out with you guessed it, 4.10. I think it's open though. Its an 88 f-350. Bill seemed to think it should work. The axle won't obviously because it's a cab and chassis, but the guts will!

 

You'll have to pay someone to set it up for you if you go that route (unless you're inclined to do it yourself). Honestly, I would just sell that dually rear and buy a SRW axle if it were me and then swap the whole ball of wax. If you decide to swap that is...

 

I would be definatly paying for set up. I would have no clue where to begin. Like you say this is "if" I swap.

I'm not sure what to do. Its one of those deals where you know you have to do something, but how you want to go about it is stopping you up.

 

If it were me, I'd make sure I had the engine running tip-top before I changed gears. Then if I am still not satisfied, I'd switch gears or make more power.

 

Agreed. If you're seeing excessive EGTs even in 3rd while you're spinning 2500-2600 RPM, then the gears aren't the solution, because they aren't the issue.

I'd test compression and for boost leaks and if you don't come up with anything there, then I would pull the chip and try it out on the stock PCM before I'd send the injectors to Jim.

Like I said, I am running stock injectors and canned TS tunes and I can get the EGTs up there too, even with the 6.0 IC I have in there. I'm still not completely satisfied that I'm not leaking a little boost somewhere, but I can push the upper teens with the chip turned up, so I can't be leaking much if I am. I have tested the system 2 or 3 times and can't find anything so I don't know what else to blame it on except the tunes. I can't get it hot enough that I have to back out of it, but it will flirt with 1200 degrees if I stay in it. I don't know that I have tried it in the stock tune. I may have to give that a shot next time out. Ultimately, I'm in somewhat the same boat as you are, debating about how much to do and how far to go with it. I think I'll go stage 1's eventually, but that's pending funds as well, and I know I'll probably have to address the HPOP after I do it. Then the turbo will be more or less at its limit, so I suppose at some point that may need to be addressed as well. It's a vicious cycle...

 

This seems like the best way to tackle this problem.