I have the 4.2l f-150 and 3.55 gears, and got 33in tires put on there. I looked into getting 4.10 gears. Is it more viable to spend the 650 elsewhere on a chip and exaust or is it worth it?

------------------
1999 4.2l 2wd super cab F-150. Mods: 3in body lift and 285/75 R16 BFG AT 3.55 gear 10 disk changer

 

ilmagill,

Spend the $$ and get the 4.10's. That price seems a little high, I paid about $560.00 or so for the gears, new bearings, and installation. Don't nickel and dime yourself on other mods UNTIL you get the new gears. Your only fooling your self. Lower gears (4.10's) are THE MOST BASIC mod you can do to your truck to regain lost power due to the bigger tires. I see and hear so many folks out there doing the *wrong" kinds of mods to improve lost power. I went throught he same ~pain~ ($$) as you are thinking right now. But once you hand over the money and (break in the gears PROPERLY) you will forget about the $$ you spent and will love driving your truck. Well I am over it now and I am dam happy w/ my gears. Since then I have added the Superchip. Life is even better :-) If you can dish out the $$ for a quality set of gears then do it and be done w/ it. I can guarantee you one thing, you WILL NOT be disappointed w/ the 4.10's. I had the stock 235's and went up 3 tires sizes to the 265's. I noticed a big power loss off the line and passing on the HWY was a joke. Upgrading 1 or 2 tires sizes may not warrent new gears, but I would highly recommend them if going any taller.

BTW what size tires were you running before the 33's?

F&B's

PS read dirtslingers comments. We recently met up and I took him out for a spin in my truck. https://www.f150online.com/f150board...ML/000306.html

More comments from me here; https://www.f150online.com/f150board...ML/000281.html


------------------
98 F-150 XLT, SC, SWB, 2WD, 4.2L auto, 4.10 gears w/ LS, Tow Pkg. BFG AT 265/75/16, K&N air filter, Dynomax muffler, Superchip, Edlelbrock shocks, Hellwig sway bar, 3" body lift, signal mirrors...tons of cosmetic products




[This message has been edited by franks&beans (edited 01-25-2000).]

 

I had 255x70x16 generals. What exactly do you mean by breaking them in? Thanx for the reply.

------------------
1999 4.2l 2wd super cab F-150. Mods: 3in body lift and 285/75 R16 BFG AT 3.55 gear 10 disk changer

 

ilmagill,

>>What exactly do you mean by breaking them in?

What I mean is the gears are new and haven't been mated yet, The ends of the gears that came out of my truck were smooth, shiney like chrome and were properly "seated". The ends of a new set of gears are not shiney, and have a coating on them from the factory. This coating will wear off then the gears are meshing toghther, This meshing will create that shiney chrome like smooth surface. If you were to drive off w/ the new gears and do burn outs, squeeling tires, and really putting a load on the axel(s) you would heat up the those new gears so fast the oil wouldn't have a change to cool them down fast enough, it would actually burn the oil that was running between the gears, thus breaking down the physcial protective properties of the oil. The gears will heat up to a point that it would weaken the metal, discolor the gear tips and shorten the life of the gears. Ring and Pinion gears will out last a truck, if properly broken in. Remember, these gears are new, and not properly mated yet, there is a "TON" of friction (which produces heat) created between the meshing gears. (you can ruin a set of new gears in a matter of miles if you don't let them wear away that "rough coating" and seat properly, towing is out of the question for at least 100 miles the load would surely toast them) The shop who installed mine took it out for a test drive, they came back in a about 10 minutes and the tech immediately took the temp. reading off the differential cover w/ a laser looking gun, it reads the heat buildup on the differentail cover caused by the gear break in and the oil. He told me one time this guy blew his advice off and took off, they got a call a while later, this guy was wondering why his differential was so hot you wouldn't touch it! When I left the shop the tech asked me how far I lived from the here, I said about 15 miles, he said do not drive any more than that. Let it cool down completely, then drive it again for another 13 to 15 miles and cool again. Then he said it would be ok to drive it a little harder, but no towing for another 80 or so miles. This is like telling a little boy w/ a new remote control race car not to go fast. It was hard for me to hold myself back (not because I am a crazy nut driver, But rather I was exceited and wanted to "test" them out. It's hard to do BUT it's essential to follow the break-in proceedure. Think of new gears like your new engine, you wouldn't drive it off the dealer lot w/ your right foot planted to the floor. and revving the sh*t out of it.

Hope this helps, sorry for rambling on.

F&B's

------------------
98 F-150 XLT, SC, SWB, 2WD, Pac. Grn., 4.2L auto, 4.10 gears w/ LS, Tow Pkg., BFG AT's 265/75/16, K&N air filter, Dynomax muffler, Superchip, Edelbrock shocks, Hellwig sway bar, 3" body lift, signal mirrors, ...tons of cosmetic products



[This message has been edited by franks&beans (edited 01-26-2000).]

 

I just wanted to reinforce a few points that F&B made. I have driven trucks with high gears and oversize tires for years. Finally on my third F-150 I decided to go for it, and get lower gears. It was worth every penny! If you're running oversize tires, the gears should be the first performance mod you make. All the HP in the world isn't gonna help if you're running too tall gears.
Also, it is VERY hard to break in a new set of gears properly. I must confess that I have been pretty hard on mine even though I have been forwarned. It's so hard to baby the truck when you know all that extra performance is there.

Go for it!

 

New gear break-in proceedures

Just like I said and rockcraw just posted, throttle back when you get the new gears until they are broken in. read on

Quoted from ring-pinion.com

New Gear Break-In
"Do we really need to break-in a new gear set? I have heard many people say "When I bought my new truck no one ever told me to break-in the ring & pinion." Whenever we are blessed enough to afford a new vehicle, we take it easy on the engine for the first few hundred miles. While we are pampering the engine (probably for the last time ever), the ring & pinion set goes along for the ride and gets a chance to break in before we hammer the throttle.

In most stock vehicles with stock tires there is seldom a risk of a burned gear set. For those of us who modify and use our trucks, there many situations that can contribute to burned gear syndrome. Motorhomes, towing, tall tires, and high numeric gear ratios (4.56 & up) can all generate a lot of heat and cause the gear oil to break down. The greatest damage to a new gear set results when it has been run for ten minutes or more during the first 500 miles and the oil is very hot. Any heavy use or overloading while the oil is extremely hot will cause it to break down and allow irreversible damage to the ring & pinion.

In order to make them run cooler and quieter, new gears are lapped at the factory. However, they are not lapped under the same pressures that driving creates. The loads generated while driving, force any microscopic high spots on the gear teeth back into the surface of the metal. This is called "work hardening". Work hardening is similar to forging in the way that it compresses the metal molecules into a very compact and hard formation. This can only be accomplished if the metal surfaces are lubricated and the gear temperature stays cool enough that the molecular structure does not change. If the temperature of the metal gets hot enough to change the molecular structure, it will soften the surface instead of hardening it. This may seen like a balancing act but it all happens easily & passively as long as the oil keeps the gear cool while it is breaking in. Some of the synthetic oils on the market today can help a gear set live longer. I've had great success with Red Line ®, Torco ®, and Richmond Gear ® synthetic gear oils. These oils will continue to lubricate at temperatures where many crude oils break down.

Even with synthetic oils, I still recommend the following procedure for breaking in a new gear set: After driving the first 15 to 20 miles it is best to stop and let the differential cool before proceeding. Keep the vehicle at speeds below 60 mph for the first 100 miles. I also recommend putting at least 500 miles on the new gear set before heavy use or towing. During the first 45 miles of towing it helps to go about 15 miles at a time before stopping to let the differential cool for 15 minutes before continuing. This is necessary because not all of the gear tooth is making contact until it is heavily loaded. When towing, the teeth flex to contact completely, and cause the previously unloaded portion of the teeth to touch and work harden. All of this may seem like paranoia, but it is very easy to damage the ring & pinion by overloading before the teeth are broken in. If you take it easy on a new ring & pinion and keep it full of high quality oil, it should last a lot longer.

With regards to limited slip additives, I have found that using too much additive can lead to premature gear wear. Use just enough to keep the limited slip from chattering but not more than 4 oz for every 2 qts of oil. It is a good idea to change the gear oil after the first 500 miles in order to remove any metal particles or phosphorus coating that has come from the new gear set. This is cheap insurance and a good time to discover any problems before they grow to disastrous proportions."


------------------
98 F-150 XLT, SC, SWB, 2WD, Pac. Grn., 4.2L auto, 4.10 gears w/ LS, Tow Pkg., BFG AT's 265/75/16, K&N air filter, Dynomax muffler, Superchip, Edelbrock shocks, Hellwig sway bar, 3" body lift, signal mirrors, ...tons of cosmetic products



[This message has been edited by franks&beans (edited 01-28-2000).]

 

Also, since this is the correct way compensate for larger tires you save $$$ not having to recalibrate the speedometer.
Your revs per mile is back to the way it was before the larger tires.