Well,

Two reasons for the post: first being to review the difference in the way my trucks performs going from a stock 3.55 LS to an aftermarket 4.1 LS Ford Racing Ring and Pinion, and secondly to address a leaking problem with my differential.

For the review... I finally got to hit the backroads to my girlfriend's house that I've raced up many times before- keyword being UP. It's a fantastic backroad that goes UP a constant, fairly steep and windy backroad...a real pain when your truck likes to downshift constantly due to the need to slow down for the turns.

Now that I have the 4.1 ratio I was able to BLAST up the backroad with significantly less downshifting, more solid power throughout. I love the feel of the switch to the 4.1, and highly recommend the change. Also, I did change my stock 18s with 265/6018s to 22s with 305/40/22s...which are 7% taller, and a couple inches wider. Even still the 4.1 makes the truck very formidable off of the line with only exhaust and intake.

As for the MPG change, I haven't gotten the math exact yet due to all the changes in ratio and tire size, but I am fairly certain with me doing mostly city driving it hasn't changed much. I do get better milage on the freeway than the city however.



NOW FOR MY PROBLEM, which I would REALLY appreciate some help on. I have had to go back THREE times to have my rear differential re-sealed due to a leak. I keep finding small puddles of the light green fluid dripping off of the bottom of my rear differential. I just got it back, and yet again it has a slow drip. IS there anything I can check.try before going back yet again? Is there a specific amount of pressure ( I have a torque wrench) that the bolts should be at? I can maybe check that...

 

They're probably not allowing enough time for the sealant to cure before refilling and/or not ding it properly.

If you want to do it yourself, here's my method and it's always worked for me.

Pop the cover and drain it all out. Clean both surfaces thoroughly with brake cleaner to remove any residue of the old sealant. Then, apply a thin bead of silicone to the cover around both sides of each hole. Install the cover using a criss-cross pattern to tighten the bolts to the appropriate torque, and do it in stages so that the cover doesn't warp. Then, (and this is the most important part IMHO) Wait at least 3-4 hours for the silicone to cure before refilling with gear oil.

I've done it a half-dozen different ways and had it leak. This is the only way I've done it and consistently NOT had a leak the next week.

-Joe

 

If it is leaking from the surface around the cover it could be 1 of 3 things. The mating of the surface of the housing is not flat, the cover itself is warped or they are not allowing enough time for the sealer to set up before filling the differential and it leaks. If it is leaking from somewhere else it could be porosity in the casting. A cracked weld where the tubes attach to the housing or a cracked housing.

 

That's what I meant to say LOL!

No, I was just assuming that he was talking about a cover leak, but what JMC said rings true.

-Joe

 

I really appreciate both of your replies.

By chance, so I can go check it...do either of you know approx how many ft ls of pressure should be on the bolts? I am hoping it is a simple fix like that, but who knows.

 

I spoke with a few guys that said I could probably just use some high-temp silicone (exactly what they use inside the differential) on the OUTSIDE of the differential without opening it and it should work.

Anyone know if that makes sense?

 

I wont work if it is already leaking. The diff fluid will dilute the silicone and stop it from adhearing to the metal and it will eventually leak. Pull it apart and do it over again.

JMC