I have a '97 F150 and I'm changing the differential fluid this weekend.

Here is a picture of what I bought:

http://i189.photobucket.com/albums/z...0/IMG_0451.jpg


Just wondering if this stuff will work? I chose it, mainly because it says High Oil Resistance.

It also says it's designed for high torque load applications.

There are so many that look similar. Will it do the job good or should I return and get something better?

Thanks for all the help

 

it will work i use the blue stuff myself from the same company with no problems

 

You should use the specific stuff that Ford sells at the parts counter. There's a thread around here somewhere with a picture and part number.

 

That RTV will do just fine.If you have the 8.8 differential go to any parts store that sells Fel Pro gaskets and ask for gasket number RDS-55341.Use this gasket along with a minor amount of your RTV on either side of it.Install and torque the bolts to 30 ft. lbs. in a criss-cross manner.BTW,if it is L/S don't forget the friction modifier!

 

I agree 10000% !!!!

After multiple drips and leaks, I finally got this stuff and ended the issues:

https://www.f150online.com/forums/sh...d.php?t=276840

 

I just did my 9.75 rear end and used the "Ultra Black, HI-Temp, RTV Silicone Gasket Maker" stuff...

This is the 3rd or 4th time I've done it and I used the 'red' and 'blue' before, but I had leaks initially.... With the 'black', I've been good two times in a row on the first try, so...???

Anyway, this is just what I do when I need to do this... It's a PITA and really sucks!! But, I don't have any leaks afterwards..

After applying the sealer, I let it sit for about 15 minutes. Then I put it on and finger tighten the bolts, just until I see it spread out the sealer.

Then I let it sit overnight! Yeah, I know that sucks, but that's what I do..

Then I give the bolts a little 'snug' with a ratchet and then fill it up with lube... The 'snug' is still not very much... No where close to 30 ft/lbs!

Keep an eye on it for the next several days. So far, I have not had any leaks or had to re-tighten the bolts...

My mistake with the 'red' and 'blue' stuff initially was that I tightened the bolts too much and just oozed all the goo out.... Then, I added the lube about an hour later and it leaked.... Repeated with the same stuff, but waited longer and didn't tighten so much and had better results....

I've tried to find the gaskets that BlueOvalFitter has suggested (he even gave part # for the 9.75" a long time ago), but no one had them... Then I gave up looking...

Mitch

 

do i need to silicone both the cover and the differential? I won't be using a gasket.

 

You can do both if you want but make sure both surfaces are free of ANY oil or old RTV! I use brake cleaner on a rag to wipe both surfaces before putting everything back together.

 

Why would you put the stuff on both surfaces? Doesn't make any sense to me. I'd say just put a good bead on the cover and bolt it on???

Maybe not though...

 

Does it have to make sense to "you" for it to be ok?When I had my 97s differential rebuilt I watched the tech put RTV on both the cover and the differential! And,he does this for a living!

 

It really makes no difference which kind of RTV you use or which surface(s) you apply it to. Red, blue, black or gray will all work just fine. What's important is that both surfaces are completely clean and dry, and you let it cure for a while before refilling it with gear lube.

-Joe

 

That's not my understanding. I've been told by a professional tech that synthetic gear lube can eat certain types and leak, and if you have a LS, the friction modifier can eat it too.

 

That may or may not be the case, depending on the lube, depending on the friction modifier, and depending on the silicone used. As long as I've let it cure for a while before refilling, they've all worked well for me.

 

I just don't think putting sealant on both sides makes any sense. It seems messier, overkill, and also seems like an unneccesary extra step. That is my opinion. I didn't say that because it's my opinion, everyone has to agree. I do not pretend to know it all. That's why I started this thread.

Peace Out

 

BTW,opinions are like (donkey)holes;everyone has one!
You came here seeking advice,I gave you some.You don't have to take it.
I figured if a professional differential rebuild tech puts RTV on both sides,then why can't the everyday shadetree mechanic do it too?
I don't think I was being sarcastic;just because you don't agree with something doesn't mean everyone will agree with you.
If you leave this forum you will be leaving from a wrath of members with plenty of knowledge,including myself! You don't have to like me or agree with my replies; just ignore me!