Ordered 4.10's

03GTvert

New Member
Nov 2, 2003
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Well, I just ordered my FRPP 4.10 gear and I'm going to install it myself. I've read every how-to I can find and it doesn't really sound that hard if you have the proper tools. So I also bought a 1" dial indicator with a magnetic base, a dial caliper and a buddy of mine has the torque wrenches (I have the rest of the tools). I'm going to use Royal Purple and probably do my rear brakes while everything is off. My car has 60k miles on it now. Is there any last minute advice while I'm in there? I can hardly wait to join the gear club!
 
svttech76 said:
you will love the 4.10's they are the best mod under 500 bucks hands down..

BTW how do you plan on measuring the pinion depth.. ford a special tool for it if you can borrow this setup than that will be the best way too go

Exactly right, best mod I've done so far. Did em myself too. I didn't have any problems, but you have to have a press available to do the bearings and to get the old ring gear off. Throw the new ring gear in the oven for a little while and it should slide right on the diff. To do the pinion depth I used the MHD method for pinion depth. I have heard of a different way to do it is to use a straight edge across the bearing caps and using a depth mic or dial caliper to get the pinion depth. Don't expect this to be a quick mod. Plan on at least a full day to change the gears especially if this is the first time you've done it.

I have a writeup that someone sent me that I used to help me with the gear swap. If you want it I'll be glad to send it to you. PM me if you want it.
 
4.10 Q's...

This is for all you guys that already have 4.10's installed... How "streetable" are they? My pony is a DD with 90miles round trip about 3 or 4 times a week. How is the gas mileage affected. How do they handle around town in stop-n-go traffic? I have a Cobra T45 and 3.55's installed in a 98 GT, and although they are alot better than the stock 3.27's, I want more.

Thanks in advance,
DG079
 
Its not bad. You'll be in 4th around town alot. I'll do 2700-2800 RPM on the freeway. A little loud with O/R pipe, but I usually have stereo cranked anyway I may have lost 1-2 MPG on a tank average. Tho that could also be the fact I cant keep my foot out of it between the gears, motor mods and MGW shifter.
 
I too was going to measure the pinion depth using th e MHD method. Really the only thing I haven't resolved is a bearing seperater/puller. How hard is it to find one of these gems?
 
You dont need a press. We did the instal on my 3.73s...just use some cold chisles and pry it off. Does no damage, but takes about 20 minutes. We didnt even have to change any of the shims lol, just swapped the carrier spacers. PERFECT. We used an old trick...run a thin paper wrag through the gears (with a little grease on the gears). If the wrag gets cut then its too tight. If it comes out crinkled exactly like the gears but not cut then its perfect. If it comes out and is a little pressed, but doesnt look perfectly presses then its too loose. You can also feel what kinda slack it has. Feel what slack it has before you take the rearend apart and try to match that. then do the wrag thing.
thats for people who dont have those tools....we have done this in the following rearends.
1... 9inch
1... 8.8
3ish.. 8.0
and on my dads 7.5 rearend in his V6. It cut the wrag but we still put it in just to see since we forgot which spacer was which and the other way didnt seem to fit. It whined and we pretty much immediatly parked it....then my sister unknowingly took it for a drive :nonono:. We pulled it back down and swapped the spacers (worked that time lol) and its right now, but there is still a little whine...thats due to the pattern being worn in from the drive, but its very light now. All the others have ZERO whine and have very little slack.

BTW we learned this from a former funny car mechanic/drive that raced back in the 80s. Fortunatly we havnt had to swap the shims yet in the 7.5/8.8 rearends...otherwise it would be a PAIN since you have to beat the pinion gear in and out to change the shims. The 8 and 9 inches are FULLY adjustable by the turn of nobs on each side of the pumpkin :D.