I want to install 4.10 gears in my 93 F150 with a slightly modified 5.0. I am told that if I don't replace the carrier? or housing? that it will destruct itsself in no time. what really would happen, if anything.

 

I've never heard that one before, people change gears all the time and they make kits to just change the gears and nothing else.

The important thing is to set the gears properly, most use shims and require that you set the backlash and other adjustments. The gears need to line up properly but you can tell by using a dial guage and marking grease where the gears are. Don't worry about changing the gears only, just make sure they are installed properly.

 

I agree but didnt know if the weight of my 150 flareside would affect reliability. Do you know if the 8.8 in my truck is any beefier than those in a Mustang 5.0?

 

The trucks use a 31-spline 8.8, the Mustangs use a 28-spline. The 31 spline axles are much bigger and stronger, the carrier is also slightly bigger, as are the spider gears. The ring and pinion, the carrier bearings, and the pinion bearings are the only parts that are the same between the 2 versions.

Do NOT even attempt this yourself without a Ford Shop Manual, which costs $85 or about 1/2 the cost of having someone do it for you. If you do decide to try it yourself, there is a setup trick that you can use changing the R&P on a previously (and properly) setup rear end which allows you to bypass getting a hold of Ford's very expensive ($900+) pinion depth gage.

When you get your old rear end apart, save ALL the pieces. The pinion, rear pinion bearing and pinion shim(s) come out as a pressed together assembly. Take it to a machine shop and have them press the bearing off and save the shim(s). It is CRITICAL that they do not destroy the bearing when removing it. Have the used bearing honed out to where it is a very tight slip fit on the pinion. Reassemble the used bearing and shim pack and used crush sleeve with your new pinion. Install the new ring, shim the carrier for backlash per the manual and check your pattern with the white marking grease. Because of the way Ford controls dimensions on the 8.8" rear, you should not have to re-shim the pinion, but because it is a slip fit you can if you have to.

When everything is in spec and the pattern is right, take it all back apart, throw away the used bearing and sleeve, press on the new bearing and do a final assembly again per the manual. Recheck backlash and remark your contact pattern. If everything is good, put the cover on and fill it with gear lube.

 

Thanks for the advice Strange Ranger. I planned on having a local performance shop do the job, but didn't want to spend an additional $600 for something I didnt need. Local prices for installation of ring and pinion is $450 to $500.