I have a 97' F150 with a 4.2 V6 3.08 rear end manual tranny and I'm have a heck of a time pulling my boat up slick ramps. Adding to the problem is oversized tires (P255's). I am looking at changing my gear ratio and want to know everyones opinion on wether this can be done at home and what ratio to put in. My mechanical aptitude is high (I'm an aircraft mechanic) but I know I do not have some of the specialty tools needed to do the job and I've never done this particular job before.

How long will it take a novice to do this?

What tools are needed?

And, should I even attempt this?

Thanks for your help,

JAS

 

I'm in the process of changing out my 3:08 to a 3:73. Last night my buddy and I spent 6 hours, got the gears swapped out. Spent 2 hours so far tonight adjusting the gears, I think we're real close to what we need. Taking a break now suffering from sleep depravation. If I had lots of money, I pay someone to do it for me, if they were reputable. I don't have lots of money so I am doing it myself and saving 3 or 4 hundred $. It definetly goes better with two people, putting the dif case in and out with shims in place. It still remains to be seen what kind of job I will end up with. The tools aren't too specialized. You can probably find what you need at your work, dial indicator, torque wrench, a micrometer is nice to check the size of shims. Also, I got a bedrug with the money I saved! Good luck!

Jeff

 

Thanks Jeff, let me know how yours turns out. I spoke with the people at Reider Racing and they also recommended the 3.73. I think that's what I'll go with. They sell a set of "dummy" bearings that slide on and off by hand for adjusting the shims without having to press on and pull off your good bearings, would this have helped your set-up? Also, what part of the job did you need two people for?

Looking for the dough to get this done!

Jeff

 

p40whk;
I have a 98 F150 4.2 5-speed. I changed from 3.08 to 3.55 last June. You can search my thread "3.55 gears installed by myself". The job is something that can be done yourself if you prepare and learn before you open the diff. It is much easier if you use Ford Motorsport gears. They are manufactured to a certain size and tolerance and will install correctly in your differential as long as you use the same size shims as were originally in there. Check pattern and backlash of course. If you go with 3.73 gears, you will have a harder time correcting your speedo than if you go with 3.55's. This is because Ford only makes a 21 too gear for the speedo drive and you will need a 23. A 23 is available but they wear quickly. Do your homework. Post again if you have further questions. I could give you my phone number confidentially if you wish. GlennMc.

 

Just got back from the initial test drive. Everything seems OK! I got my gears at Reider Racing also and used the shim pkg. they sell. The install info they supply with their gears is good, after you have the differential apart. I have a 2001 Scab and couldn't find any books on it, I should have gotten the CD rom that is available, anyway, you should have no problem finding ford books for a 97'. One person can do it OK. Its nice to have moral support, and lifting the diferential assy. up into the case with the shims in place is nice to have extra hands. My buddy and I spent 13 hours doing the job, we just felt our way through it, not rushing. Glenn MC has good advice, not sure you can get 3:73 gears from ford for a 8.8 rear end. My speedometer is computer controlled so I have to have my superchip reburned, changing speedometer gears on the tranny is alot cheaper. We used the old pinion bearing to set the new shims, the instructions tell how to hone out the inside diameter to make it slip on and off easily. I think Reider Racing will give you good information. I have to wait and see if the job I did holds up, every little noise I hear will probably make my heart skip.

Jeff

 

Thanks for the info guys. Glen, I read your thread and you have a lot of great advice. Right now I am in the research mode so I will be gathering as much info as I can before I start. I hadn't even thought about the speedo issue. It's a bit of a relief to hear that your change went smoothly and that Reider Racing was helpful, they also seemed to have the best prices of all the shops I checked including Jegs and Summit. I tow my boat through the mountains of Tennessee on a regular basis so this is something I need to do. I hope I can contact you guys when I finally begin this project, thanks again for your help.

Jeff

 

Jeff, I forgot to ask if you saw a noticable difference in how your truck now performs? Let me know your before and after thoughts as to what the differences were and whether you thought it was worth it. Glenn MC said in his thread that it was like going from a V6 to a small V8, that would put a smile on my face.

Jeff

 

p40whk,
Just speaking from experiance, If you have the knowledge and tools to DYI then go for it.
One of the biggest (shall we call it FEARS) for me is not knowing if the shop you picked really knows what they are doing. I am a big-time DYI fan and will take time and energy in learning because I know I will do the best job for myself. I did not feel I had the tools or knowledge to do the rear change.
Also, check the web site for Randy's Ring and Pinion. They have a lot of good information on rear gear changes and some pritty good prices. Go through their articles and you will pick up a lot of advice on setting up the rear.
I am running a 23 tooth gear (speedometer) in my truck and so far no problems. If it does strip then no big deal, it is real easy to change.
Have fun, I can tell you I have never looked back and love the performance of my truck after the gear change.
If you need a 21 tooth speedo gear then send me an e-mail. I've got one in the garage I will never use and will sent it to you... Free (just hate to throw away good stuff).