Gearing and axle questions

[aaronbtxnc]

My truck is a 88 4.0 4x4 standard transmission, so assuming (I'll check before doing anything) it's still original I have the D35 with 3.07 gearing front and back. I have a parts truck that is automatic trans 4.0 4x4, and again assuming it's still stock the gearing in it is 3.55, right? Do I want to switch these out? I know I'd have to do front and rear. Would I have to swith any other parts out or just the "gear boxes". I'm pretty new to all this gear stuff obviously.

 

What are the advantages/disadvantages either way, especially regarding mileage?

 

Truck is primarily used for hauling firewood, mowers, mulch, helping friends move, etc. but will be counted on for delivering pizzas in the snow (albeit we don't get a lot around here, maybe 3 good snows a year). I want it to go anywhere I want to go in the snow. It will never be used for rock crawling/climbing, may see the occasional muddy back road with hills.

 

I'm running 235-75-15's.

 

If I'm looking to have to down shift less going up hills and get better mileage am I asking for the impossible?

[Pete M]

I wouldn't even think about swapping the gears, but rather would swap the complete axles themselves. gears aren't as easy as bolting them in. they must be set up properly and, long story short, it's just not for the novice.

 

3.55s should give you more perceived power (and a bigger smile) and a bit better fuel economy (since the engine won't have to work as hard to get the truck going from a stop). :thumbsup:

 

 

I'd do it in a heartbeat. :yes:

[aaronbtxnc]

OK, I just did a search for axel swap and couldn't find anything useful to me, well went back and searched axle swap and am wading through the results for a guide. How exactly do I go about this? I have done brakes before and tinkered quite a bit on an old VW (removed and replaced engine among many other things) but have never tried to remove an axle. Is this something a pretty green shadetree mechanic can handle (I can follow detailed instructions, just can't find them) or should I pay someone who really knows what they're doing or anyone in Western NC wanna come walk me through it for some beers :cheers: and gas money? I have a Hayne's manual at home, would this be covered in that? How many shop hours would this run at a Jeep friendly and knowledgable garage? If I go the garage route I guess I'd have to get both trucks there unless I could at least pull the donor's parts myself, and hell, if I can unbolt it I can rebolt it onto the other I guess, I really don't wanna have to rent that danged tow dolly again, although to the garage is mostly downhill rather than the mostly uphill I drug it home.

 

Thanks yet again guys!

[Globex]

In our shop we charge $100 to swap a rear axle in if it is a bolt in. Front axle we charge a little more due to steering linkage. Setting up a set of gears is right around $300 per axle. It's really easy to do. Take the weight off the truck and unbolt the brake line, u bolts, shocks and drive shaft. Roll the old axle out and roll the new one in and bolt it all in. On a lift I do it in way under a hour.

[foreman1063]

Take the weight off the truck and unbolt the brake line, u bolts.

 

Or control arms and track bar in the case of the front 30.

[The_Beave]

had to swap the rear out of my wifes xj last spring, she had the 35 with 3.07 and a manual trans too. wow what a difference when i went to an 8.25 with 3.55 gears. i can go up provo canyon, a decent mountain pass here in ut, in 5 th gear. + now i get 20 or better mpg. now i just need a front with 3.55 so she can use 4wd again. go with the upgrade, you will like it!