More Power for 4.0?

[rockhardzj]

I just so happen to have a D35 gear set for sale, and possibly a 30 set as well for 3.55's.

[Pete M]

Regearing an axle is not simply a bolt-in procedure and is either expensive (to have a shop do it) or tricky (not recommended for beginners). For his situation, I think finding an axle with 3.55s already inside would be the best bet. Careful searching should produce a 3.55 geared Dana 35 for anywhere from $100 down to totally free. Bonus if it's an MJ axle, but it's not hard to get new perches burned onto an XJ/YJ/TJ/ZJ rear axle. You can even use the brakes you have now (or use the new axle's, whichever are better). Then bolt it up 'n' go like the wind.

[MJCanadian]

hmmm, how will I tell if the D35 I find will have 3.55? I got a 90amp MIG so putting on new perches shouldn't to difficult. But yah never opened up a diff except to change the fluid before so for my interests I guess I'd stay away from regearing. Axel swap doesn't seen like that bad of a choice either.... + I have acess to a hoist and all equipment at my school. What about Axle width? are all D35's the same?

[DirtyComanche]

Dana axles are easy. Normally there's a tag on the cover, it's say something random but have clearly a 3 55, 3 07, 4 10, or something on it. If the tag cover is missing, or you aren't sure, pull the cover off. On the ring gear there will be two numbers stamped 41:10 or 41 10, or something, dividing them will give the gear ratio (in that case, 4.10). And occasionally they will even say somehting like '3.55' on them.

[FxRacing282]

well if its th stock axle and people havent played with it there should be a tag on the pumpkin that says the gears and if not then put the axle in the air and the t-case in N and then make a line from your d-shaft to your pumpkin and roate the driveshaft 360. if the tire rotated 3 times then you have 3.07's

[SoloCamo]

4.0L + stick = 3.07 gears. There's your problem. No need for expensive engine mods here. Go get a 3.55 geared rear axle (a dana 35 will work fine in this application) and drop it in. Your truck will come ALIVE with performance!!! I promise. :D

 

Only problem I see with that is that the Peugeot transmission isn't exactly intended for performance. ;)

 

I know I was a little too rough on it a month or so before it got totaled by a drunk, and it was making all kinds of whining :cry: Then again, with over 190k on the clock, I'm surprised it didn't do that earlier.

[HOrnbrod]

hmmm, how will I tell if the D35 I find will have 3.55? I got a 90amp MIG so putting on new perches shouldn't to difficult. But yah never opened up a diff except to change the fluid before so for my interests I guess I'd stay away from regearing. Axel swap doesn't seen like that bad of a choice either.... + I have acess to a hoist and all equipment at my school. What about Axle width? are all D35's the same?

 

If you have a 5-speed and nobody has messed with it, chances are you have 3.07 gears. Auto tranny gears were a higher numerical ratio (usually 3.55) to compensate for the AW4 OD. I had converted my D35 to disk brakes, and swapping out the rear end was not an option since I had some $$ into the rear end. I went from 3.55 to 4.11 because of the bigger tires, and it was my first time to regear a D35, although I had done various Ford rear ends way back when. Biggest problem I had was getting the pinion preload correct, then eliminating a slight binding high spot when installing the ring gear. Ended up using the exact same shims (after 3-4 tries) that the original 3.55 gears had on both the pinion and ring. The ones that came with the new master kit (Yukon) were all too thick. Also changed out all the bearings. Not too bad a job, especially if you have access to a lift. Daymed if i'd do it on my back. Got about 3K miles on it now - no problems.

[MJCanadian]

right now if i'm in fifth doin 120 (Km/h :Canadaflag: :D ) on the highway It revs at like 2000... and thats just bareable with the "muffler" i'm running and I have to keep gas mileage in the equation. So if I were to switch to a 3.55 wouldn't that rasie that RPM at highway speeds?

[FxRacing282]

yeap! atleast 500rpms

[HOrnbrod]

right now if i'm in fifth doin 120 (Km/h :Canadaflag: :D ) on the highway It revs at like 2000... and thats just bareable with the "muffler" i'm running and I have to keep gas mileage in the equation. So if I were to switch to a 3.55 wouldn't that rasie that RPM at highway speeds?

 

Before regearing (3.55): 65MPH = 2100 RPM

After regearing (4.11): 65MPH = 2300 RPM

 

Original tires: 225/75/15

Current Tires: 31x10.5x15

 

Original MPG: 14-17 MPG

Current MPG: 17-19MPG

 

New Performance: Priceless

 

And yes, I did change the speedo gear and checked the speedo/odometer w. GPS and w. local cop radar. Do the math; 3.55 gears should work for you, depending on your tire size.

[Pete M]

Higher rpms doesn't necessarily directly equate to more-gas-used. If the engine moves towards its sweet-spot, it'll take less gas per firing to maintain the speed, plus it'll use less gas to get up to speed. It's all about putting it in the right spot in the power band. After you do the swap and you can't wipe the smile off your face when you first feel that pop of extra power from a standstill, gas mileage won't matter anymore anyways. :D If you want to go the extra mile, find an Explorer 8.8 with disk brakes, but for now the Dana 35 should do you fine and be cheap too. When you convert to 4wd, then you should definitely look into the 8.8 and get even better gears and more strength at the same time (factory 4.10s are out there).

[MJCanadian]

So 3.55 with stock-ish sized tires should give me a good boost, and if I were to go with 31's or 33's in the future i'd have to upgrade to 4.10.........starting to see the picture now 8) and gas mileage is proportional to the load and not the RPM's :D . As far as finding a D35- are they only found in Cherokees? or are they pretty common in all Chrysler trucks -calling the wreckers tomorrow moring

[Pete M]

The axle you're looking for are found under pretty much all of the older small Jeeps TJ/XJ/YJ/ZJ/MJ. Which model you buy from will affect how much bracketry you have to cut off as TJs and ZJs are 4 link in the back. The Dana 35 is the most common, but the other common one is the Chrysler 8.25 axle. It's technically better than the Dana 35 and the later versions (late 90s) are 29 spline and on par with a Dana 44. Bonus points if you can find a ZJ unit with disk brakes on it. :D

[HOrnbrod]

So 3.55 with stock-ish sized tires should give me a good boost, and if I were to go with 31's or 33's in the future i'd have to upgrade to 4.10.........starting to see the picture now 8) and gas mileage is proportional to the load and not the RPM's :D . As far as finding a D35- are they only found in Cherokees? or are they pretty common in all Chrysler trucks -calling the wreckers tomorrow moring

 

As far as your gear ratios are stated - correct. But you have to look further down the road to save you extra work and $$. If you plan on wheeling later, do what Pete and Dirty and everyone says and dump the D35, and swap in a D44 or 8.8 with the gears you want already in it. If your rig is strictly going to be a D/D and you're not going SOA, keep your D35 and regear it yourself. It's easier to change gears that swap out the entire rear, IMHO. If I can do it anyone can do it ( and who knows, I was probably lucky). It takes a lot of research, ask questions from the guys here that have done it before, and if you feel comfortable, go for it. And I for one would not want to take a chance on a used rear w. questionable gears; I'd rather put in NEW gears and know what I have. Plus you'll have to most likely buy new or transfer brake parts, seals, etc. A new set of D35 ring/pinion gears and a master install kit can be had for less than $200, and who knows with a used rear how many $$ you'll end up spending.

[rockhardzj]

The axle you're looking for are found under pretty much all of the older small Jeeps TJ/XJ/YJ/ZJ/MJ. Which model you buy from will affect how much bracketry you have to cut off as TJs and ZJs are 4 link in the back. The Dana 35 is the most common, but the other common one is the Chrysler 8.25 axle.

I couldn't agree more. Or you can modify the MJ to a 4 link setup... :D But that's a little more involved.

 

It's technically better than the Dana 35 and the later versions (late 90s) are 29 spline and on par with a Dana 44.

'tis the reason I'm going with a 8.25 in the rear.

 

Bonus points if you can find a ZJ unit with disk brakes on it. :D

This is the easiest part. But if you pick up the discs, make sure to grab a booster/master cyl as well, the old booster/mc won't handle the bigger wheel cylinders as well, and braking will become worse with the upgrade without a matching disc booster/mc. I'm going with discs.

[MJCanadian]

You still have to drop the axle to regear it though right? If not I could consider regearing, but I hate driving my parents cars and I don't wanna have my truck off the road for more than a couple of days. I'm thinkin find an axle now, clean'er up do all the prep under the truck and on the axle so that when I bring'er into the shop I can get it up on the hoist get some buddies and do the swap in one day. Also I can always sell the axle with the 3.07 gears in it right back to the wrecker.... maybe sandblast it and jiggle-can it to see if the guy'll give me an extra $20 'cause god knows how much he'll raise his price on it if it looks good on the outside

[DirtyComanche]

You don't need to pull the axle. But unless you have a lift, you're going to hate life for not doing it.

 

 

Getting another axle to set-up is the best bet.

[rockhardzj]

If your rig is strictly going to be a D/D and you're not going SOA, keep your D35 and regear it yourself. It's easier to change gears that swap out the entire rear, IMHO.

So let's see, to swap out the entire rear axle, with correct gears, there are 8 nuts to undo from the leaf ubolts, another 4 at the ujoint straps, and undoing brake lines.and the 5 lugs on each side to swap the wheels to the new axle.

 

Doing gears requires ripping the entire axle apart, which is much more difficult in the truck, and more involved. Less room to work makes for a much more pissed off person working on it. I know from experience. When doing gears, you have to play with backlash, and pinion preload, and make sure the gears are making the correct contact so they don't wear out. It's time consuming.

 

I can drop a leaf sprung axle in 15-20 minutes, roll it out of the way, put the new one under, and bolt it all up. If you need to set your pinion angle, your best bet is to set it, tack the perches in place, drop the axle to be more accessible, and burn the rest of the way on, reinstall axle, maybe about a day for a noob for a leaf sprung axle. I suggest new ubolts for the axle, as well as new ujoint straps and bolts. About $30 total, IIRC.

 

Setting up gears, again, it takes time, and you have to be precise. It's easier outside the vehicle with more room to work, not cracking your head on stuff, and not as much nasty gear oil smell. also, when setting up outside the vehicle, your environment is more well lit, and its easier to check your work, because redoing gears sucks. Also, you have to either find a used, but great condition gearset, or buy new, and new will run about 150-175 for a D35 Then you will also want to buy a master ring and pinion install kit, and that runs about another $100 bucks, although, usually, you can resell this and get some cash back.

 

I suggest the new axle route. As Pete said, a D35 can be had cheap to free, and cutting brackets off is about the most time consuming thing to do, if you can't find a MJ axle. An 8.8 is fairly cheap, maybe $250 at your local scrap yard. They are everywhere, and have tons of aftermarket support, and chances are likely, you'll find one in the gearing you'll need. Bonus is 96+ usually has discs if it came off an Exploder.

[rockhardzj]

You still have to drop the axle to regear it though right? If not I could consider regearing, but I hate driving my parents cars and I don't wanna have my truck off the road for more than a couple of days. I'm thinkin find an axle now, clean'er up do all the prep under the truck and on the axle so that when I bring'er into the shop I can get it up on the hoist get some buddies and do the swap in one day. Also I can always sell the axle with the 3.07 gears in it right back to the wrecker.... maybe sandblast it and jiggle-can it to see if the guy'll give me an extra $20 'cause god knows how much he'll raise his price on it if it looks good on the outside

Now your getting the clue. :cheers:

[HOrnbrod]

You don't need to pull the axle. But unless you have a lift, you're going to hate life for not doing it.

 

Getting another axle to set-up is the best bet.

 

??. Did he mean "pull the axle" out as in prep to change the ring/pinion, or "pull the axle" as in swap the rear end?

[Pete M]

An 8.8 is fairly cheap, maybe $250 at your local scrap yard. They are everywhere, and have tons of aftermarket support, and chances are likely, you'll find one in the gearing you'll need. Bonus is 96+ usually has discs if it came off an Exploder.

 

All Explorers/Mountineers 95-01 will have disks. And while we're throwing out info, all explorers (even pre-95) will have the big 31 spline axle shafts. It's a good axle choice. :D

[MJCanadian]

by pulling/ drop the axle I meant do I have to unbolt the leafs etc and physically romove the whole axle to redo the gearing- wich seems the case. If I use a lift/hoist I'd only have it for a day and there's no way in heck i'm gunna take out my axel, put it on stands and fart around changing the gearing for a week (figure thats how long it'd take me not including ordering parts that I forgot to order in the first place kinda thing)

I'm pretty set on getting a D35..... maybe an 8.8 we'll see.... doing the prep and putting it in. So as far as pinion angle, is it all in the perches? I'f i'm running SUA stock setup wouldn't the regular perch angles work, just need to modify them to fit MJ springs. Or how do I figure out the pinon angle I need, just lift axle up and tach the perches when I think its ok?

[MJCanadian]

P.S sorry if the thread kinda drifted away but I started the topic so I'm fine with keeping this going, that ok Pete?

[Pete M]

If your truck is still stock, all you need to do is match the current axle. A magnetic angle finder should help out here.

[HOrnbrod]

by pulling/ drop the axle I meant do I have to unbolt the leafs etc and physically romove the whole axle to redo the gearing- wich seems the case. If I use a lift/hoist I'd only have it for a day and there's no way in heck i'm gunna take out my axel, put it on stands and fart around changing the gearing for a week (figure thats how long it'd take me not including ordering parts that I forgot to order in the first place kinda thing)

I'm pretty set on getting a D35..... maybe an 8.8 we'll see.... doing the prep and putting it in. So as far as pinion angle, is it all in the perches? I'f i'm running SUA stock setup wouldn't the regular perch angles work, just need to modify them to fit MJ springs. Or how do I figure out the pinon angle I need, just lift axle up and tach the perches when I think its ok?

 

To regear, you do not have to remove the axel assembly. You remove the diff cover, the driveshaft, and the two axles. Order your ring/pinion set in advance, and a master rebuild kit. One day is plenty of time. No worries on pinion angle, perches, etc., you're just regearing. Or am I missing something here??