• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

4.88 gears, the good, bad and the ugly

Demonoid369

Demonoid369

NAXJA Forum User
NAXJA Member
Location
Salem, OR
D30 front
8.25 rear.
I noticed a pinion leak on my d30 so I know the axle will need a rebuild, it's 3.55 and turning 31" but I plan to go 35" at final size.
Now I know 4.88 is ideal ish for 35" tires BUT the pinion teeth contact is what has me worried.
I know there has been a lot of threads on this but I'm hoping for a update ish kinda look on it. Has there been more stripped gears or carnage from people running 4.88 for years and how severe do you wheel
?
I'm not a lead foot driver but sometimes wheel speed is needed in the Pacific Northwest, so I'm trying to figure out if I should do 4.56 or get 4.88 gears.
 
It's a Dana 30 dude. You are splitting hairs. Pick either one man. Either way the pinion is tiny compared to a 44. A lot of us have had bad luck with 4.88s but I'll do it again in a heartbeat. I am considering trying revolution 5.13s in my 30/44 on my MJ. If they break I'll swap em out.
 
I run 4.88s locked on 35's and wheel mostly rocks. Have had no issues but I also don't use much skinny pedal. But I'm not afraid to give a bounce or spin a little. Like was said, you're over thinking. Throw them in and run em. I've had them in for 2-3 years now
 
blondejoncherokee said:
It's a Dana 30 dude. You are splitting hairs. Pick either one man. Either way the pinion is tiny compared to a 44. A lot of us have had bad luck with 4.88s but I'll do it again in a heartbeat. I am considering trying revolution 5.13s in my 30/44 on my MJ. If they break I'll swap em out.
Click to expand...


I know it's a d30 lol that's why I'm asking. I'll look into the revolution, wonder if they figured out a way it give more tooth contact for the 4.88
 
Some people say do it, some people say don't....
Really it's up to you.

Me, I did 4.56's
 
I've never had issues with my 4.88's in my 30 with 35" Krawlers, broke plenty of u joints before switching to spicers though. I run chromoly shafts also.
 
I could shear 4.56 pinions on demand in my driveway..

Most people never even have an issue with 4.88s..

It's all a matter of perspective
 
Two trail runs on 4.88s in a D30 on 35s with an open carrier and a lockrite.

Runout on the carrier where the ring gear broke was .020" further out.

The open carrier of a D30 is where the real problem is.

I would never run a D30 with an open carrier on 35s. I'd shoot for a fullcase locker.

Hell I'd even consider adding a load bolt.
 
I use a lot of skinny pedal and am locked front and rear on 35s and have messed up my gears once. The cross pin broke and took out the pinion. I always seem to break something else before the gears.
 
I stayed on 33s to help keep my 30 with 4.88s alive. And if I crawled everywhere it might have worked. But wintertime in the Midwest requires wheelspeed. My girlfriend did this at the last winterfest.
af2629cedc31bb2358f494ef5963cbea.jpg


Bottom line is if you wheel with a lunchbox locker, 4.88s and 35s, you'll never feel confident that you have a reliable rig.
 
Axle wise I have nitro sleeves, and ruffstuff diff cover and I will add a truss on top. Either do a load bolt or full locker like a Detroit, I guess I'm just psyching myself out with the idea of how much torque and pressure is put on those 2(?) teeth that only come in contact on the pinion side. That's a frightening thought lol
 
I run a trussed and gusseted D30 with 4:88s and an ARB, plus 30 spline alloy shafts. 285/75/16 tires (33x11.25) with 8 years and nearly 100k miles as a daily driver, weekend wheeler, mainly slickrock terrain.

I ran 4:56's on my last rig, which I regretted. I've never regretted the 4:88's. Put a full locker up front, as others have said; the stock carrier allows too much deflection with the disposable locker types.
Spend the money once, do the job right.
 
I've seen broken 4.10's/4.56's/4.88's in HP30's. The pinion size doesn't really between them, they all are weak and like said the stock wet noddle carrier is the bigger issue.
 
Externally sleeved and trussed D30 with a heavy diff cover with bolts that fit tight to the holes, XJ D44 with truss and a full case (Grizzly) locker. 4.56's only a couple wheeling trips on it with no problems. I installed a 4:1 transfer case to get it lower. AW4 tranny helps. I am learning not to use skinny pedal, easy with the 4:1 box. I was terrified of the 4.88's so I stuck with 4.56's and installed the 4:1 rubi box.

Gear set up makes a huge difference but driving style is probably more important. Mine were set up very very tight. I will get some set up info from the shop and post back.

I run only rocks by choice, mud when I have to so I can get to the rocks.

John
 
i think if you can break the 4.88, you likely would break the 4.56 anyways. go for the deeper gear
 
You must log in or register to reply here.

Similar threads

A
2000 xj aw4 on 34s 4.88 or 5.13
2 3
Replies
49
Views
5K
Andre2000
A
V
Engine rebuild guidance
2
Replies
34
Views
6K
RCP Phx
R
M
HP Dana 30 Yukon 4.88 Ring gear pattern check
Replies
11
Views
3K
Evan03
E
V
High temp woes
2
Replies
21
Views
414
Vitzaa
V
K
WJ front axle in Xj -89
2 3
Replies
41
Views
9K
75SV1
7
Back
Top