picked up my XJ d44 today...what next?

alright this is an opinion thread. i want your opinions.

i picked up my XJ d44 today for $150. great deal! i have a d30 front and 35's. currently i have 4.56 gears. should i regear the front to 4.88 and gear my new d44 for 4.88, or should i just gear my d44 for 4.56?

brandon

or i've thought about sticking with 4.56's and adding a header for more low end torque. basically engine mods instead of lower gears. i could live with being a little underpowered at highspeeds, just wondering who has 35's with 4.56's and chooses to make engine upgrades

brandon

I run 4.56/35's, with a tired 4.0, goes down the road just fine.

I ran 4.56 on 35's on my 01XJ. (D-44 rear, D-30 Front) Performed fine.
Wanted a better crawl ratio so I added the tera low kit and 4.88's. Performs better now (locked D-44's front and rear)
4.88's will bring the speedo closer in line with the 35's.
It's probably a matter of money and what you want to crawl over.

shimmy said:

or i've thought about sticking with 4.56's and adding a header for more low end torque. basically engine mods instead of lower gears. i could live with being a little underpowered at highspeeds, just wondering who has 35's with 4.56's and chooses to make engine upgrades

brandon

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Btw my Borla header and FlowMaster 50-series, I feel that I've LOST low-end torque. I'm running 4.56's w/35's, and if money and time were no object, I'd regear it to 4.88's.

shimmy said:

alright this is an opinion thread. i want your opinions.

i picked up my XJ d44 today for $150. great deal! i have a d30 front and 35's. currently i have 4.56 gears. should i regear the front to 4.88 and gear my new d44 for 4.88, or should i just gear my d44 for 4.56?

brandon

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looked at the contact patch on the gears for 4.88's in a d30? i read somewhere that it was 5/8's of one tooth... not all that strong...

how many people do you know who've blown up 4.88 gearsets? I personally know at least 6 folks in our club with 4.88's in their TJ's, and none have had any trouble. I'm sure folks have broken 4.88 gearsets, just like I'm sure folks have broken 4.56 gearsets, but running 4.88's isn't guaranteed breakage (not like running a locker with 33's on a D35).

XJ_ranger said:

looked at the contact patch on the gears for 4.88's in a d30? i read somewhere that it was 5/8's of one tooth... not all that strong...

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BS.......old internet wives tail.

I've never bought into the heresay about higher (numeric) ratio gear sets being weaker. Oh, I know there is a limit, but not on production gearsets. Early Jeeps came from the factory with 5.38 gears in D25's and D27's, and Toyota's regularly run deeper gears. Yes, there can be slightly smaller gear contact, but gears are spriral cut and so there is always muliple tooth engagement. Plus, there is also a leverage advantage with the slightly smaller pinion of the higher ratios, which should easily counteract any smaller tooth contact.

I can't make a conclusive technical argument that higher ratios aren't slightly weaker, but neither do those who promote internet fantasies. I can say confidently that there isn't enough of a difference to affect making the decision to run the deeper gear ratios.

As far as changing to 4.88's, I wouldn't hesitate. I also would put more weight on advice from those who have run it both ways. We all tend to justify what we're running. I ran 4.56's with 33's and wished that I had 4.88's. When I went to 35's I also changed axles and went with 5.13's, and I was much happier with that ratio. It's all a matter of how often you have to drop a gear.

I won't comment on the 4.88 D30 gears, but I will comment on the Toyotas. I've been following the Toyota boards closely for the last 2 years or so, and they consistently have major problems with 5.71 gears. Failures with 5.29s are less common, but still a fair possibility so many guys stick with 4.88s even though they really wish for something well into the 5s with the little 22re. FormulaToy (new Toyota based comp series) only allows 4.10 gears because of the failures with anything deeper.

BrettM said:

I won't comment on the 4.88 D30 gears, but I will comment on the Toyotas. I've been following the Toyota boards closely for the last 2 years or so, and they consistently have major problems with 5.71 gears. Failures with 5.29s are less common, but still a fair possibility so many guys stick with 4.88s even though they really wish for something well into the 5s with the little 22re. FormulaToy (new Toyota based comp series) only allows 4.10 gears because of the failures with anything deeper.

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OMG, another ditto. What is the world coming to?

CRASH

P.S. I've personally replaced two 5.29 sets for some cats. 4.88's are the deepest you want to go in a Toy 8" with any sort of power being applied (i.e. 4.0)

i am schooled

Since you have 4.56 gears in your 30 already, I'd stick with those and gear your new xj 44 with the same. Going to 4.88's would be nice, but not worth the $ to regear your front axle.

bustercat said:

Since you have 4.56 gears in your 30 already, I'd stick with those and gear your new xj 44 with the same. Going to 4.88's would be nice, but not worth the $ to regear your front axle.

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Good point bustercat. Go as low as you can go with your axle gears as long as they are strong enough, but 4.56 to 4.88's isn't that much difference and not worth the expense.

shimmy said:

or i've thought about sticking with 4.56's and adding a header for more low end torque. basically engine mods instead of lower gears. i could live with being a little underpowered at highspeeds, just wondering who has 35's with 4.56's and chooses to make engine upgrades

brandon

Click to expand...

I've talked with several shop owners around here, a couple of the tech reps from Edelbrock and Borla, and each has stated that too big an exhaust will rob low end power from your engine. The beast needs a little back pressure to keep low end torque and power from disappearing.

As with your original request, stick with the 4.56s.

hmmm... what gives me better gas mileage, 4.56 or 4.88 with 35's? why not just go to 5.13's and 35's, i have a 98 auto...? i almost feel like going with 5.13's and finding a HP44 narrowing it and 5.13 in there too. if i put 4.88 in then i won't have enough $$$ to regear the front right away... i'll have to wait a few months.

brandon

if you regear, you gotta do both axles at the same time, or remove the driveshaft for the axle that didn't get regeared. 4.88's are as low as you can go in a D30, so you'd definitely have to go with some sort of D44 front or larger to get lower gears.

Jeepin Jason said:

if you regear, you gotta do both axles at the same time, or remove the driveshaft for the axle that didn't get regeared. 4.88's are as low as you can go in a D30, so you'd definitely have to go with some sort of D44 front or larger to get lower gears.

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yeah i figured that much, but i just don't know if a wanna go that long without 4x4 if ya know what i mean...if i go to 4.88 in the rear

Subscribing to thread

Superior just released a dual pattern (holes for both 5x5.5 and 5x4.5) chromemolly rear shaft for those, and it currently is costs less than the normal superior heavy duty rear replacement axle as they haven't had their meeting to determine the pricing on it. This is straight from Joel at Superior. And I just ordered a set yesterday through Dave at Shaffer Offroad (DSI on Pirate, 1-775-885-9944). They run $105 a side until the price gets bumped up into line with their other chromemolly stuff. Joel mentioned that would be in a week or so.

Part numbers are:
Left shaft: PA6170S
Right shaft: PA6170L

I ordered a set of their 4.89s and a master install kit on the same order. There's a one week wait on the gears and I asked that they all be shipped together. I'll shoot pics when they arrive if you'd like.
Just a head's up.

...Frank

since you have 4.56's already in the front, I would just re-gear the 44 to 4.56. I went with another option. 4.88's and detroit in the rear :laugh3:

My Jeep is DD and I need it almost everyday. I didn't want my jeep down either. I also have a vac disco axle. So I figured time to replace and go to the larger U-joints.

Found the D44 100.00
Found a D30 out of a 96' 100.00
Drove both to the axle guy, droped them off and drove home in the XJ

Positives
Cheaper, easier for the gear guy to work on them (might even save the 100)
No down time in the jeep
No more vac disconnect
Larger U-joints
Not as many miles as mine had

Negitives
cost 100.00 to get the front D30
Spending money on a D30, but what the hell