Other things to consider when lifting; gears, power, etc..?

[GreenXJosh]

Hey all,
I am in the process of shopping around and researching all that I will need to consider when I lift my XJ. I have pretty much decided to go with a 6.5" lift and 33" tires.
So, what do you guys think? I know when I increase the tire size, I am going to have to get a new set of gears (4.56), along with the other more obvious drivetrain/steering/suspension components.
But I am really concerned with the POWER issue. Will the increase of the tire size on the stock Dana 30 and 35 axles (with 4.56) be too much for them to handle? I don't want to go through all this work just to find out that my engine (or whatever else) can't hanldle such large tires, since the XJ is sort of just mid-sized vehicle. I don't think they were really designed for such large tires.

But what do you guys think? Any opinions or advice would be greatly appreciated.
thanks.

[Mudderoy]

Hey all,
I am in the process of shopping around and researching all that I will need to consider when I lift my XJ. I have pretty much decided to go with a 6.5" lift and 33" tires.
So, what do you guys think? I know when I increase the tire size, I am going to have to get a new set of gears (4.56), along with the other more obvious drivetrain/steering/suspension components.
But I am really concerned with the POWER issue. Will the increase of the tire size on the stock Dana 30 and 35 axles (with 4.56) be too much for them to handle? I don't want to go through all this work just to find out that my engine (or whatever else) can't hanldle such large tires, since the XJ is sort of just mid-sized vehicle. I don't think they were really designed for such large tires.

But what do you guys think? Any opinions or advice would be greatly appreciated.
thanks.

Keep in mind that ANYTHING can break. If you are locked then more torque on the axles etc... I have READ that D30 and C8.25 are fine up to 33" tires (locked I think). 35" tires are ok if you are NOT locked. Chrome molly's are needed for the D30 if you are 35" and locked.

That's what I remember and what I am basing my future mods from. If someone has different information please jump in.

From the majority of what I read the D35 is a time bomb waiting to go off. I would not waste my money on 4.56 gears for the D35. Get the C8.25, cheap and a direct swap in. Of course the D44, Ford 8.8, etc... would be better but require modification to make it work, the C8.25 would be a drop in.

I don't know the state of your motor, but if the road is slightly wet an I turning onto another street, I have to take it easy other wise I'll fishtail.

If the road is dry and I'm turning, I hear my 32's trying to break loose. I suspect that 50 more HP and they would.

32s with 4.56 and top end is over 100. Long term plans include a stroker but with the motor and gearing I don't have any problems with power.

[GreenXJosh]

Mudderoy,
That's good advice and what I needed to hear.
So, you got the RC 4.5" lift with 32's and you have not power problems, you say?
I will do some more research, but it sounds like my first priority should be swapping the D35 for the C8.25, then gears, then lift and tires. Yes?


I know people don't really like newbies asking a bunch of stupid questions, but as a part of my research I like to know what other XJ owners are experiencing with lifts and big tires, before I jump into it myself.

Haha, unfortunately, my clutch went out on me today, so i will have to wait a few more weeks before I can restart my shopping. I will take this time to research.

[BlueXJ]

Newbys asking questions is what we are here for. Follow the rule of thumb that muddy laid down and you will be OK unless you get real extreme in your rock crawling or mud bogging. My suggestion would be to replace the D35 first and then start the rest of your build.

[Mudderoy]

Mudderoy,
That's good advice and what I needed to hear.
So, you got the RC 4.5" lift with 32's and you have not power problems, you say?
I will do some more research, but it sounds like my first priority should be swapping the D35 for the C8.25, then gears, then lift and tires. Yes?


I know people don't really like newbies asking a bunch of stupid questions, but as a part of my research I like to know what other XJ owners are experiencing with lifts and big tires, before I jump into it myself.

Haha, unfortunately, my clutch went out on me today, so i will have to wait a few more weeks before I can restart my shopping. I will take this time to research.

Well keep in mind that off road to me is mud. I've driven her up a steep incline, parked got out, took pictures, got back in and went to the top and over. So most of my power would have been used on flat dry pavement (unfortunately).

http://xjtalk.com/images/special/Jeep_dirty4.jpg

http://xjtalk.com/images/special/Jeep_dirty7.jpg

http://xjtalk.com/images/special/Jeep_dirty3.jpg

So I haven't tried driving up a sheer rock face or anything.

The only problem I had driving up that little hill was when I got back in I had problem with traction. I think a locker or two would have taken care of that though. I had it in full time 4x4 HI in the picture above.

So I really don't think I will have any power problems as long as I have gearing.

Just to be clear, I'm no expert, and I don't want to come across that way. So anyone feel free to correct me. ;)

Yeah, and about the newbie questions, that is one of the top reasons this board is here. Everyone had to start out new and there are basic questions that must be asked. So you keep asking those questions and don't fear being bashed. If anyone, including myself, comes across like they think your question is stupid, you PM me and I'll make sure that situation is corrected.

Free exchange of information and ideas here on xjtalk! :D

[Jeep95XJ]

Gearing is what helps you keep the power you need. With the wrong gearing you will feel like you have no power. With the right gearing you will feel as good if not better than it did stock. As stated above the Dana 35 is a POS it's not even worth it's weight in scrap. Buy a 97+ Chrysler 8.25 It's a 29 spline ( 97- are 27 spline ) And will take your 33" tires just fine. If you lock it i say get alloy shafts. If not then leave it alone. 4.56 will be nice with 33"s and an auto but if you have a manual you will want a 4.11 At 6.5" you will need a SYE and CV shaft also. Not sure what kit you looking at but here is a list of what it should include.

Front and rear braided brake lines
front coils rear leaf springs
extended swaybar links
adjustable track bar and frame bracket
upper and lower adjustable control arms or long arm if thats where you want to go
Steering stabilizer.

Not included:
Id advise a steering box brace and upgraded drag link and tierod. Factory stuff cant take much and will be on an extreme angle with that kind of lift. You will also need a SYE and CV shaft as stated above.

[GreenXJosh]

Gearing is what helps you keep the power you need. With the wrong gearing you will feel like you have no power. With the right gearing you will feel as good if not better than it did stock. As stated above the Dana 35 is a POS it's not even worth it's weight in scrap. Buy a 97+ Chrysler 8.25 It's a 29 spline ( 97- are 27 spline ) And will take your 33" tires just fine. If you lock it i say get alloy shafts. If not then leave it alone. 4.56 will be nice with 33"s and an auto but if you have a manual you will want a 4.11 At 6.5" you will need a SYE and CV shaft also. Not sure what kit you looking at but here is a list of what it should include.

Front and rear braided brake lines
front coils rear leaf springs
extended swaybar links
adjustable track bar and frame bracket
upper and lower adjustable control arms or long arm if thats where you want to go
Steering stabilizer.

Not included:
Id advise a steering box brace and upgraded drag link and tierod. Factory stuff cant take much and will be on an extreme angle with that kind of lift. You will also need a SYE and CV shaft as stated above.


Thanks for the advice there. All that you listed I planned on getting already, but I did not know about the 4.11 gears instead of the 4.56 (I have a manual). I will look into that.
Looks like I am about to buy a used (supposedly restored) C8.25 29-spline off Craigslist, so that will mark the beginning of my build. (As soon as my bank account recovers from my clutch going out).

Thanks for the reassurance guys.

[Jeep95XJ]

The higers gears work better with the manual because the manual is geared lower than the auto. A 4.56 gear with 33"s and a manual would mage 1st gear good for about 6 feet lol. The 4.11 will be perfect for you. Dont spend extra $ on a "rebuilt" rear. Your going to have to gear it anyway so rebuild it at that time. Any good shop will do that as a manditory part of your rebuild anyway. All bearings and seals.

[Mudderoy]

I agree, get a 97+ C8.25 get the gears, a master rebuild kit AND a locker. ARB air locker, Detroit locker, etc... Now when the C8.25 is set up with the 4.11 gears you are done. You can go with a lunch box locker later if you like, but if you go with a selectable locker (the best choice in my mind) later you'll have to have the ring and pinion installed again.

I choose not to go this route because I was trying to get my gas mileage back up. So when I go to the ARB air lockers (eventually) I'll have to pay to have the gears re-installed.

[2000XJ]

Not to beat a dead horse, but definately scrap that D35 if you're going up to 33's. It's just not worth dealing with that weak axle. I run a Dana 30 locked on 33's with stock shafts and gearing, and so far it's held up well. On that note, when I wheel it, I will it conciously and don't mash the skinny pedal - I have seen many guys bust their D30 shafts and/or gears because of the big tire little axle thing, and even though I carry spare shafts, I don't enjoy trail repairs. Thinking about how you wheel and picking the right lines will allow you to wheel it hard and avoid breakage - but it's not to say that you'll never break it.

The 29-Spline 8.25 is a direct swap, and should be the best way to go in terms of best bang for the buck upgrade. Just remember, that when you regear, that's the time to do a locker as well so as to not have to revisit the entire process again down the road.

[mizedog]

Sorry to dig up an old thread, but I know people read them.

I noticed the OP is in Oregon. When talking gearing, please keep in mind the effect of altitude. Living in Oregon can mean sea level or way up in the mountains. I think for every 1000 feet in elevation gain, you lose 3% of your power due to loss of O2 density. I live at 7000 feet and 4.56s w/ 32s are fine and I'm going to 33s. However, if I had to make the choice again, I'd have gone 4.88s. My choice of 4.56s was effected by the need to drive to California on vacation. I didn't want to toast the engine. I run close to 3,000rpm at 80 mph. That was pushing it for low altitude. Around CO, I usually don't drive more than 60 mph. The 4.88s would have been welcomed.

I will say I was AMAZED at the power increase once I got down to California, and unloaded the XJ of all the vacation crap. That thing scarged my wife off the line!

If you're at altitude, and have a manual, I would not be afraid of 4.56s (or at least do some calcluations).

[Mudderoy]

Sorry to dig up an old thread, but I know people read them.

I noticed the OP is in Oregon. When talking gearing, please keep in mind the effect of altitude. Living in Oregon can mean sea level or way up in the mountains. I think for every 1000 feet in elevation gain, you lose 3% of your power due to loss of O2 density. I live at 7000 feet and 4.56s w/ 32s are fine and I'm going to 33s. However, if I had to make the choice again, I'd have gone 4.88s. My choice of 4.56s was effected by the need to drive to California on vacation. I didn't want to toast the engine. I run close to 3,000rpm at 80 mph. That was pushing it for low altitude. Around CO, I usually don't drive more than 60 mph. The 4.88s would have been welcomed.

I will say I was AMAZED at the power increase once I got down to California, and unloaded the XJ of all the vacation crap. That thing scarged my wife off the line!

If you're at altitude, and have a manual, I would not be afraid of 4.56s (or at least do some calcluations).

Houston is pretty flat, and I'm at sea level (or nearly so). Driving on flat road is fine. Laggy off the line, but acceptable. I have AW4 transmission with over drive. Driving 70 mph (2800 rpm) and going over a 25 foot(?) over pass I would have to kick down into 3rd gear to maintain my speed. Even the cruise control would kick down. With the 4.56 gears, it drives like it used to with the factory tires. Okay it's a little more peppy. For drive-ability, swapping to 4.56 gears was the best mod I've done.