Questions about transmission, fluids, springs, horsepower, and more

They replaced the rear main seal and the oil pan gasket, not the valve cover, and it is probably the cause of the minor oil leak. I suggest Felpro kit with the bolt seals
The Toyota dealer told me they changed it. But I never asked for paperwork. The valve cover looks brand new on it. So I am hoping it is good to go. I will take a picture, if you don't mind giving me your onion on it.
 
Hey Jerry,
So, if I'm going to spend the money I should just jump to the 5.38. This jeep sits in my garage and I rarely take it out. Although I do plan on taking some camping trips with my kids soon enough.

Until then is it smart to click the OD off ?
Is it a Rubicon model?
Unfortunately the highest you can go in a non-Rubicon is 5.13. 5.38 and 5.89 gears only work in Rubicon models
 
I'm not Jerry, but I would advise 5.38 gears also when you do. It's not as low as you would think when driving and it will work with 35's should you choose to go that route later. I have 5.13 gears and 35's and it is adequate. I have the same transmission as you but I do not have a Rubicon so 5.13 is as low as my Dana 30 front axle can go. Your Dana 44 front can go lower to 5.38 which will work with 33's or 35's. A touch low with 33's but still ok IMO.

I do advise a transmission cooler at some point soon. You can install the fancy Derale unit that is direct fit and goes underneath on the frame rail. Or install one on the V bars in front of the radiator.

I believe Jerry runs the Derale unit underneath and has a write up on it.
Thank you. I appreciate all the knowledge I can gather. I just want to make sure I am taking care of this thing.
 
I just saw you do have a Rubicon. Personally I would go with 5.38 in that case. A little extra torque won’t hurt. The only thing you might have to be careful of is driveline vibrations. Do you have a rear CV driveshaft or a stock driveshaft?
 
The Toyota dealer told me they changed it. But I never asked for paperwork. The valve cover looks brand new on it. So I am hoping it is good to go. I will take a picture, if you don't mind giving me your onion on it.
Sorry I meant opinion.

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I just saw you do have a Rubicon. Personally I would go with 5.38 in that case. A little extra torque won’t hurt. The only thing you might have to be careful of is driveline vibrations. Do you have a rear CV driveshaft or a stock driveshaft?

What is CV mean? Can I spot it by looking at it?
 
What is CV mean? Can I spot it by looking at it?
CV stands for Constant Velocity. The stock rear driveshaft has two U-joints, one at each end. Aftermarket driveshafts typically have a Double Cardan joint (A type of CV joint) at the transfer case. You can identify double cardan joints because they have two u-joints together.

Your stock front driveshaft is a CV shaft. If you look at it, it has two u-joints at the transfer case instead of one, or three joints total.

So if your rear driveshaft has three u-joints instead of two (just like the front) you have a CV shaft. If you’re unsure, take a picture of the rear driveshaft where it bolts to the transfer case.
 
CV stands for Constant Velocity. The stock rear driveshaft has two U-joints, one at each end. Aftermarket driveshafts typically have a Double Cardan joint (A type of CV joint) at the transfer case. You can identify double cardan joints because they have two u-joints together.

Your stock front driveshaft is a CV shaft. If you look at it, it has two u-joints at the transfer case instead of one, or three joints total.

So if your rear driveshaft has three u-joints instead of two (just like the front) you have a CV shaft. If you’re unsure, take a picture of the rear driveshaft where it bolts to the transfer case.
Here is a picture

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That is in fact a double cardan shaft. This is a good thing because it significantly reduces the odds of driveline vibrations after regearing.

If installed correctly, the differential pinion should be at the same angle as the main part of the driveshaft, plus or minus a degree (usually a degree lower).
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So far it looks like whoever built this thing knew what they were doing. A lot of people cheap out and simply drop the transfer case skid.
 
That is in fact a double cardan shaft. This is a good thing because it significantly reduces the odds of driveline vibrations after regearing.

If installed correctly, the differential pinion should be at the same angle as the main part of the driveshaft, plus or minus a degree (usually a degree lower).
View attachment 163307


So far it looks like whoever built this thing knew what they were doing. A lot of people cheap out and simply drop the transfer case skid.

Thank you are all the information you are feeding my way. I am new to this stuff. So forgive my ignorance.

I noticed when I first saw it doesn't have anything crazy, but it seems as though they built it to be dependable. Which is what I was hoping for.

I was worried I jumped on the first Rubicon I found, but I am beginning to become comfortable with my purchase.
 
Okay,
One last question and I will stop for today. If I buy the OEM MOAB wheels. Will the tires be inset? Because the tires that are on it are 33x12.5x15 on15x10 wheels. Those Bushwacker fenders stick way out. I guess i'm worried with the OEM wheels it will look funky. If the wheels are sitting in too far. possible spacers?
 
Okay,
One last question and I will stop for today. If I buy the OEM MOAB wheels. Will the tires be inset? Because the tires that are on it are 33x12.5x15 on15x10 wheels. Those Bushwacker fenders stick way out. I guess i'm worried with the OEM wheels it will look funky. If the wheels are sitting in too far. possible spacers?

20200521_115546.webp
 
Factory wheels have too much backspacing for 12.5" wide tires which means a factory wheel would position the tire's inside sidewall too close to the suspension and cause rubbing. Factory wheels have 5.25" to 5.5" of backspacing, the amount of backspacing you want is closer to 4".

This is how the backspacing is measured, the yellow tape measure is measuring it... from the inner-most edge of the wheel to the wheel's mounting surface.

Wheelbackspacing.jpg
 
Yes those are large enough to significantly reduce performance. The correct cure for that is to regear the axles to 4.88 or 5.13, though I'd go 5.38 if you think you might some day get to 35" tires. Those ratios may seem too low but they're actually correct for your particular transmission and they're what would work best for the street. Those are not "off-road" ratios though they will work well offroad too.

Regearing is not cheap but it costs less than a supercharger which would still have to work into an incorrectly geared Jeep whose engine is forced to struggle with the low rpms caused by the factory gear ratio inside your axles.
Hey Jerry,
I see your in Southern California do you know of any reputable shops for rehearing my jeep? I dont plan on going 35" tires, but I am still leaning towards 5.13. It just seems to bog down too much on all these california hills.
 
My uncles neighbor has been doing this for years at an offroad shop. He has a full shop in his backyard. I am going to see what he would charge. But I want to reference a reputable shop and see if the price would be close to include a warranty.
 
Hey Jerry,
I see your in Southern California do you know of any reputable shops for rehearing my jeep? I dont plan on going 35" tires, but I am still leaning towards 5.13. It just seems to bog down too much on all these california hills.
Martin at Mobile Gears, they do gear installs Saturdays in Corona in a shop they rent space from. During the week they go to different locations installing gears, that's all they do. They have a superb reputation even with Revolution Gear & Axle, that's how I found out about them. He installed a replacement set of gears for me in my rear axle (made the mistake of using a synthetic gear lube and they got too hot during the break-in) and it went perfectly, no problems.

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