Call up Allen at Allen’s OffRoad. He’ll steer you straight as to exactly what you need and give you a good deal on REvolution gears. Or just get the shop you choose to buy the gear sets, which is the smartest way to go.
Which gears should I go with?
- Thread starter Jon Wildes
- Start date
He is on the forum. Here’s his website...He’s a good guy and very helpful.
https://www.xf_vendor_spam_management/index.php?route=common/home
fourmustangs
TJ Enthusiast
Wish I could find some rigs to test drive with 35's and 33's with different ratios to truly feel the difference. As 4.10 ratio feels ok with 33's at 70mph and low speed crawling. 13-14 mpg highway at 70-75 mph
It's hard to advise you on that without you having provided any info on your Jeep here or in your empty Profile. Things like model year, engine, transmission type, and wheeling/driving needs are all critical to making valid recommendations.
fourmustangs
TJ Enthusiast
Your 42RLE has an ultra-steep .69 Overdrive ratio which means it drops the engine rpms way down (too low) once it shifts into Overdrive. Because of that you need to gear your axles substantially lower than most would think is appropriate or understand. For 33's you want a minimum of 4.88 but 5.13 would be better and actually ideal for your 33's. Really.
I have an 04 Rubicon with a 42RLE and it was lugging/dying with 4.88 gears with 35" tires. I regeared to 5.38 last year and it really improved every dramatically. Even my mpg improved from sub-12 to mid 14 mpg. Engine runs a lot better on the highway too, it no longer lugs. And actually, 5.38 is barely enough for that transmission and 35's. If I could gone even a little deeper than 5.38 it would have been perfect. I'm talking highway performance since I usually have a 2-3 hour drive to go to my favorite wheeling destinations.
fourmustangs
TJ Enthusiast
With an automatic Rubicon DEFINITELY go with 5.38 for your 35's, you won't regret it.
Thanks, I understand the downfalls of the 42RLE OD. I was using GrimJeeper's program to put in your combo to see what RPM's you were running for different speeds. I'm shooting for similar RPM's with my set up, but trying to get a sense of the compromises I'll see with the 42RLE.
I drove a 5 spd with 4.88s and 35s. It was great, though I did notice a slight drop when climbing a hill at 65. I am going a step deeper with 5.13s, it'll perfect for the steep grades in CO that I regularly drive.
It seems i have gotten mixed answers on this. Some say 4.88 ad others say 5.13. i think i will go 5.13 ive heard its better to be lower than higher.
Totally up to you. I think in Memphis with relatively flat ground 4.88s would be good. Here in CO with steep grades (up to 9.5%) the deeper the better IMO.
would it hurt me to go with the 5.13? i just got a quote for them from Allen's Offroad.
If your '97 has the 5-speed, you could go either 4.88 or 5.13. 5.13 is better offroad but if your Jeep still gets driven on the highway a lot I'd go 4.88. I ran 4.88 for years in my previous '97 with 5-speed, 35's, and 4.88 gearing and its highway engine rpms at 70 mph were right at 2700-2750 which was ideal. I don't think I would have wanted them higher than that. I'm all about low ratios like 5.13 and 5.38 and run 5.38 in my current '04 TJ with 35" tires but it has the turd 4-speed 42RLE which makes 5.38 the only good choice. But for your 5-speed? If it sees much street/highway time I'd go 4.88.
When off road sometimes I wish I went with 5.13 but all other times I am very happy with 4.88. If I was to do it all over again I would still go with 4.88.
4.88 will be a night and day difference offroad compared to 4.10. In 4 wheel low I release the clutch and the jeep wants to climb anything with minimal to zero input from me.
4.88 will be a night and day difference offroad compared to 4.10. In 4 wheel low I release the clutch and the jeep wants to climb anything with minimal to zero input from me.
the guy before me had 4.56 gears in it so its not gonna be a massive difference. im guessing the majority of the damage to the teeth happened before me. What are some things to avoid (usage) so this doesn't happen again.
Make sure the gears are broken in properly and my strongest possible recommendation for the gear lube used during the break-in is a conventional gear lube... not a synthetic.
Here are the break-in instructions from Revolution Gear, they are typical of what's needed....
Ring and Pinion Break in Procedure
Ring and Pinion Break in Procedure
When installing a new ring and pinion it is recommended to properly break in the new components. The proper break in procedure will extend the life of the components and help with the prevention of premature failure usually caused by extreme heat.
Although your new ring and pinion is “Lapped” from the factory for smooth quiet operation, they will still need to be broken in once they have been installed. A new ring and pinion will initially run hotter when new and can cause extensive damage if the temperature exceeds ideal operating conditions for an extended period of time. The suggested break in procedure is as follows,
- The first drive with the new ring and pinion should be under normal driving conditions (No hard starts, No racing, No off-roading, No towing and not at Highway speeds).
- The vehicle should be driven 15-20 minutes around town, normal stop and go driving. Then you should let the axle assembly “Completely Cool” (this will allow the gear oil to cool down so it does not reach temperatures that will break down the oil, causing loss of protection)
- Repeat the 10-15 minute drive and cooling off period 2-3 times
- Then you will want to drive on the highway and repeat the process at least 2 times abiding by local speed laws but not exceeding 65 MPH, be sure to let the axle assembly completely cool between drives (very important).
- Lastly you will want to change the gear oil after the initial 500-1000 miles and your gears are broken in correctly.
- Note: If vehicle will be used for towing, repeat the break in procedure the first time it is used to tow.
(Recommended gear oil is an 85-140W, Non-Synthetic, GL5 grade or Higher, Name Brand Oil. Please note extreme weather conditions may require alternative weight oil so be sure to consult a local mechanic or lube technician for recommendations)
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