Jeep Creep Answers Reader Tech Questions

Apr. 12, 2011 By Jim Brightly
Have a Jeep tech question for the Jeep Creep? Send an e-mail with your name, vehicle year, model and a detailed description of the problem to Jeep Creep at Don’t forget to be as complete as possible with the description of your Jeep and its problems.

Previous Jeep Creep Q&As:

February 2011

January 2011

One Jeep recall this month.
11V145—Chrysler is recalling certain model year 2010-2011 Jeep Wranglers manufactured from July 12, 2010, through September 10, 2010. Some vehicles may experience a degradation of fastener torque for various front and rear axle attachments to the chassis module. This could result in noise, or ultimately, degradation in steering and handling characteristics, which could lead to loss of directional control of the vehicle increasing the risk of a crash. Dealers will re-torque all 19 fasteners to the maximum residual torque values. This service will be performed free of charge. The safety recall began on March 24, 2011. Owners may contact Chrysler at 800-853-1403.

MB Powerplant
I have a “41-”45 MB Jeep that I am going to put back on the road. I have all the parts except what I believe is the most important part, which is the engine. The engine that was in my Jeep when I bought it in 1975 was an F4-134. If possible, I would like to put that same engine back in my Jeep. So what I would greatly appreciate from you would be any information on cost and availability of this engine, or any information on what newer engine would in the engine compartment without having to do any large modifications to the Jeep. As I said I have all the other parts to the Jeep. Thank you for any help you can give me with this problem. Please include ballpark prices, if possible.
Jose Martinez

Jose, there’s no way I can give you prices (I don’t even know where you’re located). If you want to stick with an MB engine, look at However, I’d highly recommend an AMC or Chevy 4-cyl. engine. They’re easier to work on, find parts for, and are more reliable. See Advance Adapters’ website for parts availability.

Grand Cherokee
I just bought a used 2006 Jeep Grand Cherokee Limited with the 5.7L Hemi. It has 60,000 miles and the transmission “bumps” when I put it in and out of gear, or if I am in Drive and am going around 25 mph (shifting bumps when transmission changes gears). It’s almost like the feel of a manual transmission when you are driving too slow for a higher gear. Any suggestions?
Dan Boyd

Take the Jeep to a dealer or AAMCO and have the transmission and transfer case completely serviced, including replacing the fluid with new ATF. You may also want to change the fluid in the differentials as well. Start off with fresh fluid everywhere.

Whining YJ
I have a loud squealing or whining noise coming from my ‘94 Jeep YJ. It sounds like it could be a vacuum leak coming from the driver side near the injectors.

If you’ve eliminated the fan belt, while the engine is running (and whining) use a spray can of WD-40 and spray around the area in which you think it’s leaking. If it’s a vacuum leak, the WD-40 will cause the engine to idle a bit faster. The spray will allow you to track the leak down.

Comanche Wheeler
I have a 2WD 1991 Comanche 2.5l 4-cyl. 4-speed. I want to convert it to 4wd and have a 1994 4.0 Cherokee. Will this work?
Brian Fitzgerald

Brain, the short answer is “Yes!” All the parts are interchangeable. You could even put the 2WD stuff back on the Cherokee and sell it for a few dollars.

Interchangeable Pitman Arms?
I need to know if the Pitman arm out of a 1989 Jeep Cherokee is interchangeable with a 1987 Jeep Wrangler?
Billi Thorington

No. Check for the proper part.

Gears for Unlimited
I bought a 2006 Jeep Wrangler Unlimited that was already lifted and has 33-inch tires. I am pretty sure that the previous owner did not change the gears when he lifted and got boggier tires because when I am on the highway going up a slight hill there is no power. It’ll max out at around 75 mph in 6th gear and that is with the pedal to the metal. How do I find out the gear ratio on the Jeep now, and how do I determine what new gears to get. I want it to be fuel efficient but I also don’t want to get passed by every car on the road. It would be awesome if you could help me out.
Gray West
Duke Performances

Is it a Rubicon or some other trim level? There are several ways to tell the gear ratio, though. One: look at the tag on one of the differentials; two, go to Jeep’s website and see what ratios are available for your model. The 2010 and 2011 models didn’t change their available gear ratios. Rubicons have 4.10:1 gear ratios, which are relatively unaffected by 33-inch tires. However, it’s best to service both differentials and locate the ring gear number to determine the exact ratio. If you wish to change gears, go to the gear calculator at and you can determine exactly what gear ratio you’d prefer for your driving habits.

Synthetic Lube
I have a 1992 Jeep Wrangler YJ. My Jeep has a 2.5 4-banger with the AX-5 manual transmission. I have been hearing that Chrysler put out a TSB telling all service techs to use synthetic 10w30 instead of the “normal” 75w80 GL-5 oil. Any word on this? I also heard this applies to the AX-15 transmission as well.

I haven’t heard of this TSB. The only TSB that I can find states do not use any lower viscosity fluid or damage can occur to the transmission. You’ll have to check with a dealer.

From the ‘Stan
I just bought a stock 1999 Wrangler with 4.0L engine and 5-speed manual transmission. I have had CJs in the past and have built them up myself. This ‘99 is very clean and I want to add a lift, tires, gears and lockers. I am currently in Afghanistan and connectivity is so slow that it makes it difficult at best to research options in a timely manner. I think I want 33”-35” tires and a suspension lift (2”, 4” 6”?). I have looked at complete kits but side by side inventories of the components don’t match. I am competent and have a large garage to do the work. My main concern is getting everything I need to have a nice off-road vehicle but not to the extent of a pro crawler. I have a budget of $5000 to get tires, wheels, gears, lockers, lift and winch. Is it possible to build something nice that performs great at this price? Can you advise me of what I need?
CSM Dan Kerrigan
Task Force Rakkasan
FOB Salerno, Afghanistan

First of all, Daniel, let me thank you for your service. For 35” tires, I recommend a 4” lift and controllable lockers. I also strongly suggest that you gusset the differentials and axle tubes to strengthen them for the extra grip of the tires. You’ll also want stronger axles. Next, although the following link is for a Cherokee XJ we’re building, all the manufacturers that I’ve listed in the article have applicable products for your TJ and I highly recommend all of them. Check out this story for a list of parts we’re using:

No Heatin’ Heater
I have a 1997 Jeep Wrangler TJ Sport 4.0-liter with a 5-speed. My heater works in all phases, but it just seems like it does not blow with the same intensity it used to. Have you heard of this before and if so what is the fix?
Steve Main

If the blower motor sounds just like it did before this started, it’s in your heater’s tubing or duct system. Examine the ducts for looseness, tearing, etc. Sometimes lint/debris gets in the ducts or on the heater core and slows the air down.

As usual, each month, I’m shouting out a huge THANK YOU to Paul Schoop at Rock Lizard 4x4 in Kingman, Arizona, for his invaluable assistance in answering many of the Jeep Creep questions. Newsletter
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