Testing with Rear Tires jacked, front tires stationary.

89 XJ with SelecTrack Transfer case, Dana 44 with posi axle.

I'd like to isolate some growling noises emanating from my rear D44. I was thinking of jacking the rear wheels off the ground (on some stands) and putting it in Drive and using a mechanics stethoscope to try to isolate the sound. But then I recall that you're not supposed to have the rear wheels moving without the front's moving (for many years my XJ was exempt from provincial emissions testing because the dyno they used was only set up for 2WD vehicles. Can anyone confirm: is it OK to run the rear wheels only for a short time for some trouble shooting? Thanks for any advice.

If the transfer case is in 2WD, there should be no power transmitted to the front wheels.

XJBucko said:

I was thinking of jacking the rear wheels off the ground (on some stands) and putting it in Drive and using a mechanics stethoscope to try to isolate the sound.

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I did this just last weekend. Since my rear axle is open, I had to set my parking brake a few clicks to get the "easy" side to stop turning.

Be safe, have fun!

Hi Hypoid:

Thanks for your note.

I thought there was something weird about stationary wheels and the Selectrack transfer cases???? Pretty sure my manual says not to tow on two wheels unless the transfer case is put in neutral.

Towing cross country (as a lot of rv jeep owners do) is a lot differant than a simple test session in rwd.

Call me paranoid, but I wouldn't do it without someone in the drivers seat with a foot near the brake pedal, and I wouldn't go over ~35mph.

XJBucko said:

I thought there was something weird about stationary wheels and the Selectrack transfer cases???? Pretty sure my manual says not to tow on two wheels unless the transfer case is put in neutral.

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That's >> If you're flat towing the Jeep, the transfer case in Neutral and the Transmission in Park. Sounds counter intuitive, but that's the configuration I've heard too. :dunno:

If you're towing WITH the Jeep...with the Transfer Case in Neutral ...nobody's going anywhere.

P.S. Put the t-case in 2 Wheel drive. Jack up the rear end...support it SECURELY with jack stands (not cinder blocks)...block the front wheels...you can drive it all day like that. I'd be REAAL careful about crawling around under the Jeep while the wheels are turning though.

ParadiseXJ said:

P.S. Put the t-case in 2 Wheel drive. Jack up the rear end...support it SECURELY with jack stands (not cinder blocks)...block the front wheels...you can drive it all day like that. I'd be REAAL careful about crawling around under the Jeep while the wheels are turning though.

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xcm said:

and I wouldn't go over ~35mph...

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I read somewhere on this board that tires get very unhappy under these operating conditions and you get the speedo over 35 MPH.

I took the wheels off, let the engine run at idle with the transmission in drive. Anything other than a whirring sound got extra scrutiny. The driver side wheel bearing was making a clicking sound. Visual inspection revealed normal wear, and some brinelling on the race. I had parts on hand,so the bearing set got replaced. I feel that 90% of the noise I was hearing under load was that old bearing set.

If it matters to the OP, I also have a D-44 rear axle, with a lot of miles.

HTH