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5 Posts
Discussion Starter · #1 ·
Hello everyone.

The frame on my '98 Sahara has succumbed to O2 poisoning. Time for a swap. Picking up a reconditioned, rust-proofed, painted 2006 TJ frame in a few days. I have several questions, and hopefully the gurus can offer some answers. Thanks in advance for all of your excellent support.

My Sahara is stock as a block, except for the Borla 2 piece header that I installed at 57,xxx miles back in the way early 2000's. I use the Jeep for camping/kayaking/hiking and sometimes as a daily driver for weeks at a time. 5 speed manual, original clutch. Ordered in the late fall of '97, picked up on 10 Jan '98. Some parts are '97 specific, some are '98 (has the slider HVAC controls).

I will do a write up as I am performing the swap, with pics and a view of the actual costs. There is a famous (?) vid on youtube where 3 pros do a complete swap in 5 hours. My timeline is eleven days working 10 hours a day. I have a Danmar maxjax lift and a 2 car garage, and some decent tools. I will have help here and there but nothing I can count on for long periods of time. Advil and whisky will be my friends.

Now the questions. If there are any suggestions for reasonable upgrades, I would love the advice. Trying to have as much of the replacement/upgrade items on hand so I can roll as fast as possible.

'06 FRAME vs '98 FRAME
Anything that is different between the two other than the steering box and steering box mounting?

I understand the steering box is different from '98 to '06. If I switch to an '06 box, will my hoses and linkage still work? Is it better to modify the mounting and stay with the '98 box? I will be replacing the box either way.

Still on the original clutch. Time for a replacement. I have all the bits to do the replacement. Anything else I should be doing while I have the driveline apart? Engine main seal? Should I do the replacement with the engine/trans in the old chassis or in the new chassis? I am thinking in the old.

Should I replace the old suspension and body mount bushings? If so, I will stay with original rubber bushings. Is there a kit? Haven't seen one for the original rubber bushings, seen plenty for poly.

Skid plate is mostly rust and I will install a new skid plate and new straps. Any advice or tips or gotchas? Anything i should do to the tank while I have this level of access?

I plan to use new stainless lines. Any vendor or brand suggestions? What about mounting clips-is there a kit? Front disc/rear drum, and already have new rotors/discs/shoes all around, plus a new e-brake splitter is already installed.

I plan to replace the shocks with stock items. Any suggestions for reasonable upgrade or brands?

Can I re-use the originals or should I replace? Upgrade suggestions? I have seen where you can spend *a lot* of money here. Worth it?

I have a leak in the exhaust manifold gasket, and I will replace the gasket. Any tips/gotchas/suggestions here?

Any other suggestions while I am in there? I have already proactively replaced all of the engine management sensors, and the exhaust is new as well, including the cat, all the way back.

The system has a leak. I need to replace the dryer and the o-rings. Not a big fan of the way the hoses connect. Suggestions here on the system?

Stock, and I will keep it stock. Any suggestions or tips for minor upgrades here or maintenance items I can do while it's all accessible?

Not overly fond of the plastic in the OEM item, and this is the second radiator. Suggestions for an upgrade here? I will likely not stay with stock.

Suggestions here? I don't have an impact wrench, do have a pancake compressor. Still need to get a cherry picker and some spring compressors. Have torque wrenches and pulley/pitman/ball joint pullers, and a good collection of tools, both metric and SAE. Have oxy/acetylene and propane torches, vacuum pump and refrigerant gauges and refrigerant. And the lift. I am so grateful for the lift.


Where do I find the detailed torque specs for each of the systems? What is the best system to visually ensure I have torqued everything to spec-a dab of white paint on the bolt upon successful torque application?

Any other suggestions or advice will be most welcome. I am just a home mechanic. I will treat this like any other large project-as a series of smaller projects, logically completed in series until overall project finalization.

Here is my plan:
Run the fuel down as low as possible. Liquid Wrench the hell out of the entire underbody for about a week. Drain engine oil, coolant, refrigerant, brake and ps fluids. Lift the Jeep and lower onto the wheel dollies, using chocks for brakes and leaving the trans in neutral. Remove the battery. Remove the soft top, rear seat, doors, spare, and any other extraneous weight. Unbolt and disconnect all systems and bolts between the chassis and the body (it's a bit of a list). Raise the body off the chassis with the lift and leave body lifted for the duration. Roll the chassis to the open garage bay and next to the replacement chassis. Disconnect the exhaust at the downpipe. Replace the exhaust/intake gasket. Replace clutch. Pull engine/trans/transfer case and move aside. Begin moving systems from the old chassis to the new (not sure of the order I should do this and would appreciate advice). Should I do brake lines first or last or somewhere in the middle? Should I do fuel system first or last or in the middle? Suspension and axles first, last, middle? Which way makes most sense? Once all systems are replaced and all bolts are torqued and double checked, will install the engine/trans/transfer case and axles into the replacement chassis. Will roll the completed chassis under the lifted body and reinstall the body to the chassis and reconnect all systems. Bleed and fill brakes. Bleed and fill clutch. Bleed and fill ps. Bleed and fill coolant. Vacuum and recharge A/C. Replace battery.

Sorry for the long post, and again I thank you all in advance for any and all suggestions, support, tips, and advice.


397 Posts
Mr Blaine had this to say about the frame year differences
beside the engine mounts and the steering box
"Some 97 frames, early versions have 1/2-13 weld nuts under the rear bumper. The rest of them are 12mm. 03-06 frames have a very different hole pattern for the belly skid and a different skid that goes straight across at the rear of it instead of being cut out for the muffler on the right side along with the previously mentioned pattern for the steering gear.
Anyone trying to swap between the two generations would be tempted to just get the matching belly skid but the holes for the trans mount are in different spots and there isn't an adapter for the later skid for the auto like there is for the earlier versions."

and I found this on another forum page
"The 2003 and newer frames use a different steering box and mounting pattern. The transmission skid/mounting pan also uses a different bolt mounting pattern into the frame and is retained with the use of metric fasteners instead of the earlier standard hardware. So to use a 2003-2006 frame you would have to use the newer skid and steering box- the pressure line on the box is also different just because the line goes into a different spot on the newer box."

Super Moderator
12,689 Posts
Being a YJ owner and driver, I can only add a little bit of advice, based on a long career in the automobile business, starting before 1960 and still at it after retiring in 2008.

Suggestion #1...Forget about the whiskey until the job is done and satisfactorily test driven.

Suggestion #2...Drill a small (1/8") hole in the floor over each body mount and shoot the Liquid Wrench in from the top. Use plenty.
Or, drill the small hole in the side of the body mount (under the Jeep) and stick the straw of the Liquid Wrench in there and give it a good dose.
You might even drill a series of holes in the rusty frame, one at each skid plate bolt. That way, you're soaking the top of the blind nut with the liquid Wrench and allowing gravity and the penetrating property of the oil to work downwards, rather than the penetrating properties alone to try to work upwards.
Do it daily starting now. When you're done, you can put a piece of aluminum tape over the hole in the floor or weld the hole in the side of the body mount shut. Undercoat.

Suggestion #3...Assemble all threaded hardware that doesn't require thread locker (Loctite) with Anti-Seize. Assemble all electrical connections with dielectric grease.

Suggestion #4...If you buy or borrow an engine stand, you can change the rear main seal a lot easier with the engine up side down. It sure beats doing it on your back. Read and follow the instructions closely. Use a blue Fel-Pro pan gasket kit. It comes with a RMS.

It appears you want to stay as close to stock as possible. If I were changing a frame, I'd consider a 1" body lift. Not that you'll need it at all with stock tires, but it makes it a lot easier to access some components for service and much easier to clean the underside.
I'd want rubber, not poly.

I assume you'll do the write up in the TJ build forum? I'll look for it. A lot of pics and details will help the next guy that might be planning on doing the same job.

Good Luck, L.M.

45 Posts
If I was going through all of that, I'd replace rear main seal, clutch and any other "small" jobs when easy access. I have not needed a spring compressor for stock or aftermarket (lift) springs. On my LJ or XJ's MJ coil springs. Replacement control arm bushings (new stock control arms can cost less than work and $ for just bushings) at least swap the direction of the driver's side motor mount bolt so it can be done with out having to unbolt mount from the motor to replace later. (Learned that from my 90XJ) pain in rear stacking blocks to get jack up to bottom of engine.
Good time to clean fuel tank and paint it, check /replace vent lines, rubber tank strap pads. Test fuel pump, make sure you have good ground connection for it.
I sounds like you have good plan already..

45 Posts
I'm on radiator #3 OEM replacement leaking from the day I installed it. Finally gave up on it went after market Aluminum (bolts don't fit exactly) but LJ runs 10° cooler. (Installed in Feb.) Factory one gave up on me on road trip, reason why I didn't go after market then.

5 Posts
Discussion Starter · #7 ·
Thanks guys-greatly appreciate your input.

For the bolts I need to change, is there a specific grade? Do you have a supplier you recommend? I am trying to have as much on hand prior to starting so that I can be as efficient as possible. This Jeep gets a lot of use as a daily as well as for leisure and i can't have much downtime.
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