'00 XJ - Thermostat question

[gw204]

Going to be making a trip from MD to N.C. next weekend so I will be spending this weekend getting the 4.0 XJ ready for the drive. She currently has 57K on the odometer. I will be changing the engine oil, t-case oil, diff oil, coolant, t-stat and if I have time the steering and brake fluid. Also on the list is a drum brake adjustment and check belt tension.

I did a trans service at approx. 50K using Castrol ATF and plan on using the same fluid in the t-case simply because I have some left over. She got a chassis lube about a month ago.

Now for my questions:

Since I do a fair amount of trailer towing (4500 lbs max), what weight gear lube should I be using in the D30 and 8.25? I know it's in the manual but my wife has the XJ today. I seem to recall synthetic 75W-140 but I can't find it anywhere. Found plenty of Mobil1 and Valvoline in syn. 75W-90.

Edit: Found a local Amsoil dealer that may have the 75W-140 syn. gear lube.

Where can I get regular gaskets for the diffs so I don't have to rely on RTV alone? Dealer or parts store?

Is is necessary to get the t-stat from the dealer like for my '88, or can I get one at the nearest parts store?

Anything else that I should check?

Thanks.

Brian

[AZ Jeff]

D-C's recommendation for "heavy service" applications is 85W140, if I remember correctly. (FSM is at home.)

Why do you not want to rely on RTV alone? Chrysler has been using that arrangement on all their rear ends for 20 years now, and if done properly, works just fine.

Just be sure to clean the surface of all dirt, rust, burrs, etc, and use the correct grade of RTV.

[Eagle]

Factory t-stst only. Same problem -- vertical position needs a "bleed" hole in the flange, and only the factory unit has it.

[Wayne Sihler]

Try Auto Zone for the axle gaskets
Fel Pro for the D30-#RDS 55019
" " for 8,25 #RDS 55047
Black or blue RTV is recomended at assembly.They also carry the 85-140 gear lube.
Wayne

[gw204]

Thanks guys.

Jeff, I remeber reading more posts here that recommended the gasket in addition to RTV. At least it seemed like more than those stating just RTV alone. Who knows.... :)

I also seem to remember reading a post about cleaning out the housing and the gears somehow but I couldn't find it. Any advice on that one?

Lastly, since I don't have the FSM, can someone please tell me how tight I need to torque down the bolts for the housing covers? Agian, D30 and 8.25.

Maybe it was 85W-140....I'll double check when I get home.

Thanks again.

Brian

[AZ Jeff]

I have found that Chryco's plan to not use a gasket works just fine, as long as things are clean, dry, free of burrs and flat. When I change diff juice, I just scrape all the loose crud out with my hand, and then wipe with clean paper towels to get the bottom free of all residue. I do not bother to flush the housing with anything. (I don't immerse my XJ in water, so unusual contaminants are unlikely in my diff.)

I then clean the gasket surface of the diff cover with a wire wheel on a drill, scrape the surface of the casting with a gasket scraper, and wipe both faces with lacquer thinner or brake cleaner. Then it's time for a 1/8 inch bead of Loctite brand blue RTV gasket maker, (making sure to go all around each bolt hole) and let it set 15 minutes to skin over before putting the cover back on.

I don't even use a torque wrench to tighten the cover bolts--they carry no load. I just run them down snug in a criss-cross pattern, wait 5 minutes for the RTV to settle, and do it again. I would guess I am tightening to 25-35 ft-lbs, but it's not critical, as long as you are not overly energetic on them.

I have been doing it this way since the late 1970's, and have only had ONE leaker. That turned out to be rust on the cover that I failed to get off.

[Kejtar]

Use RTV only for diffs. I actually went to the dealer the first time I was changing diff fluid and asked for a gasket and they told me that they do RTV only and it's supposed to be much better for one reason or another...

As it was mentioned though... don't overdo on the RTV (don't skimp either though) put it up and let it set a bit... and then tighten 10/15 minutes later.

Kejtar