oldroy

I'm about to change fluid in the Differential (Dana 80) Does anyone know how much fluid it takes? ??? Also plan on using Amsoil series 2000 75w90 with no modifier(I understand that this gear oil does not need modifier) to replace present fluid. I now have 16K miles on truck, about half towing my 5er. any comments, is this the right stuff to use? I tow a pretty heavy load and am concerned about the rear end. :

Haulin_in_Dixie

Get four quarts and you will have enough with a little left over.

rich

I still put in the extra oil for the limited slip wether or not the oil says it doesnt need it. Better to safe than sorry. It takes 4 qts and I use 80-90wt

Billybob

Roy, You should not need modifier for the differential if you use the Series 2000 75W-90 gear lube...I have been running the 75W-90 in my Dana 80 LSD without modifier for about 80K and have never had a problem. The only time that you may have to put the modifier in is if you have a really tight LSD unit, too much modifier isn't good either. I also do a lot of towing and the 75W-90 is great, if you are going to tow in very hot temps then I would go to the 75W-140. On the 2WD Dana 80's they need 3.4 quarts, the 4WD's need 5 quarts. <br>I hope this helps.

PourinDiesel

I changed a friends DANA 80 diff fluid (5 speed manual 4x4) a couple months back and we had to run back to Auto Zone!!<br>The darn thing took 5.5 quarts!<br><br>So be prepared.<br>My Dana 70 on my 99 takes about 4 quarts.<br>Bye the way, I have had great luck with the Valvoline Durablend 80w90 and 80w140 (I hope I remembered those rating correctly).<br><br>--Justin

Billybob

Justin, that must have been in Gnaw Bone, Indiana measurements...

Dieseldude4x4

Ram fan: Get you that Mag-Hytech rear end cover and put it on if you are real concerned. I put it on mine and the rear holds almost eight quarts now. I also use the series 2000 75X90 AMSOIL.

PourinDiesel

Billybob, <br>Maybe with the cost of Amsoil, people want to use less to save money!!<br> <br>Just kiddin'<br><br>See you at BMD Dyno day!<br><br>--Justin

Billybob

Justin, I am not going to make it down for the dyno ...I have an exam on the 4th that I need to study for. You know when you get to be my age you don't remember things as easily, so you just have to work harder at it.

Haulin_in_Dixie

Mine is a 4x4 Dana 80 and it holds four quarts. I am running Valvoline Durablend 85/140 with modifier. Got a little too much in it this time and it slips some more than it should. Getting the cover for the larger capacity sounds good for the hauling.

oldroy

Thanks guys, I went and bought the Amsoil 75W90 today (expensive stuff) One last question, does the dealer have a gasket for the plumpkin or do I use RTV? ??? thanks again for all the input, what a good site with very helpful people. ;D ;D

Dieseldude4x4

You can use RTV but it needs to be done correctly or you will have leaks. Buy the good stuff (I used the red hi-temp). Make sure the cover and the housing are absolutely oil free. You can wipe them both with rubbing alcohol or a cleaner that will not leave a residue. Make sure no more oil will run down over the surface before doing this wiping though. Put a bead on the cover (like 1/16 thick or so) and the housing making sure to go all around all the bolt holes. Let it tack up like the tube says. When I did mine (on my last truck), I put the cover on just finger tight (just till it started to squish out) after the RTV just skinned over and left it set over night. Then came back the next morning and tightened everything up and filled the housing up. No leaks at all. The stuff is a miracle cure IF you use it right. Good luck.

TPilaske

I used the Permatex Ultra Black when I had my stock cover on. Get the Mag-Hytec, it has a built in O-ring, plus the extra fluid capacity is great! ;D<br><br>Tony