Differential Covers--> I outsmarted myself 20 years ago.

[Matt42]

I am trying, with emphasis on trying, to remove the rear differential cover on my truck's Dana 80 differential. I last had it off when I changed the oil ahead of a long trip in 2002. So it's overdue by time, but at 85,000 miles, it is not bad by miles.

As the title suggests, I reinstalled the cover much too well and I cannot get it back off. I am looking for suggestions. What do people do when faced with stuck differential covers?

Per the Dodge TSM in 2002, I cleaned the cover and cast surfaces really well and wiped them down with alcohol. Then I applied a small bead of Permatex Gray RTV to the cover. Then I stuck it on and torqued the bolts to spec. The bolts came off OK today, with some effort. I am expecting the same issues with the front cover because I installed it the same way.

Today, I have tried everything from using a ball peen hammer whacking a flattened screwdriver to pry it off to using an air chisel with a just-now sharpened chisel. All I have succeeded in doing is damaging the edges of the cover and scoring the cast differential boss. I know I can get it off using brute-force, and also ruining the cover. If that's the answer, well, that's what I have to do. At least my wife has just now agreed to the cost of the MagHytec covers and the extra oil.

 

[seafish]

If it is only the RTV that is holding it on, take a sharp razor blade and begin to score the RTV in between the cover and pumpkin and continue going around the edges as deeply as you can

You could also try using a flexible cable wire instead of the blade to "saw" through the RTV.

That said, you should prolly also try careful application of heat from a MAP or Propane torch around the edges of the pumpkin and cover.

 

[bcbender]

You could try a long flat thin prybar (construction demo bar), hold it as parallel with the differential casting as possible and give it deliberate sharp blows with a decent size hammer to drive it in. RTV can be a bugger to get off when its sealed and bonded tight. If you can get the bar in there a little bit, then prying it off it should go, but you have to get it in there enough to pry the cover off. Another method would be using a very thin putty type knife / scraper and driving it in all around to "cut" the sealant, if you get enough of it cut, it'll pop off. Bottom line its gonna be a little work to get here done.

 

[Iron Duke II]

I am trying, with emphasis on trying, to remove the rear differential cover on my truck's Dana 80 differential. I last had it off when I changed the oil ahead of a long trip in 2002. So it's overdue by time, but at 85,000 miles, it is not bad by miles.

As the title suggests, I reinstalled the cover much too well and I cannot get it back off. I am looking for suggestions. What do people do when faced with stuck differential covers?

Per the Dodge TSM in 2002, I cleaned the cover and cast surfaces really well and wiped them down with alcohol. Then I applied a small bead of Permatex Gray RTV to the cover. Then I stuck it on and torqued the bolts to spec. The bolts came off OK today, with some effort. I am expecting the same issues with the front cover because I installed it the same way.

Today, I have tried everything from using a ball peen hammer whacking a flattened screwdriver to pry it off to using an air chisel with a just-now sharpened chisel. All I have succeeded in doing is damaging the edges of the cover and scoring the cast differential boss. I know I can get it off using brute-force, and also ruining the cover. If that's the answer, well, that's what I have to do. At least my wife has just now agreed to the cost of the MagHytec covers and the extra oil.

bcbender mentioned using a putty knife. I have used a metal putty knife to cut through old hard rtv as well on a rear diff. https://www.harborfreight.com/2-in-...MI-_6QhvGU-QIVj8LCBB0H0ggwEAQYAyABEgJVbfD_BwE


Then use a Lubelocker gasket. https://www.lubelocker.com/products/dana-80-llr-d080

 

[GAmes]

I'd try this. https://www.harborfreight.com/the-incredible-blade-carbide-cutting-rods-pack-of-2-96274.html
I think I'd try tying some strong cord to the ends rather than use a hacksaw frame,

 

[Matt42]

Thanks, everyone. I used a variation on the ideas, except the really thin HF carbide blades. What I did was to use a small ball peen hammer to drive in a single edge razor blade between the cover and the differential until it got stuck. Then I drove another razor blade right under the first one, so that they were side by side. Then I drove an old screwdriver between them and POP, the cover let loose. The gear oil that came out was a nasty dark brown color. It was time.

I've just ordered a set of MagHytec covers. I'll wrap the opened differential in plastic to keep the dust out until they arrive. And also buy some more gear oil.

 

[GAmes]

I recommend Royal Purple. My differential is the only original piece in my drivetrain.

 

[Ozymandias]

I recommend to use reusable gaskets instead of goo that has to be scraped off in pain every time you change the oil.

 

[GAmes]

That's the nice thing about MagHytec covers. The have a drain plug. I haven't had mine off in well over a million miles.

 

[Cummins12V98]

Beat the hell out of it with a large dead blow hammer.

 

[Cummins12V98]

AMZ/OIL SevereGear 75/90

 

[Matt42]

I recommend Royal Purple. My differential is the only original piece in my drivetrain.

That's the nice thing about MagHytec covers. The have a drain plug. I haven't had mine off in well over a million miles.

I am replacing two fills (front & rear) of Royal Purple with this job. And that is good to hear about the MagHytec cover. It's 110F here and humid. I don't want to have to do this job again. The drain plug sounds really good, at my advancing age. I was in my 40s when I did the job last time.

 

[SnoKing]

The drain plug sounds really good, at my advancing age. I was in my 40s when I did the job last time.

You are still a young pup, I am a WAR baby!

 

[Diesel Gunner]

When you tighten the drain plug put a bit of lube on the O-ring. Then, DO NOT crank on it to tighten. I believe that it is a 7mm Allen that is used to install and remove the plugs and dip sticks. There is a reason for that. BECAUSE THEY DON'T HAVE TO BE SILVERBACK GORILLA TIGHT! A nice snug fit is all that is needed.

OK, now ask me how I know.

 

[GAmes]

The new plugs use a bigger Allen wrench, so I too know.

Matt, I don't know about the front but the rear capacity goes up to 7 qts. Oil changes are expensive but I do mine at 50k intervals.

 

[Cummins12V98]

MagHytec fill or drain plug sticking simply find a socket almost the same outer diameter and hold socket to plug and whack it with a hammer. Shock and awe!!!

 

[Matt42]

When you tighten the drain plug put a bit of lube on the O-ring. Then, DO NOT crank on it to tighten. I believe that it is a 7mm Allen that is used to install and remove the plugs and dip sticks. There is a reason for that. BECAUSE THEY DON'T HAVE TO BE SILVERBACK GORILLA TIGHT! A nice snug fit is all that is needed.

OK, now ask me how I know.

OK. I'll ask. Are there torque specs for the bolts?

The new plugs use a bigger Allen wrench, so I too know.

Matt, I don't know about the front but the rear capacity goes up to 7 qts. Oil changes are expensive but I do mine at 50k intervals.

Oil is cheap compared to new bearings.

 

[BigPapa]

OK. I'll ask. Are there torque specs for the bolts?

Well, YEAH. There's a torque for every fastener.

 

[Matt42]

Well, YEAH. There's a torque for every fastener.

Phrased the question badly. Did the kit come with torque specs?

Either way, the covers are on their way to me and I'll get it figured out.

 

[Iron Duke II]

Phrased the question badly. Did the kit come with torque specs?

Either way, the covers are on their way to me and I'll get it figured out.

(Torque 20-25 ft. lbs}

https://mag-hytec.com/wp-content/uploads/2018/05/Dana-80.pdf