I had my rear differential changed at the dealership because i couldnt find any 75w-140 in my area awhile back nore any LSD additive... I know strange but none of the stores sold anything like this.

When i got my car back, i talked to the mechanic and asked him did you put in the 75-140 like i asked and he said he put in synthetic and used 2 tubes of additive. I asked him what weight the synthetic oil was and he looked at me and said its synthetic. Its the stuff they use in all the Jeeps/Dodge's, and i said yes but what was the weight and he told me that synthetic doesnt have a weight rating and that is only for the normal gear oil. Another guy at the dealershio told me same thing..

Im wondering is this true ? Does it have any merit ? The rear is a DANA 44a lsd

 

All the synthetic oils I have seen have weight ratings......

 

If you have a Dodge Ram, you do not have a Dana 44 rear end. If the mechanic that changed your rear dif fluid told you this, turn around and run!

I've never seen a oil that doesnt have a weight rating...except for canola, peanut, and vegtable.

 

No i have a 98 Jeep, but i brought this to a Dodge/Jeep Dealership. The mechanic told me he used synthetic gear oil that they use in all there vehicles and that it doesnt really have a weight rating.

Im wondering if he used a 75-90 oil and not the 75-140 i specificly asked for he also said he put 2 tubes of friction modifier. I heared putting too much like it seems he did will cause the LSD to not work right and be more like an open diff.

What do you guys suggest i do ? Change the oil again in the spring/summer cept buy the stuff myself, or leave it alone ? I've changed diff oil before i just didnt want to do this rear one cause they didnt sell 75-140 gear oil in shops where i live.

 

Look on your receipt, should give a part number for the fluids used. Call the dodge dealer parts department, and have them run the part numbers for you, and see what they are.

Some of the oil change guys we had in the chevy dealership were not exactly the brightest bulbs in the chandelier.......

 

Go to the dealer that you had it changed, ask the mechanic who changed the oil, and ask him to go grab a bottle of what he used in your Jeep.

And what was the dealer's name and location...Just so we know to stay the hell away from their service department.

 

Synthetics are made to mimic a standard oil, with whatever added benefits a synthetic purportedly has. A 75w90 synthetic is thinner than a 75w140. Both will work in our diffs, but a very knowledgeable shop in my area told me to use 75w140 due to the hotter summer weather in the south.

 

Well the mechanic who works there has 30 years experience the one who did this. There is no recipt because he did this on his off hours when the managers go home. Paid him $30 for the labor, the 2 head mechanics always work side Jobs after 6pm when people go home. My friend is the salesmen there so thats how i found out about this. Basicly they use Mopar or dealership tools/oils and charge me like $20-30 just for the work, and for the stuff that requires parts you just bring the parts and they do the work for cheap.

Had my brake caliper fixed, and brake pads and rotors done doing this, and had them replace a heavy leaking Neutral speed sensor on my tranny because i couldnt get it off.

Its just this diff change he did im not too sure about. He wouldnt really answer me on what weight he put in just that he put in synthetic and 2 tubes of friction modifier and told me to drive it for 50 miles to get it settled in. I wanted 75-140 because of the heat thing you just mentioned but he told me synthetic doesnt really have a weight and he used the mopar synthetic they put in all there Jeeps/dodge vehicles. I mean i know for sure he changed it because i checked the oil after and it was clear, and the old stuff was like rust color.

 

most likely they used whatever dodge gives them so it probably just say dodge axle lube on the bottle .it does have a weight rating and is likely whatever the factory recomends.honda gear oil is the same way it just says honda manual trans oil on the bottle and they wont tell you what the rating is cause its not listed.in other words they dont know.itll be fine if its factory recomended oil and friction additive.

 

The oil company I work for doesn't even blend and package a 75W140 in a GL-5 gear oil...for synthetic GL-5 we only make the 75W90..we also offer a 80,85W140, but it's not a synthetic...