Synth Oil In Rear Diff

Nytemare · January 30, 2009

I have about 60k miles on the truck now...you think if I switched to royal purple in the diff the seals would start leaking? I heard a while back someone saying that the seals aren't great to begin with...

What you guys think?

C & A s Dad · January 30, 2009

Your truck has Syn gear oil from the factory. Changing it to RP or any other syn will not make it leak if it is not leaking now.

I am not slamming RP but I would suggest you look at Amsoil Severe Duty gear oil if you do any towing at all.

Z45 · January 30, 2009

The seal leaking tale is a big myth spread around the internet. If its not leaking now, its should not leak if you change oil.

Spurshot · January 30, 2009

When was the last time someone wore out a diff? I've put near half a million miles on a little 7.5" GM diff with a series of low to high output engines in front of it from about 200 to 400 hp using Sta-Lube standard gear oil (in a open diff). My 99 2500 GMT800 has 213,000 miles on it and it had the factory gear oil in it until this last summer. I towed one season of horse trailers up to about 8000 lbs.

Nytemare · January 31, 2009

well the only reason I wanted to change it out was to get more HP, as RP adds HP OK seriously, I really do like their product, I have it in the engine and Trans, and noticed a change in operating Temp, Trans shifts smoother, but that could just be due to the new filter. I also want to pop the cover off and have a look inside at the gearset to make sure nothing is getting abnormal wear and I figured that I'd keep with the theme and put RP in there too, I have it already, was just afraid to put it in from the "myth" of the leaking seals. But It looks like I have something to do on the weekend now.

I would try the Amsoil, but I don't really tow anything, and if I do it will be most likely just be my LJ80...Hell I dont even have a trailer hitch on it...LOL

cbxeric · January 31, 2009

I just changed mine at 300,000km, the old oil still looked new. no leaks either. I put in good old Motomaster synthetic 75w90 front and rear.

ColoradoSkiCountry · January 31, 2009

90,000 miles on my old 99 Silverado G-80 diff. It too had synthetic. The thing blew apart. The Synthetic did not make a bit of difference, though on those without the G-80 I'm sure it might do some good.

ScottyBoy · January 31, 2009

When was the last time someone wore out a diff? I've put near half a million miles on a little 7.5" GM diff with a series of low to high output engines in front of it from about 200 to 400 hp using Sta-Lube standard gear oil (in a open diff). My 99 2500 GMT800 has 213,000 miles on it and it had the factory gear oil in it until this last summer. I towed one season of horse trailers up to about 8000 lbs.

The rear end in my Suburban went out at less than 80,000 miles. I have an 01 with the 5.3 engine and 3.73 gears. They said all the ring and pinion gears and bearings and all were shot. I brought it in simply because it was making a clunking sound. I thought maybe I had a bad suspension bushing or something. But luckily my extended warranty covered the cost. They were kinda hesitant at first, being that the rear end was shot at less than 100,00 miles. They even sent an adjuster from Houston to personally inspect the damage, and they ended up paying for everything. I don't do any heavy towing, all I tow is a utility trailer with my yamaha grizzly 4 wheeler on it. They said its possible too much togue weight could have caused it to go out, but even if ALL the weight of my 4 wheeler was on the tongue, thats still only about 600 lbs, which is the max tongue weight.

Spurshot · January 31, 2009

When was the last time someone wore out a diff? I've put near half a million miles on a little 7.5" GM diff with a series of low to high output engines in front of it from about 200 to 400 hp using Sta-Lube standard gear oil (in a open diff). My 99 2500 GMT800 has 213,000 miles on it and it had the factory gear oil in it until this last summer. I towed one season of horse trailers up to about 8000 lbs.

The rear end in my Suburban went out at less than 80,000 miles. I have an 01 with the 5.3 engine and 3.73 gears. They said all the ring and pinion gears and bearings and all were shot. I brought it in simply because it was making a clunking sound. I thought maybe I had a bad suspension bushing or something. But luckily my extended warranty covered the cost. They were kinda hesitant at first, being that the rear end was shot at less than 100,00 miles. They even sent an adjuster from Houston to personally inspect the damage, and they ended up paying for everything. I don't do any heavy towing, all I tow is a utility trailer with my yamaha grizzly 4 wheeler on it. They said its possible too much togue weight could have caused it to go out, but even if ALL the weight of my 4 wheeler was on the tongue, thats still only about 600 lbs, which is the max tongue weight.

Scott,

Sorry about you bad experience. Sounds like they were scratchin for traction for a "cause". I'm betting it was an anomoly and not all that common, hpefully.

6chevelle9 · February 17, 2009

When was the last time someone wore out a diff? I've put near half a million miles on a little 7.5" GM diff with a series of low to high output engines in front of it from about 200 to 400 hp using Sta-Lube standard gear oil (in a open diff). My 99 2500 GMT800 has 213,000 miles on it and it had the factory gear oil in it until this last summer. I towed one season of horse trailers up to about 8000 lbs.

The rear end in my Suburban went out at less than 80,000 miles. I have an 01 with the 5.3 engine and 3.73 gears. They said all the ring and pinion gears and bearings and all were shot. I brought it in simply because it was making a clunking sound. I thought maybe I had a bad suspension bushing or something. But luckily my extended warranty covered the cost. They were kinda hesitant at first, being that the rear end was shot at less than 100,00 miles. They even sent an adjuster from Houston to personally inspect the damage, and they ended up paying for everything. I don't do any heavy towing, all I tow is a utility trailer with my yamaha grizzly 4 wheeler on it. They said its possible too much togue weight could have caused it to go out, but even if ALL the weight of my 4 wheeler was on the tongue, thats still only about 600 lbs, which is the max tongue weight.

Scott,

Sorry about you bad experience. Sounds like they were scratchin for traction for a "cause". I'm betting it was an anomoly and not all that common, hpefully.

Question for you guys , I have 05 GMC Diesel, I want to change the rearend fluids and Transfer case fluids.. I use AMSOIL for the motor. What you guys think ? Are there special additives needed for the rearend/front diff ? Thanks Joe

Valvetrain · May 16, 2009

I blew my diff out two years ago. The pin shot out through the cover. Granted it was snowing and cold out but non less it blew.

Alljackedup408 · May 17, 2009

JFK1, yeah i run amsoil all throughout my truck.. its from head to toe.. and everything works A ok! do it!

ColoradoSkiCountry · May 19, 2009

Amsoil won't make a dang bit of difference in the G80, when they go, they go. no matter what type of oil you ran.

vertikal · May 30, 2009

When was the last time someone wore out a diff? I've put near half a million miles on a little 7.5" GM diff with a series of low to high output engines in front of it from about 200 to 400 hp using Sta-Lube standard gear oil (in a open diff). My 99 2500 GMT800 has 213,000 miles on it and it had the factory gear oil in it until this last summer. I towed one season of horse trailers up to about 8000 lbs.

Ive a 2004 quadsteer 2500lt chevy w/3.73 gears and worried about diff...may install 4.10 ratio in front and rear as I tow a 10,000 lb fifthwheel

Irv · June 2, 2009

I am a big fan of Mobil-1 products including their 75-90 Diff fluid.

I replaced the gear oil in both diffs in my last truck (97 Sierra Z-71) and never had a problem up to 160,000 km's, that is pulling a boat, sleds and atv's during the right season. When the time comes on my new truck (5000km's) that is what is going in this new truck.

Not a big fan of Amsoil (personal reasons/experiences)