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Author Topic:   Rear End Oil
Dirt Newbie

Total posts: 4
posted April 06, 2005 10:37 PM  
What is the best to run? Have chewed up 4 different sets all set up by different pro's, and using different carriers each time. Have been using Mystic JT7. Hookin' up hard with about 615 hp. 20 lap features 1/2 mile track. Tightens up like the brakes are on after about 12 laps.

Dirt Forum Champ
Total posts: 874
posted April 06, 2005 10:44 PM  
I've only used Red-Line Shock Proof, we've used it in all of our cars. It'll run ya 40 bux for a gallon, but you can re-use it over and over again

Dirt Forum Champ
Total posts: 2007
posted April 07, 2005 07:38 AM  
WE have been using Synergyn for the past few years, and havent had any problems. Never had problems with regular old gear oil either.

Dirt Freak

Total posts: 270
posted April 07, 2005 08:21 AM  
Another question is how much gear oil are you using when you fill it. If you use a Seals-it right side axle tube seal you can get away with a 1/2 gal min. It will keep all the oil from running into the right side tube starving the gear set. Run a full gallon to be safe. Most builders tell you to run a gallon anyway. We use Redline HD shockproof and we also re-use it. Run it thru a paint strainer to filter it.

[This message has been edited by Dman (edited April 07, 2005).]

Dirt Forum Champ
Total posts: 2007
posted April 07, 2005 08:46 AM  
I would think if you are having that much trouble with tearing gears up there must be something else wrong besides the brand of oil. Possibly even the quality of the gear itself. Make sure you have heavy enough oil and most important have enough oil in the case. Here is a link to the oil we use.

We use 3 1/2 to 4 qts even with the axle seals. And we do reuse and strain it through a mesh screen in the funnel when pouring it back in. We have run the same gear set for 3-4 years 20-25 nights per year with no problems and no appreciable wear, no matter what oil we were using.

[This message has been edited by dirtbuster (edited April 07, 2005).]

Dirt Roller

Total posts: 24
posted April 07, 2005 12:01 PM  
We have run them all. The best is Redline Heavy Wieght Shock Proof.It runs the rear end cooler and I can run a set of gears for two seasons easy.

Dirt Full Roller

Total posts: 73
posted April 07, 2005 02:29 PM  
Axle problem possibly??? I haven't burned up 4 gear sets ever, and I just use regular 90 weight with about the same amount of hp's and about 7500 rpm. Fill it up until it leaks out of the top.

Dirt Maniac

Total posts: 180
posted April 07, 2005 09:40 PM  
We use Amsoil full Synthetic 75w90, and reuse it. Gears run cooler than with regular gear oil. The Mystic oil is cheaper, and might not be high quality enough. If you have lost that many gear sets, it's probably not an oil problem. When the gears go out, are the bearings locked up, or are the ring and pinion just chewed up?
Do your gears generate alot of heat after only a short run? Try checking them with a laser temp guage. My housing is usually around 100 degrees after a 15-20 lap run.

James Birmingham
Dirt Full Roller

Total posts: 28
posted April 08, 2005 06:51 AM  
Sounds like the bearing are going first if it "tightens up like the brakes". Are you run a solid spacer or a crush sleeve? If you are having "Pro's" set them up are you changing yokes after they are done. I had a guy burn up 2 sets I had built because they were hammering the same yoke on each of them. Spacers are the only way to go. Your not having the drive shaft bottoming out are you?

This is related to another subject in the forum also. I had a buddy with a bad engine ground that was grounding through the drive shaft and it was burning the bearing out.

Dirt Forum Champ
Total posts: 796
posted April 08, 2005 11:54 AM  
Have you identified the failure yet? If not i would find out, or try to find out what exactley is failing first.

Last year we ruined a chunk due to the drive shaft bottoming out, took a couple races because it wasnt hitting all the time, just on extreme rear steer.

None the less it caused the failure. Check to make sure your driveshaft is not bottoming out against the tranny on extreme rear steer conditions.

If the pinion bearing area is failing, i would bet thats the case, or over torquing.

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