Hey guys,

I have some new parts coming in.

Summit 3:73's
Eaton TrueTrac LS
Full Rebuild Kit
Trick Flow Rear End Cover

This SHOULD all be here tomorrow, so hopefully I can have it installed this week.

Question:

What is the best procedure for break in?

Ive read a few people saying 'just dont drive for more the 30 minutes for the first 500 miles'.

And others that were much more specific.

I have not been able to find anything that sounded like something everyone agreed on.

My problem is that if I can only drive 30 min at a time for the first 500 miles, I will have to wait a while to put these in...

Also, how long would I need to wait before I could start towing with the truck?

Any other input is greatly appreciated.

Thanks,

-Dennis
____________

 

my gear sets stated 30 min max first run. then no towing for 500 miles then dump oil

 

Thanks man!

 

You shouldn't drive more than 10-20 minutes at first. Drive 15 miles to let the gears warm up, park for at least 30 and let them cool down. Repeat that a time or two. Don't tow for the first 500 miles.
After 500 miles you should pull the cover, check for anything unusual and re-fill with new oil.

 

1. Insure that the axle has been filled to the correct level with
proper hypoid lubricant before driving the vehicle.
The oil rating must be GL5 or higher.

2. Bring the axle to normal operating temperature by driving the
vehicle (unloaded) for approximately 15 to 20 miles. Do not
run full throttle accelerations or create any shock loads.

3. Let the axle assembly cool completely.

4. For the next 200 miles of operation, drive gently, without any
heavy loads.

5. If trailer towing is intended, an additional cycle of 200 to 300
miles of break-in is required without the trailer. This is important!
To properly break-in a new gear set, a minimum of 500 miles of
driving is essential before towing.

 

I think Yukon gears said that they werent broke in until you did the 500 mile thing, then towed for appx 15 miles, stop, then another 15, stop, and one more run and stop (bringing you appx 3 stops within 50 miles). If I remember what I read.

 

Thanks fellas, I cant wait to get this project goin!

 

the other tech info was from PG

this is from Yukon

New Gear Break-In
All new gear sets require a break-in period to prevent overheating damage. Any overloading or overheating will break down the gear oil, which will cause the ring and pinion to fail.

This can be determined by inspection and will void the gears’ warranty.
Please follow these guidelines to insure proper break-in.
1. Avoid heavy acceleration during the break-in process.
2. Drive the vehicle lightly for the first 15 to 20 miles and stop. Let the differential cool before proceeding.
3. Avoid heavy acceleration for the first 100 miles.
4. Drive the vehicle at least 500 miles before towing to retain the gears warranty.
5. When towing for the first time, drive for a very short distances (less than 15 miles) with the full load and stop. Let the differential cool for about 20 minutes before proceeding. Repeat this procedure two more times (45 miles total) to fully break in the gears.
6. Change the oil after the first 500 miles. This will remove any metal particles and phosphoric coating shed by the gear set during the gears’ break-in period.
These towing instructions may seem unnecessary to most people, but we have seen many differentials damaged from being loaded before the gear set was fully broken-in.

 

Thank you, that answers some questions i had.

So, I plan on getting these put in next Wednesday. However, I am leaving to drive from Dallas to Houston (about a 3-4 hour trip) on thursday afternoon.

IF I can put the first 50 miles on them on Wednesday after I have them installed, is it safe to drive to houston on Thursday if I take it slowly and I guess pull over every hour or so for the gears to cool down.

Im only asking this because this trip could knock out the break in process and I would be good to go. But if it cannot be done ill have to wait.

What do you all think?

 

This is the same situation I found myself in during my gear install. My installer was 700kms from my house. I drove down, had the gears installed, and spent the next day driving around town, heating and cooling my new gears. On the trip back home, I did the same thing, stopping about every half hour to check the rear end temps, and to let them cool if the felt hot to the bare hand. Once I made it back home, I had put on around 500 miles, and it was time to change the oil. No issues so far.....

 

The instructions basically say drive 10 -15 miles at a time for the first 50 miles with 30 min stops in between...then just drive lightly for the next 450 miles. 500 = oil change. Then break them in with the trailer.

So... I WOULD be okay to make this trip if I stopped every hour or so? Sorry if Im being annoying here guys, I just really want to do this right.

Also, I plan on using Motorcraft 75w140 in the new rear end, can I use this same oil during the break in process or should I use something else?

Thanks again.

-Dennis

 

Got the parts in!!

 

Well it looks like the truck is going in the shop Wednesday! Im excited!

Im just hoping that my trip to houston the next day will be okay on the new gears. I plan on stopping every hour to let them cool down.

 

Hmm thats the tru-trac eh?

I remember getting my locker, then planting it in the middle of the kitchen table for a few hours while the family ate dinner.

 

Yea, I stared at mine on the table till the wife got home and said "what the hell is that on my table".