E361T Brockway - 4.10's to 3.70's

[oldspwr]

Well it has been a pretty good summer for truck shows and the new 671 works really well. I went to Macungie, Honesdale, Cortland and finally our Harford show...



Now that I’m comfortable with the install I decided it was time to make a gear change. The truck was originally ordered with 4.10 gears and when I found the Neway air ride cutoff it also had 4.10 gears. With the 4.10 gears and 40.5” tall tires, I was right at 2200 rpm at 64mph or so. Since I want to have little room to breathe and get around somebody, I figured it would make sense to put a little taller gears in it.

I had asked a question on the Detroit group on FB about what the best cruising rpm is for a 2 stroke and received a ton of responses, from ‘slam your hand in the door’ nonsense to ‘keep it up tight against the governor at all times’. I finally received a couple of practical answers, including answers from Stan A and Joe D. They agreed that anywhere between 1900-2000 was a good cruising rpm for this motor.

I put a spreadsheet together and started running the numbers on the different ratios available for the Eaton 23105S rear, including the original 4.10’s, 3.90’s, 3.70’s and 3.58’s. After looking at the numbers I decided on 3.70’s which would put me right at 2000 rpm at 65 mph. I realize some guys like to run faster than that, but 65mph is a good speed for me. At that time I started looking for a pumpkin and wound up finding one at Global Truck Parts in Archbald, PA, not too far from home.

The rear came out of a Freightliner that supposedly had less that 200k miles on it and still had ‘shiny’ black paint. I was only interested in the pumpkin but it was a package deal so I took the entire housing...



I used the forklift to unload it and then tucked it in the garage to drain all the oil out of it and strip it down...





Once the oil was out of it I took it back outside and used a cup wire brush to clean it up...



After it was good and clean I used the cherry picker to pull the pumpkin from the housing and bring it back in the garage...



More to follow...

[oldspwr]

If you remember I wound up having to change the yoke on the original rear to go from 1810 series joints to 1710 series. Well this rear came with a 1760 series joint yoke so I planned on using the one from the 4.10’s. I was able to dig up the 1710 part number (6-4-9181-1X) and sure enough I found one on eBay. So I made an offer I was sure they were going to refuse and they wound up accepting it!!! I also found a brand new pinion seal on eBay for less than half of new so I bought that also.

With the new parts on their way, I set the rear up on a stand my Dad and I made when we rebuilt the 2 speed Eaton for the 155W. On a side note, can anyone guess what is in the wood box with the deluxe rubber tires???



Then I punch marked all the adjustment nuts for reference, measured the back lash, and then took everything apart...





And within a few hours I had everything stripped, cleaned, washed and ready to be reassembled. Fortunately all the bearings were either Timken or and made in the USA, and it very good condition.



Once the housing was empty, I took it outside and cleaned both the inside (and outside again) with the wire brush...



More to follow...

[Huskiedrive2]

Nice work Tom. 3.70 on 20" rubber is a good choice.
As for the crate on deluxe rubber wheels, I'd guess a Sheppard power steering box. It's the only thing I can think of that's really heavy in that small of a crate.

[oldspwr]

Hi Stan, you are correct! I made the wood box when I shipped my Sheppard 592 box back to the factory in Hanover to be gone through. My Brother showed up one day with the wheels from an old hose reel and I thought they would make it a alot easier to move around the garage. More updates to follow...

Tom

[stubnosebrock]

I agree, 3.70 sounds about right. If you wanted more road speed or lower RPM more, id consider an overdrive before more rear gear. My Huskirdrive truck would do around 72mph if I remember right, in direct, with 22.5s

[oldspwr]

Thanks guys... here are a few more updates...

Once everything was good and clean I started reassembling everything...



And I had to find some creative ways to torque the bolts in the carrier...



Then I dug out a piece of 1 1/2" square stock I had used for the 2 speed, and used this to set the carrier back in the housing...



Once I was done with the carrier, I moved back to the pinion support. After I reassembled it I checked the pinion preload and realized I it was too loose. Per the manual, I was using the press method with a spring scale to check the preload instead of installing the yoke and tightening it up every time...



More to follow...

[oldspwr]

To get the preload correct I had to take several thousandths off of the bearing spacer. The space was a little of a half an inch thick to start with.



Once I was happy with the preload I made a seal installer from a piece of wood...





And then I took a 4” wide piece of 3/16” flat stock and drilled holes to mount the new 1710 yoke in it. I actually used the other side of the one I made for the 2 speed. This would allow me to bolt the pinion in the vice and torque the pinion nut (830 ft lbs)





I was able to recruit Tommy this time to help me torque the pinion nut. It’s hard to see in the pic, but I tied a 2” strap around the pinion cage and the vice, just in case the vice broke. If the pinion hit the concrete it would not be good!!!



More to follow...

[oldspwr]

I installed the pinion cage and then reset the gears to exactly where they were before I disassembled everything. I made several small changes, double checked the pattern and made sure the back lash was very close to where it was...



Once I was comfortable with everything, I taped it up and took it outside to paint it, along with the Saginaw steering box for my Brother’s 81 pickup...









I usually wait a week after I paint anything before I install it, so I decided to chase another problem I had. I originally had temp gauges for both the rear and trans. Both gauges started at 140 degrees and never moved. I wound up buying two regular oil temperature gauges that started at 100 degrees. The trans would get up to 150-160 deg or so but the rear would never move. Using a meter I realized the rear was not really grounded well. Without a good ground, the gauge would not get the correct resistance reading from the sending unit. So I would up buying a ground bar clamp from the hardware store. I had to file the one side so that it would clamp well around the bushing for the sending unit. Then I ran a wire from the ground bar clamp directly to the frame...



This did the trick... I took the truck for a good ride (with the 4.10’s) and the gauge climbed just a little over 120 deg. I wanted to have a basis of comparison for when I changed the gears. The trans is on the left and the rear is on the right...



That's it for now...

[Huskiedrive2]

Very good Tom! If you want to see those gauges climb, hook onto one of Joe D's trailers and pull a load somewhere. If you get some resistance instead of free rolling, the rear (and tranny) will make some real heat!