Hi everyone.
Today I noticed that my drop box was dripping oil after driving it and found that all of the bolts holding the input shaft cover and shims was loose. No bueno! The drop box is tight to the differential and no issue there.
What's a good way to take care of this? Can I just tighten up (re-torque) the bolts again and be done with it? If I did that, should I remove the cover and shims and clean all of the surfaces up? I had read that a bad bearing can make the bolts loosen - should I be pulling out the input shaft/gear/bearings and having someone inspect the bearings? Is it difficult to get the shaft/gear/bearings out?
If the latter, and I end up getting new bearings, is there anything else I would need? Is it difficult to get the shims just right (never done that before, so I'm asking). Should I dump and refill the drop box and differential oil just in case?
Thanks. Any words of wisdom and recommendations are welcome. We're hoping to get back on the road next week...
Check closely for worn or bad u-joints- vibrations
Kitt,you need to pull the drop box and replace all 4 bearings Jefferson has the new shim packs and gaskets the bearing need to pre loaded and the end play on the input shaft needs to be .001 to .005 they are close some time the inner bearing race need to be shimmed out to achieve it
Not a hard job to rebuild the drop box on a Eagle but they need to be right or they will come back to haunt :o
I ended up taking the bus to a shop and bought all of the parts (bearings, shims, gaskets) from Jefferson and got them over there. I went over there today to see it and they showed me the input shaft (#13 in the parts book, Rockwell 3280-S-4622) and a bunch of the threads in the middle of the threaded area are loose - meaning that the threads are there and contiguous but at a certain point they're no longer part of the shaft, if that makes sense - probably near where the bolt was that held the end yoke on. My best guess is that the shop that put the HT740 on for the previous owner, along with the new driveshaft, didn't do something right. No issues were found with the drive shaft. The good news is, at least, is that the old bearings seemed good and there was no metal in the oil.
The shop is trying to find a new input shaft (from Jefferson and other sources), but I figured I would ask here if anyone has one they'd part with... Also, if anyone has a sketch or write-up on how their drop box was set up with the new yoke end and drive shaft for a 740 that may be helpful if we/they need to redo what was done before.
Sad they left the thrust washer out behind the yoke I'll check my stash I may have one but these MCI guys have been killing me on drop box parts
I know Gary at B&B in Vegas will have a used one he has drop boxes scattered all over the place give him a call first, the price of the shaft and washer at Jefferson will give you the big one lol the washer cost 55 bucks
Thanks, Clifford. I think there may have been a thrust washer in there (that must have been the other part they showed me that I don't see in the parts book) but it was pretty scratched up, so that'll need to be replaced for sure. I'll check with Gary.
The shop used 70w90 synthetic in the drop box and rear differential but there is some seeping from where the metal shins are. The shims were new and everything was cleaned and torqued correctly. What are some of the common issues and what's the best way to fix the seeping? Should they be using a straight 90w oil instead?
Clifford, I better check the drop box on my GMC for looseness. Oh wait, I don't have one. ;D
The drop box and differential are supposed to be 85/140w the shims will seep for a while just check for tightness again,there are 2 holes in the rear of the box that require bolts if something is not attached in that spot and the drop box use flat steel washers not lock washer with lock washers they seep
Some Loctite sealant would be good to use on those bolts.
My manual said EP90w, but we will do the 85/140 - they just have to order some. Thank you!
Hum my manual says 75/90 below 10 degrees 85/140 above 10 degrees it's a model 15 manual but the drop box and differential are the same
Ok, that makes sense. It's cold up here now, but I don't plan on hanging around in this cold too long or driving much when it is below 10, so we're going with the 85/140.
Cliff, about 7,000 or so miles into our trip I noticed the input cover loose again. I retorqued all of the bolts to 60 ft-lbs and drove another 3,000 miles and didn't notice any issue. Any thoughts on what could have caused this a second time? Anything I should look into (hard shift? Motor mounts?)
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Quote from: luvrbus on December 05, 2014, 06:52:59 PM
Sad they left the thrust washer out behind the yoke. I'll check my stash I may have one, but these MCI guys have been killing me on drop box parts.
Clifford -Is the drop box in my MC-5C the same one that Eagle used? According to my Final Vehicle Record, I've got a Rockwell R164-WX37 rear axle.
TIA,
RJ
Same drop box RJ they interchange no problems but the rear axle is different the Eagle has lager axles,cage and spider gears I guess because it was a 40ft 3 axle bus
So the idea I had about putting a 3.38:1 pumpkin & drop box out of an Eagle won't work, except for the drop box, eh?
Darn. . .
:(
What do you have in there now RJ? On my 5A the 3.36 was standard and the 3.7 was optional.
I bet he has the standard 4:11 with the 6V71 same as JC had before he went to the 3:36
I bet you are right, the 5C with the 6v71 was a different animal. ;D I wonder why they went with that instead of the 8v71.
Quote from: Ed Hackenbruch on June 25, 2015, 06:54:56 AM
I bet you are right, the 5C with the 6v71 was a different animal. ;D I wonder why they went with that instead of the 8v71.
Ed -Yes, my 5C has the 4.11:1 rear end.
Apparently, back when the coach was new, if you ordered a 5C with an automatic, you got the 6V71/MT644 combination with a 4.11 rear end. If you didn't order the automatic, you got an 8V71/8844 Spicer with a 3.7:1 final drive. At the time, it was "space considerations" that they gave as the reason. Also, from what I've been able to gather, the majority of non-Saudi 5Cs were ordered by operators doing airport shuttle service, not long-haul revenue or charter work. Thus the more transit-like gearing.
I'd like to find a 3.36:1 rear pumpkin that would fit. I've got a 6V92TA/HT754 powertrain available to me for a VERY reasonable sum, so the 3.36 would be ideal.
RJ
RJ I heard there were a lot of 3:36 for MCI in Canada ask Joe on the BNO he knew of several last year for something like 600 bucks ea
my coach has the 333-1 on the pumpkin and would love to have the ht 754 and found 1 but never could find the electronics for it that are missing :(
dave
I was told the rear in my 5C came from an Eagle,3.36. I wish now I had the 4.11 back as I changed from the 740 to a Allison 6 speed. Only programed for 5 speed now with the 3.36.
When I swapped the 4:11 for a 3:36, I replaced the ring and pinion gears. I didn't remove the rear axle carrier and pumpkin. I got the 3:36 guts from a charter operator near Red Deer AB. I paid a lot more than $600. Like around $2500 IIRC. Including a spare drop box. Worth every dollar though. I still have the 4:11 gears if anyone is interested.
I remember at Brewster's in 1977 getting several new 5Cs with the 6V71 and automatic. They were slow and sluggish. A shame, because they were such a nice bus otherwise. But they were only used locally, not for charters or anything long distance. They didn't have bathrooms either. We used 5As and Bs with the 8V71 and 4 speed Spicer for that. Also MC7s and 8s, which were all fairly late models then.
JC
I checked with my gear supplier in Houston he tells me $2180.57 plus shipping is the best he can do on a 3:36 ring gear and pinion with bearings for the MCI 5 last one I purchased one 6 years ago cost $1400.00 with shipping.
I would check with Joe he told me on the phone he knew of a couple about 50 miles from him I was just after the drop boxes.Only Eagles I knew of using the 3:38 was the model 15 fwiw
Does the drop box cover have any alignment dowels? They usually help control cover movement. Also after torquing with either Loctite or wire the bolt heads. if no dowels, you could install 2 or more studs in place of bolts to control movement.
The problem with the drop boxes are the shims are the gasket once you get it tight they don't leak unless someone decided to use the RTV silicone or it has a bearing problem or a drive shaft problem if the nut is not torqued on the yoke and input shaft it will loosen the 3/8 bolts also
I'm wondering if the threads in the case are worn/loose. That would allow the tension to relax and the bolts will back off some. You can clean the threads with brakeclean and blow them dry. Try the green or blue loctite with some new bolts. Let it set overnight if possible.
You can use "gasket eliminator" on those shims. It is designed for use in joints without a gasket/seal. It is very thin and will stop the seeping. You just need a single bead, No need to paint the entire shim. I know CAT sells it, Detroit uses it on the S60 and others
Maybe the driveshaft should be checked or balanced by a shop that does it and ujoints could be worn from many miles and look good otherwise. On a large vehicle, vibrations may be not as noticeable or be blamed or incorrectly attributed to tires.
any anaerobic sealant/gasket eliminator is better than sillycone. I hate that stuff. I've dug so much of that crap out of suction screens.
Lube pump suction screen in a differential is a very costly place to find it.