I have a 450c case dozer that operates great when cold. Once the fluids get up to temp the left track hesitates when shifting both the hi/lo and direction levers. In doing research I seen where other Case dozers have a seal that bypasses oil and causes this issue but my manual does not make this clear so any advice would help. Btw after the trans does engage there is no slipping and it pulls strong, it just takes a few secs to engage.
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Case 450c hesitates shifting when warm?
- Thread starter utvol
- Start date
Are you referring to the sealing rings on the pto shaft? I had to replace them on my 850c, there's 3 of them and I made and installed a sleeve to go in the housing. Should be a tube cover on the back with two lines going into the top of it. The pto shaft and sealing rings are in there.
From what I gather it is the shaft that the hi/lo clutches are on. There is a cover right behind brake assembly that has two hoses going to it. Seals start to bypass and pressure goes to hi and lo causing problems? Problem is the cover will not come off because there is not enough clearance between the brake assembly? Is this making any sense? Did you have to remove your brake housings? Thanks for the help Rickdavis.
The PTO shaft sealing rings (3) there are for the forward and reverse clutch packs.
The track speed clutch packs Hi & Lo, RH side & LH side, have sealing rings on the front of the transmission right behind the brake housings. There are 2 metal hook type seal rings in the clutch shafts sticking through the tranny front cover. The shaft end/seal rings are covered by a cast iron cap with 2 hoses coming from the tranny control valve sitting right on top of the tranny.
To replace the F/R (3) seal rings on the PTO shaft is fairly easy, it's all on the back.
The (4) two on ea. side behind brake housings and carriers is a major pain.
The track speed clutch packs Hi & Lo, RH side & LH side, have sealing rings on the front of the transmission right behind the brake housings. There are 2 metal hook type seal rings in the clutch shafts sticking through the tranny front cover. The shaft end/seal rings are covered by a cast iron cap with 2 hoses coming from the tranny control valve sitting right on top of the tranny.
To replace the F/R (3) seal rings on the PTO shaft is fairly easy, it's all on the back.
The (4) two on ea. side behind brake housings and carriers is a major pain.
I was starting with the hi/ lo on the front and yes brother you are right, major pain! I got the hoses off and the four bolts out of the cap but the cap will not come off the shaft as there is not enough clearance between brake housing. If I take the cap off of the rear can I slide that shaft back just enough to clear the front cap? I do not want to take those brake housings off of I can help it.
1978 case I just realized, are the caps on the rear not just the back side of the hi/ lo shaft on the front? I have a ripper that I have to take off to even access the rear caps but it looked like they lined up with the front caps that I have the bolts out of? If the hi/ lo shafts do not have caps on the rear then I guess I have no choice but to pull the brake housings so if that is the case how big of a job is that? What few people I have seen on here replace those seals didn't seem to have this clearance problem of getting those caps off, but there is only 1/2 in. clearance between the caps and brake housings on my machine. Am I missing something? Thanks for the help!
Nothing you can do for the Hi/Lo seal rings from the rear. The rear covers just cover the rear of the shaft/ bearings. The only way is to remove the brake housing and then the carrier. A tight spot for sure! The seal rings can be the source of leakage but so can the clutch drum seals.
The brake housings are held on with 3 bolts. Remove brake lines and PB cable, then the 3 bolts that secure the housing and take it out, no need to remove the slave cyl or return spring, leave em on the housing. The carrier (the part that's in your way) is attached to the front cover can be removed. The carrier has a oil seal where the spline shaft sticks through. You will also find shims and a rubber seal where the carrier mounts to the front cover. After you get all that mess out of the way, you can easily remove the caps and replace the seal rings. Also inspect the inside of the cap for wear/grooves.
The brake housings are held on with 3 bolts. Remove brake lines and PB cable, then the 3 bolts that secure the housing and take it out, no need to remove the slave cyl or return spring, leave em on the housing. The carrier (the part that's in your way) is attached to the front cover can be removed. The carrier has a oil seal where the spline shaft sticks through. You will also find shims and a rubber seal where the carrier mounts to the front cover. After you get all that mess out of the way, you can easily remove the caps and replace the seal rings. Also inspect the inside of the cap for wear/grooves.
Thanks alot 1978Case. I knew I couldn't get to the seals from the back i was just hoping with the rear cap off i could slide the shaft a couple inces to the rear so the front cap would clear, or if the shaft was locked in place with snap rings. I'm not looking forward to standing on my head taking those brakes off but I don't have much choice now. As you mentioned above is there a way to determine which seals are likely the issue? While I'm in this far I want to make sure I have it resolved. Your a lifesaver nobody else seems to know much about these old dozers.
alrman
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The reason other posts mention removing the front end caps, is because they are likely 1150's which are configured differently to allow that to happen easily.
If you are pulling the brakes on a 450C, I would recommend raising the machine off the ground, putting solid timbers under it, removing the belly pans, giving it a good pressure wash.
You can do most of the job from underneath, some from above - & you'll find it much more comfortable.
If you are pulling the brakes on a 450C, I would recommend raising the machine off the ground, putting solid timbers under it, removing the belly pans, giving it a good pressure wash.
You can do most of the job from underneath, some from above - & you'll find it much more comfortable.
The problem is in both hi and lo on one side only, so the leakage would be between the control valve and the clutch drum pistons most likely. The control valves were pretty much trouble free in my experience. I remember an internal retaining ring on a track hi/lo control valve spool broke. The spool is a two-piece assembly, the rear of the spool; directs the oil and the front part is for the 3-position detent. If the internal retainer fails, the rear oil directing spool will be left in the hi position (pushed into the control valve body). The front detent part will work and feel like normal but will not pull the spool forward out of the valve body leaving the hi-speed clutch charged.
I would think if the problem was a clutch piston seal it would be either hi or lo but both clutch packs are weak? Let's hope it's not internal! That would bean pulling the tranny. You can't get the front cover off with it in the frame.
Good advice here.
Not to make this even more complicated the left track "problematic track" feels like it has no detent. The spool glides in fw/n/rv with little to no detent. I assumed the detent spring was seized or broken. Because it does fuction great until fluid gets warm I was thinking the actual spool is functioning and the leakage is clutch seals. The detent seems to be adjusted to the same as others but I was going to look into that spring before going back together. Am I seeing the parts diagram correctly that they're are no internal seals in the control valves? That is where my mind went first because of the way that spool feels but I seen nothing to replace. I'm about to start removing the brake assembly and hope it's not for nothing lol. Thanks again guys. Btw I could only find those seals at a couple of places and they were $50 each! Other people acted like they were just a few bucks and to buy extras lol. Did they change the seals on the C's or are they different on 1150's or something? Makes me question whether I have the correct seals coming?
And 1978case just to make sure I answered your question none of the clutches seem weak per say, there is just a delay in the left track engaging once shifted... and only when it is warm. Once it does engage it pushes strong. When cold the speed and direction changes are instant like the right track.
The detent holds the spool in the correct position so that could be a problem. These old trannies had a lot of leakage built right in. As the oil temp rises it does'nt help that leakage any either. I would fix that detent issue for sure; you are right the only spool seals are the ones for the front plate that holds the detents where the spools stick out. The 1150 and bigger have a different tranny. $50 a ring DANG. Tre Hagen salvage in Coweta, Ok. I used to get a lot of aftermarket there.