450c trans problem

[Bobby H.]

I am having a problem losing pull when going uphill (falls out of gear) in low range unless the trans is over the full mark on dipstick. High range feels like it goes into gear but is slipping. Has anyone had problems with pickup tube in trans for the pump. Trans fluid, filter has been cleaned twice. I need to check pressures again. Just concerned because of overfilling to make work in low range.

[BigMac61]

You say you have changed the filter. I assume that you are referring to the filter that is located in front of the radiator? Have you also checked the screen/filter located at the bottom of the transmission? This filter is often overlooked and can be clogged with debris from worn clutch plates which will sometimes give insight as to what is going on.

[Bobby H.]

Yes I did clean the filter screen in bottom, twice. Some debris but not what I would be concerned with. I have no been into the trans so I didn't know if anyone has had trouble with pickup tubes maybe sucking air when dipstick shows full like when the level is low. This machine sat for many years before I got it and I don't have much history on it. Had to work the tranny a Lot back and forth change fluid filters and clean screen several times before it started working. It maybe a retirement project . Looks like an automotive type automatic trans so that shouldn't be any big deal, just bigger nuts and bolts.

[BigMac61]

Ok, do you have the service manual for that dozer? It should be TM1102. If so have you been through the adjustment procedure in the exact order as described in the manual. Also I would get a pressure gauge setup and check/monitor the pressures while moving the the reverser lever from high, low, neutral and reverse and see if you are losing pressure and when. The screen at the bottom of the transmission is the return for the transmission oil. The other question I have is why is the transmission oil dropping? Are you losing oil somewhere? I have not heard of an issue with the pickup tube from the transmission sump but in these old dozers anything is possible. Sorry for all the questions but I’m just trying to get a complete picture of what is happening since I am not there to look at the machine.

[Bobby H.]

Yes I do have service and parts manuals. It has been awhile since I checked and adjusted pressures. High has never been real strong ( I've owned about 10 y rs) and I don't sue very much so I have been good with just having low . It will be several weeks or a month before I can get time to recheck pressures. I am loosing some fluid at controls for bucket and ripper. I am glad for any feedback. questions are always good , helps with getting educated solution . It seems very hard to do zoom calls with no phone reception
stuff has not worked in my favor so pressures have not been check due to broken final drive bolts . pulling tracks final drive broken bolts and replacing rollers before I get around to checking pressures.