So wrench benders, I'm lookin at a cat d4h 8pb030xx that is missin 3rd completely, both foreward & reverse, however, all other gears behave normally. Machine was used in the woods, possibly for skidding. I've had the machine on slopes in all directions and horsed around a little, no clanking or banging, just no third. Whats my chances that the 3rd gear clutches are whipped, and thats my problem?
First thing is make sure the linkages are not worn. If so you aren't moving the speed selection spool far enough. Clutch #3 is the common clutch for 3rd gear both forward and reverse, P1 should be 370psi at high idle in gear.
Does the transmission oil smell burnt..? Pull the pump suction screen and maybe also the filter. Can you see either large quantities of clutch facing material or maybe a few pieces of what might have been a clutch piston seal..? If not ........ ....... Check the shift linkage. It has more ball joints in it than a donkey's hind leg. Do you have a combination of wear in some of those that is preventing the transmission control valve direction spool from moving far enough to select 3rd gear..? Hook up a 5-600psi gauge on the P1 test port of the transmission. Start the engine and stall the transmission in 1st gear, then shift to 2nd, then to 3rd. As you shift you should see the gauge dip slightly then return back to the pressure it was before. If you don't see it dip during the shift between 2nd & 3rd I'd say something (most likely wear) in the shift linkage is preventing the shift to 3rd speed.
No the tranny fluid doesn't smell burnt, and its been in there awhile... We will see if i get it, but if I do a full fluids & filter change is in order.
Stumpjumper if when hot at normal operating tempature first and second work but third dosent. There isnt any need of testing p1 that is pump pressure if it has enough for 1 and 2 it has enough for third. You have speed clutches and directional clutches. If the directional clutches f or r was out it wouldnt move at all in any gear. The 3rd speed clutches are not getting pressure and locking up. Like stated above The linkage is the first thing to try. Can you feel it detent in 3rd.
well the bank rejected my offer, they would like 15k... for a busted tractor that may have tranny issues, needs a steerling clutch adjustment, pin and bush job on the blade, and a fuel issue resolved... I knew I hated banks...