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76 D4D new toy with problems

Un4gvn

Active Member
Joined
Nov 30, 2022
Messages
41
Location
Pine Bluff AR
Anyone with input on the strength of the power shift trans? I've been looking at some of the different 3304 engines with turbo. I'd really like a turbo don't really need I don't think but it would sound good! I know nothing about the powershift trans and what it is capable of.
 

Puffie40

Well-Known Member
Joined
Apr 5, 2010
Messages
208
Location
Southeastern B.C.
Copperheadmarine on youtube did a 3304 turbo conversion on a direct drive D4D, I think his videos will have a few tuning tips that might be helpful.
 

OzDozer

Senior Member
Joined
Jan 18, 2007
Messages
2,207
Location
Perth, Western Australia.
Occupation
Semi-Retired ..
The powershift is merely a multiple set of planetary gears with multi-plate clutches mounted around the outer circumference of the gear sets. Oil under about 300 psi pressure is directed into the appropriate clutch packs by the spool valve (which is operated by the transmission gear selection lever), which clamps the plates together and thereby selects that particular speed or directional planetary gear set.
The Cat powershifts are pretty robust, and planetary gearsets spread the load, unlike simple spur gears in single-countershaft, direct drive transmissions.
The primary weakness is likely to be in the transmission pinion, and the bevel/ring gear on the cross-shaft. The bevel/ring gear is unsupported adjacent to the pinion, unlike some bevel/ring gears in truck differentials - so the potential is there for the pinion and bevel/ring gear to spread apart under extreme load, and shift the tooth contact pattern, to the point where teeth may fracture.
The steering clutches are more likely to give trouble with a sizeable power/torque increase, and the final drive is only a single reduction - a straight-cut pinion on a straight-cut bull gear - which is weaker than the double reduction final drives of the bigger Cats.
 

Puffie40

Well-Known Member
Joined
Apr 5, 2010
Messages
208
Location
Southeastern B.C.
I should ask: does your powershift have a lever to disconnect the tracks for using a winch? Our 83J has such a transmission. The pinion has a needle bearing that allows a dog clutch to disconnect the tracks, and that is how the pinion and ring gear failed on our D4D - the needle bearing failed, and the reduced contact pattern wrecked the pinion and ring gear.

Look for a short lever on the floor near the base of the shifter tower - that's the clutch for the pinion.
 

Un4gvn

Active Member
Joined
Nov 30, 2022
Messages
41
Location
Pine Bluff AR
I don't think this one does but I'm going to buy another tomorrow that came with the winch on it so it may have what you describe. I think this dozer might give up parts to put the other together. The new one has a lot less use on it. It is setup as a pipelayer so it has probably had an easier life than mine.
 

TomA

Well-Known Member
Joined
Aug 17, 2012
Messages
143
Location
Mariposa, CA
Most Cat diesel engines can be set up for much higher horsepower without a turbo. Mother Cat only gives you the amount the machine can handle and endure. Yes the finals are likely the determining factor.
 

Un4gvn

Active Member
Joined
Nov 30, 2022
Messages
41
Location
Pine Bluff AR
The dozer I'm getting does have the lever for the winch. It is in better condition than mine with a lot less hours on it. But it's been sitting so long so stuff is not operating as it should. Neither of the steer levers will move not sure what it will take to get that stuff free.
 

OzDozer

Senior Member
Joined
Jan 18, 2007
Messages
2,207
Location
Perth, Western Australia.
Occupation
Semi-Retired ..
If just the levers themselves are binding at their pivot points, that's no biggie. But dry steering clutches that get water in them are a PIA to clean up and get working again. Nothing else to do there, but some major dismantling.
 

Un4gvn

Active Member
Joined
Nov 30, 2022
Messages
41
Location
Pine Bluff AR
I believe it is just the shaft where it enters the housing. I don't think it will require major surgery. I hope...
 

D6 Merv

Senior Member
Joined
May 10, 2007
Messages
653
Location
Coromandel Peninsula. New Zealand
Occupation
Self employed bulldozing contractor with a D6D D4E
powershift D4D transmissions are fairly bulletproof. Only weakness is the seals on the rotating clutch for 1st gear. Bevel gears and pinion will only fail if a bearing fails first. The dry steering clutchs are a pain. Most of the later D4D that came down under to new zealand were japanese build which came with factory wet steering clutchs and brakes. The few 83J ones from USA were changed to wet by dealer here. Weakest part on D4D is single reduction final drive gears. Though the later 7K gears are fairly good. Beefiest f/d gear upgrade came in on the D4E. They have big coarser pitch gears.
 

Mcrafty1

Senior Member
Joined
Oct 12, 2019
Messages
441
Location
Central Maine
Occupation
Earth work
Is there a way to delete threads on here?? I don't want any of my stuff on this forum.
Maybe if you throw a hissey fit, mean mouth the other posters and the like the mods may wipe it, otherwise afaik there is a very tight window of opportunity to edit/remove posts after posting, if you miss that you pretty much have to live with what you post.
 
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