9" Detroit - Pinion Seems Too Loose

[Past_Miner]

I crawled under my rig the other day and checked the pinion on my 9" a couple of days ago because it seemed like it was way too loose. I pulled the driveline and the pinion would rotate at least 1/8 turn with the tires on the ground. I fugured I had a major pinion problem so I pulled the third member to check backlash. It turns out the gear backlash is correct. The pinion travel seems to be from inside my detriot locker.

Is this normal? It doesn't seem like it should be that loose in there.

 

[Mherriford]

I have heard that detroit lockers have that much play in them, or I could be totally wrong in which case I am sure that someone will jump in and correct me

 

[Yellow_66]

I just installed my new Hi9 third member/full width set up and the pinion moves about the same amount as your seeing.

 

[JWMcCrary]

I hope it's normal..mine is the same way.

When I first started driving mine I thought several times that something had to have broke in the rear. When you back out of a space in a parking lot making a sharp turn and gave it much throttle before it straitghened out, it would bang so loud you would think something should be laying in the parking lot.

 

[okorangebrnco]

I don't think you have a problem at all. Mine moves about an 1/8th maybe just a hair more. Out of all the 9inches I have built after the break-in period with the detroits they all develope a little pinion play as such. One thing we would do is build them alittle on the tighter side so it would not be as noticable.

 

[BlackHorse]

That's how mine have all been and I've had more than a few in different rigs. People have had me take out brand new units just to check that somthing was not broke. I tell them it's just the Detroit, I told you it would do that before we installed it. Most have been happy with it but I've taken out a couple and replaced them with LS units for those who just didn't like em.

 

[Past_Miner]

Ok I feel better about the drtroit. I won't worry about it. I just checked the pinion support bearings though. The front one is shot and I can't get the pinion pressed out of the bearings. It's like the thrust washer between the outboard bearing and the yoke is welded to the pinion shaft. I suppose I had too much preload.

Any suggestions for that one? I don't want to break the pinion support.

 

[mudonthetires10]

I have a Detroit and mine has play in it as well. I'm pretty sure its a common thing.

Buy a Daytona pinion support. You can find them under $100, but usually they are about $100-125 retail. You will have to change to bigger bearings, but it's worth it.

 

[jabranovich]

9"Detroit

That much play is normal a Detroit is worm gear driven and until all slop is out of each worm set it feel slopy,plus you add backlash and spline slop on axles it all adds up.Sounds like pinion bearing got hot enough to gall itself to pinion,as a last resort,try pulling pin.supp. out of pig and take a torch and carefully cut roller cage and inner race,then try press,pinion pre load drag on new brgs.is 15-20 inch.pounds of drag w/out ring gear in.

 

[00gyrhed]

Its the way they work. Anoying isn't it?

 

[76Broncofromhell]

That much play is normal a Detroit is worm gear driven and until all slop is out of each worm set it feel slopy,plus you add backlash and spline slop on axles it all adds up.

Detroit lockers aren't worm gear driven. They are a dog and tooth design with a ramp to allow the clutch teeth to overtake the drive (carrier) teeth when a given side exceeds the speed of the carrier.

The slop comes when you change the loading on the teeth as there is an opening to allow the driven clutch to move so it can unlock.