RBT-ZF Mystery part

[DaveM]

Just drained my RBT and this was stuck to magnet on drain plug. 4mm diameter and 10mm long. No metal filings in oil. RBT is 4 years old with 15,000 miles. Trans has been working fine, just occasional difficult engagement of 1st gear from complete stop. OK when rolling. Any ideas on what this is? Doesn't look like any roller bearings from ZF manual except possibly pinion bearing, part 403 or input shaft bearings 232 or 234? Locking bar part 659 or selector pad part 653?
Can't understand no metal filings and working OK. Thanks for any help.

 

[Mark Charlton]

Why not call Lloyd at RBT and ask him? He's easiest to reach in the morning, California time.

Mark

 

[Phil]

Dave:
Its been a while since I have been inside my ZF but that looks really close to a pin that would align the housings on the gearbox...but I would check it out...and while you are at it go buy a lottery ticket because you are very lucky that didn't get between two gears on the mainshaft or the Ring and Pinion.
Cheers
Phil

 

[Keith Stafford]

It does seem to have 'rotational' wear patterns around it? Suppose it's one good reason to stick a dirty great big magnet on the bottom of the case. K

 

[Ron McCall]

Can you place something beside the item so that we can get a idea of it's size?


Ron

 

[Erik Johnson]

It is a roller from one of your tapered bearings, at least I think it is. Difficult to tell for sure, but I would certainly get in there and check everything out before something more important fails. Just my .02

 

[Jac Mac]

Part #s 202/203,pins for thrust washers location, 503,pin for rev idler shaft location would be likely suspects or roller out of pinion roller bearing if its larger- doesn't look to be a tapered roller though.

 

[Cliff Beer]

That sure looks like a taper roller bearing to me. It has the characteristic rotational wear markings of a taper roller bearing at least. I don't know how only one might fall out of the cage, but it's conceivable the remaining rollers could be doing the heavy lifting without too much complaining going on.

 

[Jac Mac]

Sorry to labour a point, BUT taper roller brgs have tapered rollers-that one in post # 1 appears to be a parallel roller in which case it would come from the bearing adjacent to the pinion, or if its a locator pin. Rons suggestion of a ruler or object of known size in pic would help. Dave said 1st gear has become difficult to select which would suggest that it could be related to the thrust washer for that gear failing and introducing an excessive amount of end float.

 

[DaveM]

Jac Mac I'm not seeing some of the parts you list on my -2 diagram (your diagram is a -1 box?). Roller size is 4mm x 10mm. Sent part to Lloyd. Only possibility he can think of is part #206 double roller bearing on the input shaft. He can't see how roller would get loose though as bearing has a cage. This could also be as stupid as inadvertent introduction during an oil change. Was going to ignore it, but prudent thing is probably to send to Lloyd for inspection.
Concerning 1st gear stiffness I noticed access plug was tightened against 1st gear selector rail. Backing it off a little smoothed out gear engagement.

 

[Jac Mac]

I was thinking these rollers off pinion shaft in pic, but 4mm is ~0.160" dia x 10mm [0.400"] long which is more in line with the pins that locate those thrust washers and the reverse idler shaft in the -1 dwg. Be interesting to hear what Lloyd reckons.

On your -2 dwgs from RBT site, the rollers in brgs from low gear [#411] look the more likely culprit, could have been left behind if previously overhauled, pins #230 & 503 also likely.

 

[DaveM]

Dave:
Its been a while since I have been inside my ZF but that looks really close to a pin that would align the housings on the gearbox...but I would check it out...and while you are at it go buy a lottery ticket because you are very lucky that didn't get between two gears on the mainshaft or the Ring and Pinion.
Cheers
Phil

You are so right about luck Phil! Since Lloyd is out of the shop now I went ahead and opened the trans case. Notice one roller missing from part # 206 input shaft bearing. No damage to either R&P or gear clusters. Thanks to all of you for convincing me to not ignore this issue!

 

[Rich Roy]

Great that you found it! How did that "little Basturd" jump out of the cage? Photo shows some cage distortion. Did it get bumped by the out-put shaft when it was inserted?

 

[DaveM]

That's the remaining mystery Rich. Looks to me like something dented cage from camera angle (rear of trans). Trans has never been apart before. Will have to see what Lloyd thinks.

 

[Keith Stafford]

It does look like the cage was hit by the end of the shaft (during insertion) the domino effect knocked out the back roller, prior to the shaft being there to 'capture' it, so it has been in the bottom of the case since then,.... how did you do in last week's lottery? K