Sounds like a TON of work- congratulations on a job well done.

Just wanted to share that I finished the pinion seal job today. I ended up pulling mast and differential/tranny as an assembly. Split the diff and tranny. Then disassemble tranny. Removed and replaced pinion seal. Also replaced pinion bearings and races. Pulled forward and reverse clutch packs and replaced piston seals. Reassembled everything using permatex as suggested. I did this job on site at customer location. My hats off to you for getting this done in 16 hours. I was really cranking and it took me 20. Anyhow, thanks again for the input.

I appreciate everyone's input. You guys answered my question regardless of which way I decide to do the job. I basically needed to know if the tranny had to be disassembled and about how much labor would be involved. Huge thanks to everyone.

This debate clearly shows that there's more than 1 way to do a job, whichever way you feel more comfortable doing is the key to success.

ive been working in this business for 30yrs 25 for hyster co it is true you can pull the engine but truthfully it is more work.

got to disagree on this one worked on hysters for 19 years so i know what im doing never pulled a mast or axle to do the tranny far easier to pull the engine agree its about a 16 hour job and definitely use permatecs 11 on the edge of the seals. On the sealing face of the diff and tranny use a thin smear of gasket sealer and make sure the joining bolts are tightened to the correct touque cant remember what it is now.

dear lts1 regarding your pinion seal problem although it may seem easier to pull engine it is faster and easier to pull mast and then pull trans and diff as a unit then separate on floor done many of these it is easier to repair when it is completely out of forklift it is about a 16 hour job and will save you a lot headaches plus you have to make sure you seal goes in straight and your diff and trans cases are clean or they will leak and one more thing put permatecs11 on edge of oil seals

Lifter, you are a life saver. Thank you for the advice. You saved me a lot of time. I would have pulled the mast, then differential, then the tranny. I will quote in the clutch pack piston seals to the customer. Man I appreciate your help!

You need to remove the engine and then the the transmission from the axle and do a complete transmission strip down and remove the transmission output shaft to get at the seal check for any shims behind the bearing and if there are any make sure you replace them. Its a big but fairly easy job. While the transmission is down i would replace the clutch pack piston seals these do go hard with age and can fail. Hope this helps

BBforks, thanks for replying. I read the posts about the komatsu seal failure and the field repair that was applied. My guess is that tranny pressure will continue to push tranny fluid into the differential. This being the case, tranny fluid will eventually spill out of the diff vent. So like the komatsu I would have to run some kind of relief hose back to the tranny. I don't know if I can bring myself to do something like that. My customer doesn't mind paying for labor and I don't really mind doing the job. I just have to try and figure out how much of the tranny I have to take apart to get to that seal. I actually have a breakdown of the drive train and I still cant figure out what has to come apart. Break down does not show pinion side of the tranny. Just a breakdown of assemblies. Pinion shaft has a nut on it so I am guessing I can only get to that nut from inside the tranny.

I'm not sure with the specifics of your model, but Komatsu's did the exact same thing- the seal went bad between the trans & the diff. There was no bearing damage, just a seal failure. In fact- the customer ( a large national trucking company with hundreds of these lifts)- just let the old seal be & ran ATF in the diff with no problems.