VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 29 transmission main drive bearing

I am rebuilding my transmission again after it began jumping out of gear on the mountain roads and chipped two 2nd. gear teeth. The resulting metal in the oil caused more damage. I replaced the gear and all bushings. I am getting a new counter shaft fabricated. I purchased a magnetic drain plug to capture metal chips. The main drive bearing also seems to have some rough spots. My question is why did TFS instruct me to remove the inner seal when installing the bearing? It seems that exposes the bearing to any particles in the transmission oil. Is there any problem with leaving the seal intact?

Because the original bearing did not have a seal.

I would consider keeping the seal and having it to the front,

the bearings that TFS sells are double seal bearings nomenclature 2RS typically. in the industry they are great noted as GREASED FOR LIFE. TFS has you remove the seal on one side (making it now a open bearing at least on the one side) and face the open side to the inside of the trans so that the bearing is lubed via the trans oil. this also tends to keep the bearing cooler since it is constantly getting fresh oil from a large reservoir (transmission). Keeping the seal on the outside helps limit the amount of oil going to the outside and reduce possibilities for leakage. you could leave the seal on both sides however when the grease dries up and serves it term (could be short term or long term depending on the grease they used) you will have to remove the bearing and replace it, probably not in our lifetime unless you drive a lot and heat up the trans bearings. Also sealed bearings tend to run hotter as they can not cool themselves other then heat transfer through their balls & races.

you are correct that open one face allows for contaminants to enter bearing and destroy it !! however if you have clean fluid and proper environment and change fluid then you should be ok, but failures do happen and in those cases ALL bearings, seals, and bushings should be replaced. trans should be completely disassembled and everything taken apart and cleaned thoroughly. one grain of sand will destroy a bearing and wear a bushing out.

They are Axis brand, better than many but NOT the best on the market. We have only use SKF in our products since inception (industrial pump manufacturer), and sometimes use Timken if the customer specifically requests them and we can not talk them out of it (we tell them that doing so VOIDS our warranty). we buy millions of them each year and very small failure rate in the field and 99% of those are end user induced!!

figure the RPM rarely gets around 2000, since peak rpm is around 2400 in these vehicles.

Thanks for the feedback. I guess I'll try leaving both seals on this time and hopefully I won't need to do this again. I probably should have ordered SKF.

I agree with BearsFan315 and would strongly consider removing the rear seal.

If you are having trouble with the transmission jumping out of gear take a good look at the fore-aft movement of the main gear cluster in relation to the input shaft. Another VCCA member showed me the trick to install a shim to move the input shaft slightly to the rear and limit that movement.

either way with the metal in the oil you would have to replace the bearings !!
Axial bearing is $19.50
SKF bearing is $75.50

I do need to check the alignment of the gears. In a previous post Chipper mentioned that the teeth can wear at a slight angle and cause it to jump out of gear. That may have been the cause.