Bearing help

[1phrogguy]

Hi All,

I've got a new tailshaft on a rebuilt H42 and the Transfer case bearing doesn't quite fit. It's .01 under.

What is recommended here? Heat?
TIA

 

[shawnfj40]

What do you mean it’s under?

 

[spotcruiser]

It might just be the way it's photographed, but that bearing looks too wide. Are you sure that's the bearing for the transmission output/transfer input? Are you sure that's not the transfer front output bearing or something like that?

 

[1phrogguy]

@spotcruiser It's a pretty close up picture, and at a weird angle I guess, but that is the correct bearing. It slipped right on and off when I swapped it out 6 months ago for the one you see pictured.

@shawnfj40 Inner Diameter of the bearing is .01 inches less than the diameter of the shaft. IIRC measurement for shaft was 12.7 and the bearing ID was 12.6

@65swb45 any suggestions?

 

[shawnfj40]

I understand your issue now. You need to find out which one is wrong. The shaft or the bearing. You said it was a new shaft? It may well be manufactured out of spec. I would get ahold of them or machine .01 off it if the splines will still engage (have you checked them)?

 

[shawnfj40]

Heat is definitely not the answer though.

 

[1phrogguy]

I can't really machine it as is. I just bought this trans rebuilt and it's all put back together, minus this last bit of the TC before install.

Seeing as very little material needs to come off each tooth down the shaft, would sanding it down work?

 

[B y r o n]

Are you sure that you only have .001" clearance issue and is it the total length of the splines or only near the end where the bearing sticks. If it's no worse than the .001" I'm thinking that is a very light press fit and you should be able get the bearing down the splines and into place for final assembly. You might want to double check this though.

 

[1phrogguy]

Total length down the splines, I'll have to check on that, good tip. .01 is the difference though.

 

[65swb45]

I run across this issue regularly Jon, and have for the 30 years I’ve been doing this. Often they are just as tight during disassembly, which is why there are multiple threads on here about SSTs and homemade tools to pull off a t-case that SHOULD just slide off. And remember, that is with all OE parts.

I have a well-used 12” section of 1.5” galvanized pipe for my SST to provide driving force directly to the inner race of the bearing only. An old outer race is welded to the other end so that when the bearing reaches the case I can tap on the OD if need be.

Form follows function.

 

[1phrogguy]

Shaft is the same OD all the way down.

@65swb45 are you suggesting I press the bearing on to get it started, then drive it home? What happens when I need to replace it?

If this thing should slide, I'd like to make it happen now. I'm thinking about shaving just enough off the teeth at the end of the tailshaft to match the correct size for the bearing to slide up to the case. I don't mind having to use a SST to get it fully home.

 

[shawnfj40]

Now that I think about it, I've almost never had one just slide off. If you had the old bearing you could measure ID on it for comparison. You might get someone to measure a new TOYO bearing to compare. It may just be a out of spec bearing and if you machine that shaft to match, theres no going back. Without a new shaft at least.

 

[73FJ40]

@shawnfj40 Inner Diameter of the bearing is .01 inches less than the diameter of the shaft. IIRC measurement for shaft was 12.7 and the bearing ID was 12.6

 

[73FJ40]

[/QUOTE

Please clarify the dimensions. Is the interference really 0.0100 Inch, which is more than 3/32"? What do your numbers (above) 12.6 and 12.7 refer to?

 

[Spike Strip]

You could try leaving the bearing in the sun until it's too hot to touch (easy in S. Calif ) and at the same time putting some ice on your shaft...

 

[Dynosoar]

I have used a hot plate (Yes, a kitchen style hot plate) to heat up the bearing (Pick it up with a welding glove on please) than you just drive it home with a little persuasion.

There is a big difference between .01 and .10, you mentioned above 12.7 and 12.6, thats a delta of .10 not .01

 

[1phrogguy]

Thanks all,

I see the confusion @73FJ40 , hell I probably wrote the wrong thing down. What I do know is that the bearing ID is .01 inches smaller than the OD of the shaft.

General consensus from this post is to ream that bitch on and go.

What's the harm in taking some material off the teeth at the last two inches or so of the tailshaft? Why fight this thing on and off, continually, for the remainder of it's service life?

 

[73FJ40]

@1phrogguy

I'm not a bearing engineer, but if you really have 100 mils of interference fit, I can't imagine you could hammer that on to where it belongs.

If you could, I'd be surprised if the bearing still worked. My humble opinion, others may know better...

 

[peesalot]

I agree that 100/1,000 aint gonna hammer on, to much interference. If you do manage to smack it on , removal will be interesting IMO.
?, does the input gear, PTO gear , and spacer fit over shaft ? If you do plan to remove material you will have to pull case off as I do not think you can work the splines where the bearing sits while the T-case is mounted. That being said I would not be scared to remove the T-case & sand the shaft down & if you have the tools maybe sand on the ID of bearing race as well until you achieve the slip fit.

 

[1phrogguy]

@peesalot I concur, going to pull the TC so I can reach where the bearing rides. -Smooth down the shaft, re-attach TC and slide bearing into place. It'll be in work next week.

@73FJ40 I was thinking the same, I don't want to mess with the bearing if at all possible.

Varied opinions thus far, If there's a reason not to take material off the shaft (just up to where the bearing rides) I'd like to hear it.

Jon