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Dana 20 intermediate shaft tightness

SDBMtber

Jr. Member
Joined
May 20, 2018
Messages
130
Just wrapping up a Dana 20 rebuild (I hope!). How tight should the intermediate shaft be? I installed all new needle bearings, spacers and thrust washers on a new shaft as part of the super deluxe kit from WH. As I was sliding the idler gear down into place, I noticed it didn’t just drop right in between the thrust washers. Definitely more snug than when I removed it. Could slide it in by hand, got the shaft run through and pressed in to the opposite side.

There is still significant drag on the internet’s shaft. Is this normal? When I engage the front output, I can turn the yoke by hand, but it takes some effort. Do the thrust washers normally wear in a bit or is something bad going on? Not sure what it could be - other than keeping everything in place with lots of grease during assembly, this seems like the simplest part of the transfer case.

Thanks!
 

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SDBMtber

Jr. Member
Joined
May 20, 2018
Messages
130
Crisis averted. I tightened down the bolt on the shaft retainer and it eased up. I guess I must not have had the shaft positioned 100% right. It’s there now.

In case anyone else gets antsy like me to try it out before finishing the whole install...
 

JB Fab

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Mar 21, 2004
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1,240
Yeah, usually a couple of smacks on the side of the case with a brass hammer takes care of it. in some kits I have seen the washers be too thick as well.
Remember, don't use differential gear-lube, the pressure additives attack the brass.
 

Justafordguy

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Sep 26, 2009
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Remember, don't use differential gear-lube, the pressure additives attack the brass.

Interesting, I have run Lucus synthetic 90w for years without any issues. I wonder if the synthetic is safe for the brass?
 

73azbronco

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Yeah, usually a couple of smacks on the side of the case with a brass hammer takes care of it. in some kits I have seen the washers be too thick as well.
Remember, don't use differential gear-lube, the pressure additives attack the brass.

Boom, same ^^^^, that case flexes.
 

sykanr0ng

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Aug 11, 2014
Messages
5,363
Even the MT-1 rated gear lube has the molybdenum disulphide and other sulphur compounds that attack copper alloys.
I would not trust any GL-5 rated gear lube in a Dana 20, use a GL-4 gear lube.

Or do like Ford said and use a 50 wt oil.
 

Justafordguy

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Sep 26, 2009
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Thanks for the info, I'll try something different next time I change it.
 

JWMcCrary

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Oct 14, 2004
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5,001
Yeah, usually a couple of smacks on the side of the case with a brass hammer takes care of it. in some kits I have seen the washers be too thick as well.
Remember, don't use differential gear-lube, the pressure additives attack the brass.

When I put in tera lows I could not get the new washers in, checked the new ones against the old ones and was obvious difference in thickness. I reused the old washers.
 

Justafordguy

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If one is gear oil and the other is engine oil they are the same functionally but measured differently.

I just checked,
On the Lucas web site it looks like one is "gear oil" and one is "Transmission oil".

They both meet API MT-1 and the 50W Transmission oil has a note that says it also meets the gear oil standard of SAE 75W-90 under J306 (which is what the gear oil is). Odd that they sell it as two different products.
 

JB Fab

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Mar 21, 2004
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My choice for tha Dana 20 is Mobil Delvac 1 Transmission Fluid 50

Made for splash lubricated manual transmissions, has an excellent temperature range and extremely long life.

That would be another great choice. Most of the D20s that I have tor down that have had regular gearlube in them have black scoring on the face of the thrust washer and sometimes scoring on the end of the idler gear. I even have seen the thrust washer fail where the the bronze face separates or the washer spins an ruins the case.
The D20 is a great case.
The thing is, almost every one reading this that has a D20, is pushing it over it's original design limits so care is needed.

I have seen where some folks would machine the idler gear to accept bearings on each end (like an NP205).... old 1970's racing trick
 
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