Transmission shaft oil seal (front)

Jim Paterson · Mar 1, 2013

I have an oil leak from the trans at the point where the belly pump is driven from (transmission countershaft oil seal). How difficult is this to change? Do I have to open the transmission? Do I have to drain the gear oil?

Thanks for your advice.

David G · Mar 1, 2013

Yes, you have to drain oil, spin the coupler off and replace the seal, fairly easy.

Bob M · Mar 1, 2013

Easy seal to change:

1 - Drain a couple gallons from the transmission to lower the oil level. Or drive the front end onto some blocks so the front's 18" or so higher than the rear.

2 - Remove (unscrew) the drive coupler. Stick the transmission in low, or engage the PTO then hold the PTO shaft from turning with a pipe wrench. Now grab the coupler with a big pipe wrench and give it a heave (it's normal right hand threads). Once started the coupler will spin off easily.

3 - Remove the capscrews holding the seal retainer then pry it off.

4 - It's now a simple matter to remove the old seal and press in a new one.

Note the new seal will be about 1/2 the thickness of the original you take out. This is NOT a problem. Simply press it in flush or a bit further and it's good to go.

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Reverse the process to put it back together. No need to wrench tighten the coupler - spin it on finger tight and it will tighten itself the first time the pump is loaded.

Tip: Consider replacing the upper seal while you are in there! Can almost guarantee if the bottom seal is worn out then so is the top one.

Wayne in MN · Mar 1, 2013

Clean the area with a wire brush, etc. to locate 3 capscrews.
Lock the brakes, put the transmission in reverese, and remove the pump drive coupler(leftty-loosey). A long square bar or pry bar helps.
When the cast seal housing is removed, gear lube will seep through the bearing.
Clean all gasket material from the transmission and seal housing, press the new seal in (garter spring to the oil side), install with a new gasket and tighten the capscrews snugly. Install the drive coupler by hand ( it tightens when being used) or tighten with a bar if there is no belly pump being driven.

mike1972chev · Mar 1, 2013

While I was in there,I would do the upper seal on the input as well.

Ol' Gimpy · Mar 1, 2013

Always check the flanges for wear grooves,may have to use a "Speedi-Sleeve" to correct wear and prevent leaks.

Transmission shaft oil seal (front)

Jim Paterson

Member

David G

Well-known Member

Bob M

Well-known Member

Wayne in MN

Well-known Member

mike1972chev

Well-known Member

Ol' Gimpy

Member

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