: Rear main seal install tool confusion

01-19-12, 01:42 AM
So, I looked in FSM for 98 Deville, it says I need J38817 tool. So I go on ebay, find one, and pay for it. AFTER I pay for it I read the item description which says :

4.6L, 4.0L (1993 to 1996.5) To install the rear seal on the Northstar engine, first position the seal on J 38817 then attach the tool to the crankshaft. Turn the large wing nut until the seal is bottomed and in a square position. NOTICE: A seal change was made in 1996.5 that requires a different installation tool, J42842-A. This tool is designed to install the floating seal that is pressed to both the block and to the crankshaft. J38817-A should not be used on this style seal. The new seal does not back service 1993 to 1996.5 engines!

So what gives? which tool is correct for my '98. What the FSM says or this guys description. ??

01-19-12, 07:22 AM
I think you will need the updated tool. The updated rear main seal design requires a lot of force to press it onto the crankshaft correctly. I have tool J-45930A which is the replacement tool to J-42842. Tool J-42841 is also handy in removing the old rear seal, just don't drive the screws in too deep.

01-19-12, 05:08 PM
Here's the TSB:

Bulletin No.: 00-06-01-005A
Date: August 29, 2006
Cartridge Type Crankshaft Rear Main SealModels:
1996-1999 Cadillac Concours, DeVille, Eldorado, Seville
1996-1999 Oldsmobile Aurorawith 4.0L or 4.6L Engine (VINs C, Y, 9 - RPOs L47, LD8, L37)
This bulletin is being revised to add additional information on the Cartridge Type Crankshaft Rear Main Seal. Please discard Corporate Bulletin Number 00-06-01-005 (Section 06 - Engine/Propulsion System).


A cartridge type crankshaft rear main seal (Figure 1 - number 3) has been released for the 4.0L and 4.6L engines identified above. The cartridge type crankshaft rear main seal is identified by a metal flange located on the inner diameter of the seal which presses onto the crankshaft (http://www.alldatadiy.com/alldata/AFI~V29886898~C26308~R0~OD~N/0/41746678/42420861/42420864/42420865/34853741/100411974/34853743/34872030). The previous crankshaft rear main seal (Figure 1 - number 2) is a conventional lip type seal and has a soft rubber like material in the center where it contacts the crankshaft instead of this metal flange.

The cartridge type crankshaft rear main seal is retained to the crankshaft (http://www.alldatadiy.com/alldata/AFI~V29886898~C26308~R0~OD~N/0/41746678/42420861/42420864/42420865/34853741/100411974/34853743/34872030) with a press fit that requires over 45 kg (100 lb) of force to remove or install. These high removal and installation forces make it necessary to remove the cartridge type crankshaft rear main seal with Kent-Moore Tool J 42841 (Figure 2) and install it with Kent-Moore Tool J 42842 (Figure 3). Refer to SI for Crankshaft Rear Oil Seal Replacement (Cartridge Type Seal) for instructions on the proper use of these tools. In addition, the cartridge type crankshaft rear main seal incorporates precise internal sealing surface relationships which are maintained for optimal sealing by using Kent-Moore installation tool J 42842.
DO NOT use Kent-Moore Tool J 38817-A (Figure 1 - number 1) to install the cartridge type crankshaft rear main seal. Attempting to install the cartridge type crankshaft rear main seal with Kent-Moore Tool J 38817-A will result in a damaged or improperly installed crankshaft rear main seal and will damage Kent-Moore Tool J 38817-A.
The cartridge type crankshaft rear main seal will be used to service 1996-1999 past model engines built after Engine Unit Number (EUN) T10L423109 which were installed in vehicles built after March, 1996.


01-19-12, 07:54 PM
Thanks folks so much, that clears things up considerably !!!

01-19-12, 08:02 PM
I have the newest variation of the tool - bought direct from SPX - very beefy - used once - no expected future use - in case someone wants to buy it for a good price.

Oh - the tool I have is the installer:

Ref B JLL Sales Order 219853
PO RICHARD Order Date 01-14-2008
Item Quantity Price Discount Amount
J-45930-A 1 262.94 262.94
INSTALLER, REAR CRANK SEAL Estimated Ship Date 01-16-2008
4554 1 13.36 13.36
GAUGE, TORQUE ANGLE Estimated Ship Date 01-16-2008

Tax Authority Rate Amount
State 5.600 15.47
Local 2.600 7.19
Total Amount

johnny kannapo
01-21-12, 04:39 AM
Good golly $298.96!

This is on page 6 about 1/3 of the way down the page of this amazing
thread that is worthy of reading every page & clicking every link.


01-24-12, 09:22 PM
I guess that might work, but I would be nervous - if the seal is damaged or improperly installed, the whole cradle has to come out again and then the engine (or trans), has to come off the cradle. The rear main seal installer was actually only $262.94 - I also bought something else on that order.

johnny kannapo
01-25-12, 03:41 AM
It's not rocket science, It just needs to be pressed in evenly-squarely.

01-25-12, 09:58 AM
I just got a J-45930 Kent-Moore from ebay for $49.99, missing nut and bearing, but I have the bearing and the nut.

01-25-12, 09:39 PM
That seems fair enough. I looked and looked and looked back in the day - never could find one used or for a good price.

(BTW, I would have sold you mine for that, complete, and with the 2 sets of different size bolts)

01-25-12, 10:30 PM
I wish I had known as I sure would have taken you up on that price.

01-26-12, 07:20 PM
Sure - I would have been thrilled to have paid only $50, too! I still don't regret paying what I did - it was worth it for the peace of mind that I had used the proper tool and wouldn't have any problems.

03-14-12, 08:34 PM

If you still have the tool, give me a pm.


03-21-12, 05:50 PM
It's sold, but here is what it looks like - very beefy - weighs about 4 pounds - there are 2 sets of bolts for the crankshaft output flange - I believe 2005 and earlier are one size - 2006 and later the other size:

03-24-12, 02:58 AM
Steve - received your money order - all boxed up and shipping out tomorrow (Saturday)