Make payments with PayPal - it's fast, free and secure! registry | CVN on Facebook | tech | news | email login Make payments with PayPal - it's fast, free and secure!

Welcome to CVN - Your Panther platform headquarters!

Custom Search

Topic Options
#4071518 - 07/22/20 06:08 PM Should I replace ext. bushing or just trans seal
Brett04 Offline

Registered: 09/17/13
Posts: 23
Loc: Southern PA
My seal at the rear-end of the transmission is leaking. I was going to replace just the seal, then I saw that it is a good idea to replace the extension-housing bushing at the same time (the bushing for the slip-yoke).

I'm finding limited options for places to get a bushing, and they all say it is for the 4R70W transmission. Mine is a 4W7P-7000-EA (if I'm reading the tag correctly). But I have a vague recollection that the 4R70W used the same extension (my extension is RF-F3UP-7A040-AA).

Does it make sense to replace the bushing when replacing the seal?
If so, will the extension-housing bushing for the 4R70W fit my transmission?
2004 CVPI

#4071530 - 07/22/20 07:34 PM Re: Should I replace ext. bushing or just trans seal [Re: Brett04]
Lance01 Offline

Registered: 04/02/18
Posts: 333
Loc: Pa
I'm not the transmission expert but I would just change the seal and leave the bushing alone.

I have heard tailshaft bushing is a little tricky to install correctly and one transmission builder said once the new bushing is installed you can have problems where the yoke don't want to fit into the tailshaft.

Btw, there is a special tool to install the tailshaft seal correctly but I got away with just taping it flush with a hammer and haven't had any issues.

#4071540 - 07/22/20 08:02 PM Re: Should I replace ext. bushing or just trans seal [Re: Brett04]
RF_Overlord Offline


Registered: 12/14/02
Posts: 7121
Loc: MA
Brett, your car has a 4R70W (or 4R75W)...they both use the same bushing and seal.

In case you weren't aware, replacing the bushing involves removing the tailshaft housing which means removing the crossmember, a job best done on a lift, not in your driveway.
'03 Mercury Marauder (The Blackbird)
Trilogy Motorsports supercharged #61
Too many mods to list / Driveway Queen

'04 Grand Marquis LS Limited Edition (Spruce Green)
Daily Driver (Thanks, Adam!)

'00 Grand Marquis GS (Silver)
Rotted frame and broken transmission crossmember
Being resurrected...slowly.

#4071596 - 07/22/20 11:41 PM Re: Should I replace ext. bushing or just trans seal [Re: Brett04]
88grandmarq Offline

4R70W rebuilder

Registered: 07/10/02
Posts: 6816
Loc: Indiana
where are you seeing the leak? on the slip yoke? or further back around the U-joint?

there are 2 different seals on the police transmission the long output shaft.
2011 P7B - retired Jay county Indiana Sheriffs car
2003 Lincoln Town Car Signature - 3.27 RAR, dual exhaust and J-mod - SOLD 09/2011
89 Crown Victoria LX- HPP Box - SOLD 09/2010
88 Grand Marquis LS - The original - Totaled 5/2006

I rebuild AODE/4R70W/4R75E Transmissions, check out my Facebook page for my latest project;

#4071634 - 07/23/20 10:55 AM Re: Should I replace ext. bushing or just trans seal [Re: Brett04]
BigMerc96 Offline

I know nothing
Posting Addict

Registered: 06/05/10
Posts: 19770
Loc: I can see Detroit from here!
If you opt to replace the bushing, I'd recommend buying a whole new (or remanufactured) extension housing. My '98 had a bad bushing, looking into replacing it, I discovered that without special tools you really do need to take the housing off the car. So I decided to buy a remanufactured housing, and I'm glad I did, because after fighting with it to get the housing out of the car (transmission crossmember put up a HUGE fight), I really was not in a mood to then have to drive out the bushing and seal and then hope I got the new one driven in straight. It was 100% worth the extra $50 over just buying the parts to just be able to bolt in a new housing and be done. 4R70W/4R75W/4R75E extension housings are readily available both new and reman online, I bought a reman one from a company out of Ohio on eBay, it arrived with the bushing properly installed, with the new seal, and the gasket that goes between it and the transmission for something like $70.

On the "long" housings like a P71 and Town Car use, there is also an o-ring on the output shaft that can wear. This is what 88GrandMarq is alluding too. He would know better than me but I believe that o-ring requires removing the housing to replace, and when it does leak the fluid will usually seep out thru the weep hole in the u-joint yoke rather than around the output seal like when the bushing or extension housing seal leaks.

2006 Audi A6 ~132k miles, stock.
1998 Mercury Grand Marquis LS HPP ~100k miles, slowly acquiring modifications.
1997 Town Car Cartier ~145k miles, Ported Plenum, Gutted Airbox, Contour E-fan Retrofit, Dual exhaust with Magnaflows, cats deleted, MSD Ignition, KYB Gas-A-Justs, P71 front bar, air ride reinstated, Projector retrofit, Caddy 4-note horn retrofit, Wood rim steering wheel retrofit, holistic weight reduction as the parts fall off..
1996 Mercury Grand Marquis GS 117,485mi. R.I.P. 7/14/12 frown

#4071860 - 07/25/20 11:02 AM Re: Should I replace ext. bushing or just trans seal [Re: Brett04]
Brett04 Offline

Registered: 09/17/13
Posts: 23
Loc: Southern PA
I appreciate all of the advice. I put the new seal in (using a piece from a ball-joint kit to drive it in place). I did not change the bushing, but checked for any play in the bushing after re-installing the driveshaft. I did not detect any play.
2004 CVPI


Who's Online
5 registered (chrmaka, Jasper425, PCdude95, 99SigTownie, tybalt92), 89 Guests and 108 Spiders online.
Key: Admin, Global Mod, Mod
Email Login
EMail Login Name
 New users, sign up!
Top Posters (30 Days)
bluejay_32 185
BigMerc96 75
ClayBelt 69
Ponyguy 63
Old_Guy_Stu 63
a_d_a_m 62
TheCableGuy 55
Moby_Vic 52
RF_Overlord 37
Psxmoe 36
Member Spotlight
Member Since: 08/28/09
Posts: 14557

Copyright 2000-2015 by and Steve Spaulding. All Rights Reserved.
The photographs, graphics and data contained in this Web site are the properties of the contributors, or and may not be used without expressed written consent. is not affiliated with the Ford motor company.

Happily consuming the fuel saved by Prius owners!