Needing to do rear main replacement, but have questions.

[Afrojoe1449]

Hello All. As the title says I need to replace my rear main soon. It's been needing it but seems to be getting worse now and the potential for fire and the constant replacement of oil bothers me. I have a Haynes manual and have looked at some discussions here. I've already bought a transmission jack, a Motorcraft seal, and the special 100 dollar seating tool to replace the seal. However. I'm still worried about the process, what all fluid I'll need and how much, what parts I need to replace while doing it, and just everything I don't know that I don't know yet. It's a 4.0 OHV, 4x4, 5r55e. I know I'll need to drain and replace my oil. I know I need to discount the transmission (I'm hoping to leave the transfer case connected) I don't know if I need ATF and if so how much. I don't know if I need to replace any nuts or bolts or buy any specialty tools. I'm hoping I can do it in a day and a half. Maybe two and a half in my car port. I've never removed or done any transmission work other than pan drops and filter changes. So I'd love to hear from anyone who has done it that can teach me what I need that I might be missing. I'm worried about getting into this things and either making things worse or missing lots of work waiting for parts to ship in. Thanks guys! I'll try to reply to any messages ASAP

 

[rasouth]

My first advice is to take pictures of anything you might have to disconnect, such as wires, tubing, nuts, bolts, etc. That way you have a reference of where and how things go back.
I would first disconnect drive shaft, undo anything attached to transmission, support transmission, undo bolts to engine, might have to drop rear of transmission to get at upper bolts at top of engine, (a long extension or two is helpful), pull transmission and transfer case backward enough to get at seal, drain oil from engine if you want (not much oil will drip out after pulling seal) , pull seal out (a small screw driven into old seal might help with removal). I don't see a reason to change out fluid in transmission unless you just want to. Clean and lubricate new seal and area, press seal into place. I always used the old seal to tap new seal into place. It is the same size and doesn't matter if you damage it with the hammer. Reconnect transmission.
Sounds easier than it actually is. A lot of cursing and a few busted knuckles are probably in store. Follow manual for a more complete description and procedure. Basic tools are all that are needed. Some maybe metric size, most are standard.

 

[Afrojoe1449]

Thank you, rasouth. I've seen some suggest doing transmission pan drops and stuff before even discounting anything and I know you have to remove the transmission fill tube and cooler lines so I was unsure if lots of atf would come out in the process of that or not. I was hoping to avoid doing much with the transmission. I'm in need of a oil filter change anyways so figured I'd drain the oil and clean everything up in the process of replacing the seal to help identify any future or remaining oil leaks. Sounds like I might have all I need from your response luckily.

 

[Pete Deering]

Hello All. As the title says I need to replace my rear main soon. It's been needing it but seems to be getting worse now and the potential for fire and the constant replacement of oil bothers me. I have a Haynes manual and have looked at some discussions here. I've already bought a transmission jack, a Motorcraft seal, and the special 100 dollar seating tool to replace the seal. However. I'm still worried about the process, what all fluid I'll need and how much, what parts I need to replace while doing it, and just everything I don't know that I don't know yet. It's a 4.0 OHV, 4x4, 5r55e. I know I'll need to drain and replace my oil. I know I need to discount the transmission (I'm hoping to leave the transfer case connected) I don't know if I need ATF and if so how much. I don't know if I need to replace any nuts or bolts or buy any specialty tools. I'm hoping I can do it in a day and a half. Maybe two and a half in my car port. I've never removed or done any transmission work other than pan drops and filter changes. So I'd love to hear from anyone who has done it that can teach me what I need that I might be missing. I'm worried about getting into this things and either making things worse or missing lots of work waiting for parts to ship in. Thanks guys! I'll try to reply to any messages ASAP

There is a few videos on YouTube for our cars. Use a few long extensions together to get at the upper bolts. You can also access the bolts with the front splash shield removed. I also drain my tranny pan and fluid.

 

[Afrojoe1449]

Do you guys think I could drop and remove the oil pan while the transmission is out? I'm thinking about replacing the pan gasket while everything is apart. I'm seeing that most lift the engine to do this, but not many mention doing it with the transmission completely removed.

 

[rasouth]

I doubt you can drop oil pan without removing front diff. Mine is a '96 so it might be different than yours.

 

[Afrojoe1449]

Thanks again Rasouth. I'll probably just stick to tightening the bolts and calling it good to go.

 

[Afrojoe1449]

Well I got it all done a week or so ago. Immediately after reinstalling everything and filling it fluids back up I've got a worse oil leak than before. I'm worried that I messed up the seal install. But I'm going to try and check the valve covers and lower intake for leaks first. It might be the pan gasket I guess but it's a steady drip when running now.

 

[Pete Deering]

Sound like you did more thàn the rear main seal. What rear main seal did you uses? How long did it take you? Did you remove The transmission and transfer separately?

 

[Afrojoe1449]

I used the Motorcraft rear main seal with the included sleeve and used the OTC sleeve installer. I knicked the crank with a screw removing the seal but sanded the burr down and installed the sleeve and new seal using aenoribic sealer behind it as I had seen recommended here somewhere. I took the transmission off with the transfer case connected but due to the weight and size had to disconnect them after getting them on the ground and reinstalled them separately. I'd say it took me two days after work to take it all apart and about 2 and a half days putting it all back together. Only thing I did other than the rear main was replace the transfer case to extension housing gasket, drain and refill the transfer case fluid, and install longer breathers on the front diff, trans, and transfer. Only reason I mentioned checking valve covers and the intake is because I'd rather repair that than the rear main and if the rear isn't leaking now it would increase pressure elsewhere in the system I'd assume. Also I looked at it today and I'm almost certain I'm leaking at least some oil from the rear of the upper intake near that sensor that attaches to the block. I'm not sure if it'd be accountable for the amount I'm seeing though.

 

[Pete Deering]

What type of fluid did you use in the transfer case? And for the tranny? Where did buy the gasket that between the tranny and transfer case. Thanks for the information Pete