I have searched high and low for a "how to" for gearbox removal and main seal replacement. I did see the nice main seal thread by one of our more knowledgeable members here and that was very helpful. However, i swear that I have seen a thread (or someone's project) describing how to remove the transmission, flywheel, and clutch to get at the main seal area. Can anyone point me in that direction please? Thanks.
Transmission Removal For Main Seal Replacement How To
- Thread starter t6dpilot
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The info how to do it is definitely on this forum.
Search Clutch repairs or transmission removal to find a thread where someone was talking about dropping the transmission. I’ve read many threads about their experience.
Then search rear main seal. @Poser has a very good write up in the 40’s section. I used his method and it works great.
Search Clutch repairs or transmission removal to find a thread where someone was talking about dropping the transmission. I’ve read many threads about their experience.
Then search rear main seal. @Poser has a very good write up in the 40’s section. I used his method and it works great.
- Thread starter
- #5
@Poser is the one I reviewed for the main seal. I have searched removal threads - no joy. I’ll try clutch replacement. I am concerned about how to do it while in the vehicle. Any gotchas or watch out fors. Best to do it with the vehicle on the ground or in the air. Any other while you are in there things to look for. I have a pretty good idea from all my reading, but just want to check all the boxes. Thanks guys!
Is this an FJ60 with manual transmission or FJ62 with automatic transmission?
If you want the removal and install to be as easy as possible (and you definitely do because it’s a very heavy unwieldy unbalanced MOFO) you’ve got to get a decent transmission jack. Harbor Freight has a good one. Don’t buy the cheapest red thing.
Removing transmission while vehicle is on the ground, on 4 wheels is the way to go. The jack will need to roll with the heavy TMS on it so the surface can’t be dirt.
Once the transmission is pulled and dropped, the rear axle on one side is going to need to be jacked way up to be able to slide the transmission out from under the car.
Last time I did mine was in a condo parking garage Lol.
Here’s a picture showing how high I had to jack up the vehicle (after pulling the TMS) to just barely get the jack w TMS out. You can see it off to the left.
If you want the removal and install to be as easy as possible (and you definitely do because it’s a very heavy unwieldy unbalanced MOFO) you’ve got to get a decent transmission jack. Harbor Freight has a good one. Don’t buy the cheapest red thing.
Removing transmission while vehicle is on the ground, on 4 wheels is the way to go. The jack will need to roll with the heavy TMS on it so the surface can’t be dirt.
Once the transmission is pulled and dropped, the rear axle on one side is going to need to be jacked way up to be able to slide the transmission out from under the car.
Last time I did mine was in a condo parking garage Lol.
Here’s a picture showing how high I had to jack up the vehicle (after pulling the TMS) to just barely get the jack w TMS out. You can see it off to the left.
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- Thread starter
- #7
@OSS that is insane doing it in a condo parking lot! My rig is in my signature, a 1984 FJ60. I kind of figured doing it on the floor might be easier with the right jack. Good point on lifting the rear axle, I had to do someone like that removing the engine and transmission from a certain rear engined car. I think my plan is to remove it while on the ground and lift the vehicle with a lift.
If you use the harbor freight 800lb transmission jack it’s pretty easy to pull and install the gear box. But you need to bleed the air and top off the fluid and lube all the moving/threaded parts.
My suggestion is to remove the mounting hardware on the jack down to the bare plate. Then cut a piece of plywood large enough to support the trans. Drill holes where the transmission mount goes. Then you’ll want to support the engine pan and the transfercase with a small jack stand and block of wood. Carefully remove the crossmember from under the transmission. Move the trans jack into place and bolt the rubber mount directly to the jack.
Once the trans is on the jack you can remove the stand from the transfer case. Leave the stand where the oil pan is. Make sure you have a nice piece of wood under the engine oil pan or you’ll break the pan.
If you don’t need the transmission to come out for any repairs you can leave it on the stand under the truck. You just need to push it back a foot or so to access the rear main/clutch.
When you remove the clutch make sure you loosen the bolts gradually all the way around like you’re doing your wheels backwards. Otherwise, you’ll bend the pressure plate and you’ll have issues later on. The FSM talks about this pattern I believe.
Replacing the rear main is pretty straight forward. Pop the old one out. Clean up the surface. I use a very small bead of RTV on the edge of the seal to help it slip in and to seal any discrepancies you might have. I think a 6” pvc pipe cap will fit exactly over the rear main seal to be used as a driver for tapping it in place evenly. Defiantly drain the engine oil before you do any of this or you might paint yourself
When you get it all done and you’re going to stab the transmission back into the pilot bearing take two extra long grade 8 bolts, cut the hex head off, and cut a slot where the hex used to be to accept a flathead. Then install them into the top holes of the transmission/bellhousing. Use them as guide pins to hang the trans on while you get the other bolts started.
I’ll try to post some picks in a minute if I still have them on my phone. Transmission weighs 100 something pounds and the transfer case is nearly as heavy so all together it’s nearly 200 or more. But it’s not as bad as it could if you use the mounting method I describe.
My suggestion is to remove the mounting hardware on the jack down to the bare plate. Then cut a piece of plywood large enough to support the trans. Drill holes where the transmission mount goes. Then you’ll want to support the engine pan and the transfercase with a small jack stand and block of wood. Carefully remove the crossmember from under the transmission. Move the trans jack into place and bolt the rubber mount directly to the jack.
Once the trans is on the jack you can remove the stand from the transfer case. Leave the stand where the oil pan is. Make sure you have a nice piece of wood under the engine oil pan or you’ll break the pan.
If you don’t need the transmission to come out for any repairs you can leave it on the stand under the truck. You just need to push it back a foot or so to access the rear main/clutch.
When you remove the clutch make sure you loosen the bolts gradually all the way around like you’re doing your wheels backwards. Otherwise, you’ll bend the pressure plate and you’ll have issues later on. The FSM talks about this pattern I believe.
Replacing the rear main is pretty straight forward. Pop the old one out. Clean up the surface. I use a very small bead of RTV on the edge of the seal to help it slip in and to seal any discrepancies you might have. I think a 6” pvc pipe cap will fit exactly over the rear main seal to be used as a driver for tapping it in place evenly. Defiantly drain the engine oil before you do any of this or you might paint yourself
When you get it all done and you’re going to stab the transmission back into the pilot bearing take two extra long grade 8 bolts, cut the hex head off, and cut a slot where the hex used to be to accept a flathead. Then install them into the top holes of the transmission/bellhousing. Use them as guide pins to hang the trans on while you get the other bolts started.
I’ll try to post some picks in a minute if I still have them on my phone. Transmission weighs 100 something pounds and the transfer case is nearly as heavy so all together it’s nearly 200 or more. But it’s not as bad as it could if you use the mounting method I describe.
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These are the best pics I have right now. Last time I did this I was in a public parking space and I was on a time crunch and didn’t take a lot of good photos. But you can kinda see how I mount the transmission to the jack here using the plywood. If you want to take the thing out from under the truck you’ll want to do like @OSS suggested and raise the axle. I did the front passenger side and it slides out just inside the wheel well. I may have even removed the wheel itself for clearance.
In this last pic above, if you look to the top of the image you’ll see the long guide bolts I’m talking about. The very last pic below is rear main seal and pilot bearing. If you’re gonna do all this work you might as well change the clutch, pilot bearing, throw out bearing… etc… while you’re in there…
@t6dpilot Are you sure the RMS is leaking? A leaking valve cover gasket and/or oil pan gasket can mimic a RMS leak. I'd rule those out first before going to the effort to replace the RMS. Other considerations are that if you do pull the transmission to replace the RMS also replace the pilot bearing and check the condition of the flywheel and clutch disc.
g-man
SILVER Star
I also used Poser's method to remove the RMS. Here is his thread outlining this: Rear main seal removal - https://forum.ih8mud.com/threads/rear-main-seal-removal.814649/
Here is a link to the chassis and body FSM in the Resources section. FSM - 1984 - 1990 Repair Manual, Chassis/Body - https://forum.ih8mud.com/resources/1984-1990-repair-manual-chassis-body.1/ go here and download this! Then find the sectons on the clutch and the MT...manual transmission.
You can find some basic info about removing the trans and clutch.
Here is a link to the chassis and body FSM in the Resources section. FSM - 1984 - 1990 Repair Manual, Chassis/Body - https://forum.ih8mud.com/resources/1984-1990-repair-manual-chassis-body.1/ go here and download this! Then find the sectons on the clutch and the MT...manual transmission.
You can find some basic info about removing the trans and clutch.
- Thread starter
- #12
@cps432 thank you for that detailed description. I plan to remove both the transmission and transfer case together. The plan is to drop the oil pan also per the @Poser RMS replacement method and also do the pan gasket. I assumed that the engine mounts are sufficient to support the engine with the trans out, correct? Obviously, can't replace the oil pan gasket with a jack stand under it. Appreciate your post - big help.
@Godwin yes, I am pretty sure it is the RMS leaking. The shop that did some work for the PO told me about it and I have checked. Drips come from in between the oil pan and transmission, but I plan to clean everything up and confirm before disassembly.
@Godwin yes, I am pretty sure it is the RMS leaking. The shop that did some work for the PO told me about it and I have checked. Drips come from in between the oil pan and transmission, but I plan to clean everything up and confirm before disassembly.
g-man
SILVER Star
Leave the exhaust bolted up even though the FSM says to unbolt it. You can get the trans/t-case past it. AND it will help to support your engine. Otherwise the engine will lean back on the engine mounts ...making it harder to re-connect the transmission and the exhaust.
There is one more potential oil leak location that may lead you to think it's a RMS leak until you pull things apart. On the rear of the block, left side and high, is a plug that may loosen and leak oil. You cannot see it well or access it until you pull the bell housing. My 2F is leaking in this spot and I've attempted to correct it once, now I just live with it.
