Rear Main Oil Seal

[Larryjb]

Based on MJReynolds' experience ( https://www.tahoeyukonforum.com/thr...e-2007-tahoe-5-3l-135-000-miles.116461/page-8 ), I have decided to do my own rear main oil seal. He did not have to remove the transfer case, but I'm nervous about balancing the transmission and transfer case on a transmission jack with a jack supporting the transfer case. Also, if I get it out and find I have to remove the transfer case anyway, I might as well remove it first.

There are lots of videos on this, but they all omit important steps. I suspect part of the reason is the added time consuming process of video recording everything. Often there is no mention of fluids involved, removing all the electrical connectors from the transfer case, etc etc etc. By looking a 2-3 videos so far, I have a more complete picture, but I will try to document each phase of the process here to provide a more complete process.

Here is a general outline:

1. Drain transmission, torque converter (if there is a plug on the converter).
2. Drain transfer case.
3. Remove drive shafts.
4. Remove exhaust Y-pipe.
5. Remove cross member for transmission mount.
6. Remove transfer case.
7. Remove transmission.
8. Remove flexplate.
9. Remove rear main seal.

Many of these steps are more complicated and time consuming than they appear. MJReynolds took about 11 hours total, but he did not remove the transfer case, or exhaust. I assume this will add a few hours to my job.

So far, the extra tools I am purchasing for this job are:

1. transmission jack: https://www.princessauto.com/en/detail/1-100-lb-low-lift-transmission-jack/A-p8667875e . It's pretty inexpensive, but if MJReynolds was able to get it out with something like this: https://www.harborfreight.com/450-lbs-low-lift-transmission-jack-61232.html , on uneven ground, with hardly a bleep, I think I can do it with the tool from Princessauto.
2. High torque impact: https://bcfasteners.com/shop/milwau...ue-impact-wrench-1-2-pin-detent-with-one-key/

 

[drakon543]

i did this on my 97 tahoe with a buddy with just a floor jack but a transmission jack would have made things 100xs easier. if you pull the transmission gently trying to make sure the torque converter doesn't come off it technically doesn't have to be drained. it is an added benefit to getting a more thorough transmission fluid change tho. draining the transfer case and transmission will make seperating the 2 a cleaner less messy job.

 

[Larryjb]

i did this on my 97 tahoe with a buddy with just a floor jack but a transmission jack would have made things 100xs easier. if you pull the transmission gently trying to make sure the torque converter doesn't come off it technically doesn't have to be drained. it is an added benefit to getting a more thorough transmission fluid change tho. draining the transfer case and transmission will make seperating the 2 a cleaner less messy job.

Not to mention the fact that the transfer case fluid is probably original!

 

[OR VietVet]

If there is no drain plug for the torque converter then when you unbolt from the flex plate and as you look at it from the front, turn it clockwise and push back at it will settle back deeper in the bell housing. I have done this and kept it level as I moved back with no spillage. If you are afraid it might work it's way back forward and cause problems I have SEEN where a guy once used a ratchet strap and made a loop that he wrapped around the converter center snout and then ran the strap under the trans to the back and attached and then ratcheted it just to the point of tight and it stayed in there. Too much pressure could **** the converter and damage that front seal. When you are ready to reattach at the flex plate just pull and spin counter clockwise to mate them up. Personally, if it was me I would remove it and drain in the beginning.

Note: I have never done this on a 4L60E so maybe Rockola1971 has a better recommendation.

 

[rockola1971]

You really arent saving time by pulling down the tranny and Tcase as one unit. All it does is make one very awkward assembly to balance while bringing it down. The Tcase is very heavy hanging off the rear of the tranny. Tcase can be dropped with an air ratchet in 15mins and drain its fluid. No sense in taking a chance of dropping the converter or worse it screwing up the tranny pump or its bushing. Me personally I would remove the converter before lowering the tranny all the way down and dump its fluid. Replace the front seal anyway. They are cheap. Youd feel real stupid to do all the work you are doing to have to redo it 1 week later because a $4 front seal is leaking or worse yet you walked the pump bushing forward and now its creeped further forward and is blocking the tranny fluid return which blows your front seal out. What a mess....dont do it.

 

[Larryjb]

You really arent saving time by pulling down the tranny and Tcase as one unit. All it does is make one very awkward assembly to balance while bringing it down. The Tcase is very heavy hanging off the rear of the tranny. Tcase can be dropped with an air ratchet in 15mins and drain its fluid. No sense in taking a chance of dropping the converter or worse it screwing up the tranny pump or its bushing. Me personally I would remove the converter before lowering the tranny all the way down and dump its fluid. Replace the front seal anyway. They are cheap. Youd feel real stupid to do all the work you are doing to have to redo it 1 week later because a $4 front seal is leaking or worse yet you walked the pump bushing forward and now its creeped further forward and is blocking the tranny fluid return which blows your front seal out. What a mess....dont do it.

Yeah, I could see myself dropping the entire transmission/transfer case if I removed them together. But you say it can be dropped in 15 minutes. That's more like 2 hours for me, but it will be worth my efforts for sure.

How difficult is the front seal to remove? Is it worth it for me to get a seal remover? (about $15 Cdn)

 

[rockola1971]

Yeah, I could see myself dropping the entire transmission/transfer case if I removed them together. But you say it can be dropped in 15 minutes. That's more like 2 hours for me, but it will be worth my efforts for sure.

How difficult is the front seal to remove? Is it worth it for me to get a seal remover? (about $15 Cdn)

You can pop the front seal out with a flathead screwdriver. Tap the new one in with block of wood jumping back and forth on sides of seal or find something make shift. there are vids on youtube.

 

[Larryjb]

Thanks, that looks easy enough.

Starting to collect parts. Shipping to Canada through rockauto will take a few extra days.

Bought a new creeper today. I got tired of using my 30 year old Canadian Tire creeper that would roll every direction except the one you wanted.

 

[ivin74]

You can pop the front seal out with a flathead screwdriver. Tap the new one in with block of wood jumping back and forth on sides of seal or find something make shift. there are vids on youtube.

What front seal are y'all talking about?

 

[Larryjb]

I assume Rockola is referring to the transmission pump seal, or the seal that is in the front of the transmission and is visible when you remove the torque converter.

 

[Larryjb]

I've been trying to figure out what is better, Fel-Pro or ACDelco. Normally, I go with Fel-Pro because they have made very good gaskets for everything else I've used. Normally, the Fel-Pro cost is close to the ACDelco, maybe a little less. However, the Fel-Pro cost for the rear main is MUCH cheaper. Would this be a case where ACDelco is the better gasket? Or is Fel-Pro still better even though it's a lot cheaper?

As of March 2020:
Fel-Pro rear main set (includes cover plate seal) (BS40640) $16.72
ACDelco: rear main seal (89060436) $21.79 + cover plate seal (12639249) $18.69

 

[rockola1971]

What front seal are y'all talking about?

The one you should always replace anytime you have a transmission yanked down...the transmission front seal which is what the snout of the torque converter passes through.

 

[Larryjb]

One further question:
I will be replacing the oil pan gasket, oil pickup gasket, and the oil cooler blockoff plate gasket.

It appears that the gasket used for the block off plate is the oval style gasket. Is there any benefit to switching to an oil cooler? I do tow a camping trailer a few times a year.

 

[Larryjb]

So far this is what is a list of parts I plan to order tomorrow:

1. Engine oil pan gasket
2. Engine oil cooler gasket
   
3. Engine oil pump seal (engine oil pick up tube seal)
4. Rear crankshaft seal (includes cover plate gasket)
5. Torque Converter shaft seal
6. Transmission filter and pan gasket
7. Transmission mount (they're cheap, why not get one)
8. Transfer case adapter gasket

Other than fluids, have I missed anything?

 

[drakon543]

take a look at the design of the real seal also. i know with my 97 they made the replacement seal slightly beefier probably to take up and wear. fel pro maybe cheaper because its a thinner original design versus an updated design.

 

[Rocket Man]

When I did mine I went with the ACDelco rear seal that comes pre installed in the rear cover with gaskets and everything included. It makes it easier to get installed correctly. I didn’t want to go through all that work and chance the seal not being centered perfectly causing it to leak in a month.

 

[latvius]

I used one of these to make sure the seal is centered. (Actually I bought the billet set).

https://www.saccitycorvette.com/AlignItTools.html

They have a video on how to install the rear main plate, it's pretty good.

I also bought the billet barbell, don't know if it will make a difference but I had the trans pulled so why not.

Also in your list of things to do I did not see pulling the crossmember under the oil pan. Soak your exhaust manifold bolts in penetrating oil days before as well.

You'll need a long extension for the impact to get the bell housing bolts. Also I rerouted the transfer case vent tube which allowed me to delete the holdown on the top of the transmission bell housing. (would have been a pain to try and keep it since it is hard to reach).
You'll want to jack up the truck high to get the trans out (if you are pulling it all the way) I bought 10 ton stands from Jegs to put under the front. I replaced my trans when I did the rear main so this may not be necessary BTW.

Oh yeah mark your transmission cooler lines so you know which one goes where (inlet and return).
Put all the bolts in individual marked ziplock bags, makes it much easier on the reassembly.

If you're planning on doing the corvette servo mod now is the time so you can see what you are doing when the trans is down.

That's all I can think of, hope that helps!

 

[Larryjb]

When I did mine I went with the ACDelco rear seal that comes pre installed in the rear cover with gaskets and everything included. It makes it easier to get installed correctly. I didn’t want to go through all that work and chance the seal not being centered perfectly causing it to leak in a month. View attachment 242560

I've seen this part a few times, but it doesn't seem to be widely available. If it is, it would likely be very expensive here in Canada.

 

[Larryjb]

Richard,
Interesting tool there. That is the first time I've seen that method used in any video. Most seem to install the seal into the plate first, leaving the plastic insert in place. Then they attach the plate and the seal self centers. Is this a bad method?

 

[OR VietVet]

Great time to check and do the u-joints, if needed, while the shafts are dropped. Seals where they slide back in as well. In your parts list I don't see these.