48RE Performance Transmission Rebuild

[LAmiller]

Originally Posted by YOUNG GUNS15

Failed at roughly 230-250psi line pressure, it now has a stock servo and a billet band from Suncoast. 48re with pcs/ATS valvebody

This is usually the results of a 2-3 locked shift bind up. With a 48re 5.0 lever we have seen this 3 or 4 times. Running the TCS Billet servo (not the Sonnax, those bind up worse then stock) with the stock spring, and the 4.2 ratio lever, we have not had one band failure with the BW Band.

When a bind up happens, the 2nd gear band is still applied when the 3rd gear clutch comes on and if neither slips, either the band will break or it breaks an intermediate shaft when the converter is locked and cannot absorb the bind up.

Lavon

[GOT-Torque]

awesome thread.

[YOUNG GUNS15]

Originally Posted by LAmiller

This is usually the results of a 2-3 locked shift bind up. With a 48re 5.0 lever we have seen this 3 or 4 times. Running the TCS Billet servo (not the Sonnax, those bind up worse then stock) with the stock spring, and the 4.2 ratio lever, we have not had one band failure with the BW Band.

When a bind up happens, the 2nd gear band is still applied when the 3rd gear clutch comes on and if neither slips, either the band will break or it breaks an intermediate shaft when the converter is locked and cannot absorb the bind up.

Lavon

I agree, those sonnax Servos are a pain to deal with. That is the servo that was in this transmission at the time of failure with a 4.2 lever. Our failure was a tuning issue/ tps loosing its ground and commanding full line pressure. I have the line pressure tuned in MUCH better. It was a steep learning curve

[Gwoody]

Originally Posted by YOUNG GUNS15

Failed at roughly 230-250psi line pressure

Running that much pressure have you ever had issues over centering or collapsing the Belleville return spring in the forward clutches?

[YOUNG GUNS15]

Originally Posted by Gwoody

Running that much pressure have you ever had issues over centering or collapsing the Belleville return spring in the forward clutches?

yes, it didn't take it out immediately but the piston did eventually over extend and catch the lip seal due to a busted/weakened belview spring.

[Tobin]

Awesome thread.

I had the DNJ/GM sensor in my trans for years w/o a problem and then I just got my transmission rebuilt and the builder used the Borg Warner one. Not sure how it will hold up or how it even works as the trans is pretty much a paper weight right now....


Tobin

[murphy41]

Originally Posted by YOUNG GUNS15

yes, it didn't take it out immediately but the piston did eventually over extend and catch the lip seal due to a busted/weakened belview spring.

Hense the reason mine has a billet Bellview retainer in it.

[TMONEYDIESEL]

I lived in belvue once

[murphy41]

Originally Posted by TMONEYDIESEL

I lived in belvue once

Bring back some memories or ?

[Red Sleeper]

Originally Posted by LAmiller

This is usually the results of a 2-3 locked shift bind up. With a 48re 5.0 lever we have seen this 3 or 4 times. Running the TCS Billet servo (not the Sonnax, those bind up worse then stock) with the stock spring, and the 4.2 ratio lever, we have not had one band failure with the BW Band.

When a bind up happens, the 2nd gear band is still applied when the 3rd gear clutch comes on and if neither slips, either the band will break or it breaks an intermediate shaft when the converter is locked and cannot absorb the bind up.

Lavon

Hm. This has me second guessing my Sonax servo and accumulator piston now that you mention this binding issue. I have the stock ratio lever and wondering if I should up to the 4.2 now.

I wish this thread would have started about 5 months ago. Might have saved me some head aches.

[12vCumminsFTW]

Originally Posted by murphy41

Hense the reason mine has a billet Bellview retainer in it.

Now I'm curious. More info on this or is it secret squirrel stuff? That silly return spring is like the only thing keeping me from raising the pressure a bit more.


Sent from phone

[Big Blue24]

The older style (47rh/47re) belleville spring will handle 225 psi, the newer 48re style spring which is very similar to the ancient 727 belleville spring will handle 200 psi.

[12vCumminsFTW]

Ok I'm still confused, the one I have looks like this. So this is the newer spring thats weaker? http://www.google.com/imgres?imgurl=...tart=0&ndsp=17

[Gwoody]

Here is the heavier older spring http://transpartsdirect.com/popup_image.php?pID=11407

but it takes more pressure to apply it so it's kinda a trade off.

[murphy41]

Originally Posted by 12vCumminsFTW

Now I'm curious. More info on this or is it secret squirrel stuff? That silly return spring is like the only thing keeping me from raising the pressure a bit more.


Sent from phone

To be honest I'm not even sure. The guy that built my trans had them made up with his logo engraved in them. I just know it works with the higher line pressure. You probably could get away without one like Will said. But I have a spare one in my tool box, and its a piece of mind knowing I don't have to worry about it.

[Jim Fulmer]

This is the original intent for the forums, seems the last few years it has been nothing but a circus show, thanks for putting up real material!

Jim

[Chrisd91]

Originally Posted by TMONEYDIESEL

I lived in belvue once

Bellevue? My condolences, that's on the wrong side of the mountains

Will, you must have amazing patience for all these pics! I set out to take pics when I did my trans and only made it through the VB before I have up

[Tobin]

Any more pictures of the assembly?

Tobin

[Big Blue24]

Main Case Rebuild

First off drill a hole in the rear of the case to promote additional lube flow to the rear sprag:







View from inside case:


Next remove low/reverse servo and lever by removing rod holding lever in-place:







New sonnax center pin and low/reverse servo cup:


New Sonnax low/reverse servo parts on left:






Install new seals from rebuild kit:


Lube with trans fluid and install:






Install new seals provided in rebuild kit and set lever and shaft aside for later final install.

[Big Blue24]

Next remove the 2nd gear servo and lever, start by removing the 1/4" pipe plug inside the bell housing to gain access to the lever pivot rod:









Compress the 2nd servo cover and remove the snap ring and servo components:






Install new Sonnax upgraded 2nd servo cover:


Sonnax cover has added groove for a sealing o-ring to help clean-up the 2-3 gear shift.


Tear down the servo to replace the inner o-ring seals with new ones provided in rebuild kit.









Upgraded 4.2 ratio lever on the left:


Install lever, pivot rod, and replace the 1/4" pipe plug complete with sealant.