4L85E mystery leak

[L31MaxExpress]

Now I get the fun of pulling the 4L85E. Either the input seal, pump to case or pump bolt seals are leaking. Steady drip of fluid after the engine has run for a few minutes from the converter dust shield. If it is mechanical, if it is not one thing it is another.

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[L31MaxExpress]

I am considering going through this transmission when I pull it. Any thoughts? My plan is a Sonnax HP kit in the valve body and internally dual feeding it. If I go with the Sonnax kit does the added line to lube hole still need to be drilled? I feel it is good insurance to do the lube system modifications for the roller, sprag clutches. Maybe use the earlier style overdrive roller clutch if it drops in without machine work. I will rollerize the output since I can easily obtain those parts. I do not see a reason to go with anything special on the clutches or steels. I also feel like the stock geartrain parts are more than adequate for the torque I am making. No need for strongers shafts or the extreme hubs or anything crazy like that. I would love a 2.96 or 2.75 1st gear, but I see no reason to spend that kind of $$$ given I will be going to a 6L90E in a year or two anyway. I want to keep the unit as a spare for the Tahoe or put it in the G20 van later, so it makes sense to me to make it solid for the future. Neither the Tahoe or the G20 weigh what the Express van weighs, so 2.48 1st is perfectly adequate for them.

 

[NickTransmissions]

I am considering going through this transmission when I pull it. Any thoughts? My plan is a Sonnax HP kit in the valve body and internally dual feeding it. If I go with the Sonnax kit does the added line to lube hole still need to be drilled? I feel it is good insurance to do the lube system modifications for the roller, sprag clutches. Maybe use the earlier style overdrive roller clutch if it drops in without machine work. I will rollerize the output since I can easily obtain those parts. I do not see a reason to go with anything special on the clutches or steels. I also feel like the stock geartrain parts are more than adequate for the torque I am making. No need for strongers shafts or the extreme hubs or anything crazy like that. I would love a 2.96 or 2.75 1st gear, but I see no reason to spend that kind of $$$ given I will be going to a 6L90E in a year or two anyway. I want to keep the unit as a spare for the Tahoe or put it in the G20 van later, so it makes sense to me to make it solid for the future. Neither the Tahoe or the G20 weigh what the Express van weighs, so 2.48 1st is perfectly adequate for them.

- Sonnax PR valve: no line to lube hole (do all the other lube mods)
- Sonnax LB1-4L80E
- Earlier roller clutch usable if you swap in an earlier OD planet (only the outer race changed)
- Rollerize the rear of the case
- replace all bushings
- replace all bonded pistons
- BW or Raybestos stock frictions are fine - replace steels as needed otherwise just prep your existing ones
- replace all one way clutches (prep the int outer race w/400 grit sand paper)
- replace all electronics
- Install a wide forward drum bushing (make sure your drum's inner dia has no sealing ring grooves cut in or bore/ream and sleeve it if so)
- Sonnax 1-2 and 2-3 shift valve springs, AFL and TCC valves
- check pump gear face to body working surface - machine if needed / replace gear set if necessary
- use an A518 direct clutch snap ring in place of the stock intermediate clutch snap ring (they are selective and come in thicknesses ranging from .068-.120 or so)
- Internally Dual feeding the direct clutch is up to you but if HP/TQ is under 450 its not necesssary.

- Optional unless hp=> 500-550 and street strip/high rpm: Billet rollerized forward hub

- DO NOT INSTALL A TRANSGO HD2 kit
- DO NOT INSTALL ANY "PRESSURE RELIEF mechanism made by Transgo or anyone else

Ill edit to add if i think of anything else.
Reply back with any ?s

 

[L31MaxExpress]

Power is ~500 hp and 520+ tq. It will not see the high side of 6,000 rpm. If it goes behind my 8.1L in the Tahoe, it will see close too 600 ft/lbs. Dual feeding the direct seems to make sense to me considering I have a fair amount of power and do tow up to 8,000 lbs or so with it. The van itself is nearly 7,000 lbs empty.

The rollerized hub might not be a bad upgrade, they are not particularly expensive, especially if you feel 500-550 hp is the upper limit on the stock one. It is not a Street/Strip kind of build but I do not hesitate to put the pedal down towing as needed. Plenty of added stress there. The converter was built to make a lot of torque multiplication.

This should be a 4L85E based off the external information, it should have the 5 pinon jobs inside. Would it be a backwards step to install the earlier planet and roller clutch in this unit?

Also on the electronics, Brown solenoids not White IIRC.

 

[NickTransmissions]

Power is ~500 hp and 520+ tq. It will not see the high side of 6,000 rpm. If it goes behind my 8.1L in the Tahoe, it will see close too 600 ft/lbs. Dual feeding the direct seems to make sense to me considering I have a fair amount of power and do tow up to 8,000 lbs or so with it. The van itself is nearly 7,000 lbs empty.

The rollerized hub might not be a bad upgrade, they are not particularly expensive, especially if you feel 500-550 hp is the upper limit on the stock one. It is not a Street/Strip kind of build but I do not hesitate to put the pedal down towing as needed. Plenty of added stress there. The converter was built to make a lot of torque multiplication.

This should be a 4L85E based off the external information, it should have the 5 pinion jobs inside. Would it be a backwards step to install the earlier planet and roller clutch in this unit?

Also on the electronics, Brown solenoids not White IIRC.

Your reaction and output carriers (front and rear planets in the back of the case) will have five pinion gears each however I believe all the OD planetary assemblies all had four pinions...If you do have a five-pinion OD carrier and want to swap to the earlier, larger OD roller assembly, you just need to swap the races with an earlier OD planetary assembly...Just use a hammer and drift; be careful not to damage any planetary gears but apart from that it's fairly straight forward. It's been quite a while since I've seen a 4L85E so can't remember if the OD planet had 5 pinions...Id do the rollerized forward hub given your power levels and application.

I'd be tempted to throw some Raybestos Stage One frictions into the direct clutch (you should be able to buy them individually) - HE BW or Raybestos will be fine for everything else...

New PWM and/or shift solenoids may or may not have the same color connectors as OEM but will work just the same.

Perhaps @tayto can share his perspective if he passes by the thread.

 

[Schurkey]

- DO NOT INSTALL A TRANSGO HD2 kit
- DO NOT INSTALL ANY "PRESSURE RELIEF mechanism made by Transgo or anyone else

Curious about this.

I bought a Transgo HD2 kit for my '97 K2500, but I've completely failed to install it. I have heard other folks say to install the kit but omit Steps 4 & 5, which is the pressure relief valve.

Aside from the pressure relief mod, what else in the HD2 kit has you concerned?

 

[NickTransmissions]

Curious about this.

I bought a Transgo HD2 kit for my '97 K2500, but I've completely failed to install it. I have heard other folks say to install the kit but omit Steps 4 & 5, which is the pressure relief valve.

Aside from the pressure relief mod, what else in the HD2 kit has you concerned?

The stupid-ass sandwitch style riveted multi-layer spacer plate. The HD2 kit uses it to dual feed the direct clutch via that plate but its design lends itself to cross leaks between it and the vb/case. Besides you can do everything that kit provides for and more without it if the trans is apart on the bench, including internally dual feeding, A518 direct clutch snap ring for the 4L80E/TH400 intermediate clutch snap ring, lube mods, Sonnax boost and TCC reg valves plus 1-2 and 2-3 valve springs for a lot less.

 

[tayto]

x2 on the Transgo HD2 kit, throw it in the trash!

The only time I use the sonnax lube regulated PRV is if I am doing a "shift kit" without pulling the trans..it's a nice piece but drilling the pump is a lot cheaper and more adjustable.

I like the LB1 valve as well, but don't use the supplied spring just run your OE spring. this is good to 700-800 HP from what i'm told.

when dual feeding you may want to block the 3rd accumulator. i wouldn't block the 4th accumulator.

very important and not mentioned yet. check your AFL valve or just take it to a transmission shop and get them to ream it. if you can get the valve body vac tested even better. there are a few of the sonnax oring plugs that will help.

 

[NickTransmissions]

x2 on the Transgo HD2 kit, throw it in the trash!

The only time I use the sonnax lube regulated PRV is if I am doing a "shift kit" without pulling the trans..it's a nice piece but drilling the pump is a lot cheaper and more adjustable.

I like the LB1 valve as well, but don't use the supplied spring just run your OE spring. this is good to 700-800 HP from what i'm told.

when dual feeding you may want to block the 3rd accumulator. i wouldn't block the 4th accumulator.

very important and not mentioned yet. check your AFL valve or just take it to a transmission shop and get them to ream it. if you can get the valve body vac tested even better. there are a few of the sonnax oring plugs that will help.

Central Valve Bodies out of Oklahoma makes drop in oversized AFL valves ($25 or so) for the 4L80 and 60. No reaming/drilling and they do a good job revitalizing the AFL on most units. I mentioned it in my initial reply above but it bears repeating/reinforcing as its a common problem in those units and the 4L60Es to a lesser extent...

 

[tayto]

Central Valve Bodies out of Oklahoma makes drop in oversized AFL valves ($25 or so) for the 4L80 and 60. No reaming/drilling and they do a good job revitalizing the AFL on most units. I mentioned it in my initial reply above but it bears repeating/reinforcing as its a common problem in those units and the 4L60Es to a lesser extent...

yea i forgot about that option. I've heard of others using but have not used myself. whatever works as long as it vacs good!