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48re pressure recommendations

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5.9 w/ Auto transmission no top end just dies

Hey all,

I have recently had some transmission issue and have gotten them resolved. This is on a 2003 2500QCLB 4x4 with the 5.9 HO and the 48re trans. My question now is what the appropriate pressures should be. I am currently at 88psi at the accumulator at idle. I am going to get a 300psi gauge to check the rest of the pressures later this week. The trans has stock internals with the exception of a billet accumulator, billet intermediate servo cover, billet anchor and band strut, and a super shift kit and valves as recommended by tim holt. It also has a superior boost cover with the hole enlarged to .096 and the check ball in the cooler has been removed. The engine is the 305ho with a custom tune with hptuners that should be add an additional 80-90hp. I am just trying to make sure I dont jack the pressure to high. Where should they be with the above mods?
 
80-90 psi at idle is fine. Max pressure will be when you advance the TV lever all the way, should be up around 130 at idle. When you drive it you should pressures in lockup and OD jump to the 160-180 range.
 
Thanks cerberusiam! I was hoping you were going to comment. I will disconnect the TV cable and advance it fully by hand at idle and see where its at. I am also going to hook up the gauges and drive and see where everything else is at. It looks like besides idle just follow the test procedures from the manual but do it on the road instead of a lift is that correct?
 
Thanks cerberusiam! I was hoping you were going to comment. I will disconnect the TV cable and advance it fully by hand at idle and see where its at. I am also going to hook up the gauges and drive and see where everything else is at. It looks like besides idle just follow the test procedures from the manual but do it on the road instead of a lift is that correct?
 
Hey Cerb, I have not had a chance to check the pressures yet but I am having another issue that I am hoping you have some suggestions on. I put a shift kit in and some accompanying parts and adjusted the bands. The both bands were torqued to 72 inlb and the front was backed off 1.75 turns and the rear was backed off three turns. The issue I am having is that I have a large amount of slipping in reverse. I have retightened the rear band a 1/4 turn at a time until it caused a shift bind and a second gear start. I backed it off 3/4 of a turn and it is shifting and holding fine in all forward gears and hard acceleration. When I put it in reverse it shifts solid into reverse and backs up fine but if you give it any throttle it will slip pretty easily. I took it out on a hill and backed up against the hill and the first time it slipped until I let of the throttle a little and then it clunked like something caught and held good. I tried it again and it just slipped. Any ideas on what is causing this?
 
Leave the setting at 3 turns and find the problem. Does manual first fell solid with no slipping? If so your OD direct clutch pack is likely about done. If not direct clutch pack is hosed.
 
Well, reset thebrear band to 3 turns, reverse is the same maybe a little worse. Now there is a 1-2 shuttle shift. I tried adjusting the cable to take out the shuttle without success. It is possible that 3rd and 4th are slipping under moderate throttle. It does engine brake if I go into M1. At this point I am assuming that the OD Direct clutch is shot. No idea about the shuttle shift and why it showed up now. I am about to lose my mind with this thing
 
If both 3rd and 4th AND reverse slip it is likely the direct clutch pack. Rear band has no effect on the auto 1-2 shift, rear band is not applied in auto 1st. If you have shuttle shift probably slippage due to pressure drop in the circuits.
 
Can I just rebuild the OD unit? I really need this truck functional and I don't really want to pull and rebuild the entire trans.
 
Sorry Cerberusiam, are you refering to the front clutch? I looked at the chart in the FSM and it shows the front clutch applying in 3rd, 4th, and reverse. The FSM is a little confusing in that it refers to it as the front clutch in the chart but then calls it the direct clutch later. I confused it with the OD direct clutch. If I air test the front clutch will I be able to hear air leaking if it is shot?
 
Yeah, easier to talk about direct clutch (front clutch) and forward clutch (rear clutch) packs than the other way. The forward clutch pack is not really the rear clutch as the OD directs are at the back of trans. Easier to talk function; direct, forwards, OD brake, OD direct in that order from front to rear.
Since the OD is an add on ECM controlled you have to separate the discussion again. Forward clutch pack is on in any forward gear, direct clutch pack is applied in D and R. OD will only apply in D so direct will always be on at that point.


You need a rubber nose air gun to seal around the port but you can air check it. It might leak, it might now depending on what is actually worn and how bad. If it is worn bad enough and over extending the apply piston it is cutting little notches in the seal and will leak when air is applied.
 
Well, went to take my daughter to school this morning and got halfway there and no forward or reverse. It was shifting very softly as we drove and then would not move at all. If you shut it off and let it sit it will drive for a very short time and then stop moving. The engine just revs and nothing happens. Shut it off and let it sit....same story. Got it home an put a gauge on the accumulator and when you start it the pressure goes to 88psi and then starts dropping until it hits zero. It sounds like the pump stops working but there is plenty of fluid. Pulled the pan off and there are a lot of shiny metal shavings on the magnet and in the fluid that is dripping off the valve body. Any ideas on the loss of pressure? Regardless it sounds like it is time for a rebuild. Any recommendations on a kit. Don't need anything exotic. Will not ever be putting anymore power to it than the tuner will provide and only tow an 8000lb boat in the summer. Thinking just a standard kit with raybestos GPZ clutches.
 
Looks solid. I would do the TCS no leak servos for the low\reverse and intermediate locations. I would also replace the sprag clutch in the rear of the case. It might look good but they fatigue and when they grenade it is messy. Do new snap rings for everything also.
 
Will I need an endplay and OD shim kit? I have also seen where some people order a complete bushing kit and a thrust spacer kit? Sorry for all the questions, just trying to make sure I have everything when I tear it down.
 
Hey Cerb, thanks for all your help with this. I have ordered a converter from DPC and a stage 2 rebuild kit from Dynamic Transmission. Jon was incredibly helpful and put together everything I needed. Thanks again for your help!
 
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