2006 48RE weak reverse

[deereman01]

2006 Ram CTD 4x4 with 48RE, 167,xxx miles. Brought it home with a blown #4 injector line. I know it would pull on the gooseneck with a lot of throttle, and reverse seemed alright, but didn't drive it much. Fixed the fuel line, and on to the trans. Park would hang so bad we thought we would break the column shifter. Previous owner installed Derale pan. Dropped pan, found glittery fluid, pulled valve body, installed Georend bullet detent kit. Reinstalled valve body, and filled with new ATF4, and there's a weak reverse or 1st with engine braking. Put a transducer on the rear servo port, and I'm seeing 180-190 in reverse at 1500 rpm, but the truck still won't pull in 4 low. 1st has no engine braking, pressure ranges from 65 at idle to 70-72 at 1800 rpm. Removed the TTVA, ran the throttle lever around by hand, and pressures go up to 285-290.

 

Drove it around the block, and I have this shudder in forward at really low rpms, and the same shudder in reverse, and it won't back up a slight incline. 

I turned in the screw under the throttle valve a few rounds, because as my wife would step on the throttle, it wouldn't push the throttle valve in all the way. Pressures came up some, but it still doesn't feel right. 

 

Didn't take anything else on the valve body apart except the manual valve to put in the bullet detent, so I'm stumped here. I also made a mistake and didn't gauge the pressures before, since it was only a park detent issue. Anyone have some really good ideas, or is it toast? 

[Mopar1973Man]

I'll tag @Dynamic and get him in here he'll know the answer to this puzzle. 

[AH64ID]

1st won't have much engine braking due to the torque converter not being locked. 

 

Any tuning on the truck?

 

The few stock 48RE's I've driven are pretty weak in 1st and R due to tuning. 

[deereman01]

Thanks Mopar. Saw Dynamic on here a bunch, seems real knowledgeable. 

 

Truck is stock. No tunes. Minor upgrades like Derale deep pan, but best I can tell, no major updates.

Old man I bought it from just drove it a little. His son owned it before, and can't remember any major upgrades, mostly just the deep pan for towing his travel trailer.

 

[deereman01]

Next update. Got back under truck to do pressure testing, reverse will build up to about 190 or so, and the trans quits pulling backwards. When you let off, and it gets back under 190, it will surge backwards.

 

Also, did a forward gear pressure test after that, and hooked to a heavy load. Went about 5 feet, and lost all pressure in forward and reverse. Fluid level looks ok, not burnt. No vehicle motion at all now. Any ideas?

 

[Dynamic]

Your pressures, while somewhat on the low side, should work. It sounds like you could have a broken rear band or something broken in the servo. It would be tough to give an exact diagnosis without actually looking at it, but either way, you're looking for a problem with the rear band/servo in my opinion.

 

FWIW, there are no electronics involved in either Reverse or Manual Low. Both are 100% hydraulic in function.

[deereman01]

@Dynamic

Took the trans out, rear band had ground up the rear drum. Also found gasoline clutch packs in the overdrive sections (5 disk instead of 6 per ATSG manual). Got it all rebuilt, and set upright on the workbench, and applied air to the rear servo port through the 1/8 NPT, and I have air leaking between the valve body and the separator plate? Is this probably what caused my issues? Have you seen similiar before?

[Dynamic]

You can't apply the band by blowing air into the pressure port. The air will simply exhaust out of the valve body, as you are seeing.

 

BTW, 5 discs in the OD brake is stock on a 48RE.

[RobD]

On 11/7/2018 at 7:30 AM, Dynamic said:

 

BTW, 5 discs in the OD brake is stock on a 48RE.

I spent a good hour during my rebuild trying to find out why mine had only 5 as well...

 

I think the ATSG manual shows how it should have been built, not how it was built.

[deereman01]

@RobD

That's probably exactly right. My wife was helping put stuff together, and even mentioned that it didn't look right.

 

@Dynamic

Trans is reassembled, put back in truck. New valve body, new TC, etc. All new clutch packs, new rear band, new servos, new rear drum. No reverse, even in 4 lo. Any other ideas? I've been through it with a fine tooth comb, and I'm not coming up with anything else.

Issue wasn't there before I pulled valve body to put the detent bullet in. Forward pulls fine, all the way from D to manual 1. Havent driven the truck so nothing should be broken yet. Just no reverse. Pressure in reverse port is 190-200 at idle, valve body is a upgrade for a triple disc converter.

 

Edited December 19, 2018 by deereman01

[Dynamic]

You'll want to retrace your steps and find your mistake. The Direct clutch, Low/Reverse band and OD Direct clutch are used to give you reverse. Given that you're seeing 200 psi at the L/R servo, I would not suspect the problem to be there, as long as the band is properly adjusted.

[deereman01]

@Dynamic

 

Went back, pulled the pan and valve body, double checked the band adjustment, etc. Used air to check for leaks in the rear servo port, it strokes the band no problem. Front servo and accumulator are billet upgrades. No other funny stuff in transmission on tear down. Everything else looks right. Reverse just isn't there. 
Valve body builder says pressures should be 200 at idle to 280 at WOT. I'm seeing 190 at idle, about 200 at 2000 rpm, and then peaks about 240 at WOT. Wondering if I don't have a cracked housing / leak or something. 

Thoughts?

One more thought, then I'll wait for some info. Truck has a derale pan that looks like a Derale 14210 that I'm finding on the internet. How many quarts does this add to a 48RE? What should total drain and refill capacity be? I'm starting to wonder if something is either way over or way underfull? Rebuild, the Derale pan, new torque converter, it took 18 quarts to get to full line.

 

One webpage for the Derale 14210 pan says a 14010 spacer kit required? What would happen if it wasn't installed? (It was never there?)

[AH64ID]

17 hours ago, deereman01 said:

One more thought, then I'll wait for some info. Truck has a derale pan that looks like a Derale 14210 that I'm finding on the internet. How many quarts does this add to a 48RE? What should total drain and refill capacity be? I'm starting to wonder if something is either way over or way underfull? Rebuild, the Derale pan, new torque converter, it took 18 quarts to get to full line.

 

As far as the trans is concerned the full line is the full line, so if you're not overfilled/underfilled on the dipstick you're fine

 

17 hours ago, deereman01 said:

One webpage for the Derale 14210 pan says a 14010 spacer kit required? What would happen if it wasn't installed? (It was never there?)

 

That probably worth a call/e-mail to derale.