Engine/Transmission (1998.5 - 2002) 47RE 2nd Gear TC lockup?

[Dkuhlman]

I've been looking here and elsewhere and have conflicting info so far. Does the 47RE in my '02 lock the torque converter if I put the lever in 2nd? And if so, does anyone know at what speed?



The reason I ask is I recently bought a toy hauler trailer and would like to ease it up and down the really steep hills when in the mountains.



Thanks,



Don

 

[paulb]

I've been looking here and elsewhere and have conflicting info so far. Does the 47RE in my '02 lock the torque converter if I put the lever in 2nd? And if so, does anyone know at what speed?



The reason I ask is I recently bought a toy hauler trailer and would like to ease it up and down the really steep hills when in the mountains.



Thanks,



Don

My trans did not lock in 2nd when it was stock. With my DTT trans it will lock as soon as it shifts to 2nd. Only tried that once, scared me! :-laf It will lock whenever I throw the switch in 2nd thru 4th. I suspect it's because of mod's that DTT does to the valve body.



Paul

 

[Hahn007]

Don,



In stock configuration your 47RE will not lock up in second gear. In fact with the stock TC and valve body you don't want it to. The TC only locks in third and OD and only as long as the throttle is above idle. As soon as you lift your foot from the throttle the TC will unlock. This is done intentionally to protect the stock TC.



Some people will "rig" a switch to manually control the locking/unlocking of the TC. The problem with this method is if line pressure is not increased your TC lockup clutch will begin to slip. Once this begins to happen your TC is pretty much headed south.



I learned this the hard way by adding an Edge EZ with a stock transmission and TC. It worked for a while but after towing a few loads the TC started to slip. Once it started I was unable to accelerate in OD without the slippage while running empty.



If you want TC lockup to improve engine braking I would highly recommend an aftermarket valve body to safely increase line pressure and a TC lockup controller. There are several aftermarket transmission companies you could consult. ATS, DTT, Goerend Bros. are just a few of the popular choices on this board. I called several of them while deciding which trans to choose and they were all very helpful and seemed quite knowledgable.



Good luck with what ever you decide to do.



Chris

 

[SnoKing]

I've been looking here and elsewhere and have conflicting info so far. Does the 47RE in my '02 lock the torque converter if I put the lever in 2nd? And if so, does anyone know at what speed?



The reason I ask is I recently bought a toy hauler trailer and would like to ease it up and down the really steep hills when in the mountains.



Thanks,



Don

I just completed my first trip into the mountains after installing a complete DTT upgrade 11 months ago. I have a DTT complete rebuild with billet input and 2nd gear cage, DTT smart controller, 89% TC and Banks 4" Exhaust Brake. We went over the North Cascade Hiway in the Northern part of Washington and spent a week in Eastern Washington. We are towing a 5th Wheel that weights 11,250 lbs and truck is 7K ready to pull. On the east side of the North Cascade pass I shifted into second gear at the top (DTT puts a switch on the linkage to lockup in second and valve body mods) and went down the East side without touching the brake peddle. After decending the steepest part, I shift into 3rd and back on the exhaust brake and went down the rest of the way touching the brakes only once at a sharp corner near the bottom of the pass.



My wife did not understand all the money I spent last year, but I have to tell you I love the setup. From Ellensburg to Yakima is a pretty good hill, ran down both sides at 61 mph in OD on the exhaust brake and never touched the brakes. I have the 4:10 gears that are better for towing with the auto, DD1 Jammers, and Edge Comp without the pump tapped, love the towing power. I only have to watch EGT's in 3rd when at high RPM's. I am still running the HY35 turbo, so I have not tapped the pump wire.



The lock to lock shifting with the smart controller on takes a bit to get use to. I have power for the smart controller and Banks brake on a old style head light switch on the floor, so I can operate it with my left foot. I have a second switch to disable the exhaust brake also. Brake is connect to APPS in standard Banks configuration and works even with cruise control.



So spend the money if you want to be safe. transmission with billets, Exhaust Brake/down pipe, DD1 Jammers, Comp, Smart Controller, 3rd gen track bar equaled 8k. My transmission only had 34K on it when I did all of this, but to pull good and have a reliable exhaust brake setup, you have to build the transmission to handle it. Some people take short cuts, but I did not want to pay to go into the transmission but once.



The only thing that I am now thinking about is to maybe activate the brake lights when the exhaust brake is on, as I hardly ever touch the brake peddle.



SNOKING

 

[klaybus]

DTT & the brake

Excellent post Snoking! I wish I would have had the extra coin to go the Billet route when I had mone done... When I have mine gone through again the Billets will be done & the controller installed before I leave Bills shop. Your post reflects the exact reasons I want to get mine done. Theres nothing more un-nerving than going down a winding pass with an auto & having to depend on the service brakes only...



Clay

 

[Dkuhlman]

Thanks guys, you've confirmed what I was afraid of. I know the auto transmission is the weak link and that's one reason why I have avoided bombing for now. I also notice the truck works too hard when towing a big load and having to accelerate up a good grade from a dead stop. Here again, if I could get 2nd gear lock up, I could use some of that torque rather than listen to the revs scream while the TC slips along until I can get 3rd engaged.



Snoking, I've admired your set up for a while now. I'd like to do something similar but maybe with the new Edge Juice if they get it out for our trucks. I also agree the 4:10s are much better for towing but man does this thing roll when empty! I was thinking of an underdrive to split 3rd and 4th but will wait until I can get the transmission beefed up and some bombing done first. It may be enough.



Thanks again everyone,



Don

 

[Mabrown]

After reading this should I be downshifting to second when pulling the 5ver up a steep grade to keep the rpm's up about 2500 or keep it in 3rd and rpm's dropping to 1800? Would I be causing damaging heat by pulling hard in 2nd since tc is unlocked? I thought it was better than running at lower rpm's but...

 

[klaybus]

If you can maintain lockup while climbing hills leave it in 3rd direct. Of course this is if you can keep EGTs in check. What gears are you running?



Clay

 

[Mabrown]

3. 54 gears and no guages. Are you saying that as long as egt is good then the lower rpm is not "lugging"?

 

[Dkuhlman]

I make a point to not let the rpms fall under 1500 with much of a load. In some of the mountainous situations with 8500 lbs of trailer back there, I have to go for 2nd gear. 1800 rpm would be even better but I don't have the power to pull 3rd with TC locked, up some of the steepest grades.



From the latest posts, it would appear that while you can get a VB and controller for 2nd gear TC lock, it's not recommended without other mods such as a billet output shaft.



For now, when I do have to go for 2nd, I don't run a heavy throttle so that I'm not working the TC hard and causing excessive heat. Ease on up the hill if you would.



Don

 

[azpete]

The 47re when the selector is put in second gear will still upshift to third when the rpm's reach the computers shift point. The Smart Controller has a micro switch that the shift linkage engages when put into 2nd to hold that gear.