Moves fine in reverse but if I put it in drive it will not take off

RAMITNATION

MEMBER
2001 DODGE RAM
5.9L
V8
4WD
AUTOMATIC
110,000 MILES

My truck is the 1500 model. About 500 miles ago I replaced the transmission and used all synthetic fluids. Then the rear end went out so I went and got one from a junk yard. It was out of a 1996 because it was out of a 1996 the plug for the ABS speed sensor on the hogs head was not the same. So I put a new one in for a 2001 and now the ABS light is on the brake light is on. It moves fine in reverse but if I put it in drive it will not take off. However, if I pull it down into first it will take off with full power then I can shift into second and third. Any suggestions on what it could be? Oh yeah and the speedometer is about 15-20 mph off.

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,643 POSTS

Hello,

It sounds like you have a shaft speed sensor that is not working right. but to be sure lets run the codes to see what comes up.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.

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Saturday, May 1st, 2021 AT 6:18 PM

RAMITNATION

MEMBER
2 POSTS

There is no check engine light.

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Saturday, May 1st, 2021 AT 6:18 PM

KEN L

MASTER CERTIFIED MECHANIC
47,643 POSTS

Is the gear ratio the same as the old differential? The speed being off sounds like the problem can we run the ABS codes to see what comes up. here is a video:

https://youtu.be/rTtAnsOlZU4

Please run down this guide and report back. I would run the engine codes as well even there is not a light on. you can have pending codes which can point us the right direction.

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Saturday, May 1st, 2021 AT 6:18 PM