Hi,

I'm currently have a A998 3-speed transmission in my '88 Dakota, but I would love a 4-speed. What is involved replacing the A998 with the A500?

 

what gear ratio in the rear end? If you have a 2.76 or 2.94 youre not gonna be happy with the OD...... those were really common rear end ratios with the 3 speed.

 

I have 2.94 rear end ratio and running 31" tires, so it's terrible. I'm swapping out the rear end ratio to 3.55s, but with a 4-speed I could go even higher.

 

New drive shaft, and some way to shift OD on and off.

The OD can be handled by a pressure switch and a vacuum switch; shucks, you can do it with a manual switch if you so desire. (I'd do all three - manual to force off, and the vacuum to disable on open throttle, the pressure switch to kick it on when you're going fast enough.)

The rear end swap will also take a different speedo drive gear (that's not the transmission, but the rear end due to the change in the transmission.)

You can also pick up the ECU and harness out of a A500 equipped 1988, or out of a 1989, since the 3 speed was dropped either for 1989, or during 1989.

RwP

 

3.55s and a 4 speed trans with OD, won't be any "better" on the top end. it will be a little better starting off from a stop. the 1st 3 gears of the A500 are the same as the "only" 3 gears in the 998

 

Patc has a kit for the od.
https://transmissioncenter.net/shop/...iring-diagram/

 

In case you didn't see my post;

 

Both drive shafts? How much would a A500 transmission w/transfer case cost at the junkyard?

 

If 4WD, then yes; remember, the transmission is longer, so the rear driveshaft is shorter, the front one longer.

Also remember, if it has a transfer case and is 4WD, you'll need to change the FRONT gears also. Unless you're just trying to see how fast you can destroy that transfer case *grins*

I have no idea how much they would be where you are; you may need to ask your folks. Or check at car-part.com and see.

Here ... not that much IMO. However, then it's a used transmission with unknown history; I'd plan to rebuild both if I grabbed from a boneyard.

RwP