Is there a different 5th gear I can swap out for my manual 5 speed?

[phillie]

I'd like to lower my 5th gear rpm. At 65 mph my RPM's are at 2500. I'd like to be closer to 2000.
I've done this in my Honda but I'm not sure if there is a gear that can be replaced in the Ram.
Does anyone know? TIA.

1983 Ram 50 4d55 turbo diesel.

[pennyman1]

Not in the tranny, but there are 3.55 gears for the rear axle, but that would change the whole response of the truck. The other alternative would be a gear vendor overdrive you could switch in and out.

[phillie]

Not in the tranny, but there are 3.55 gears for the rear axle, but that would change the whole response of the truck. The other alternative would be a gear vendor overdrive you could switch in and out.

I don't want to change out the rear axle gears. I rather drop the tranny and change the gear.

I just noticed my mph is 5 miles faster then clocked on gps and speed sign readers. I'm pretty sure the tires are the right size but I'm thinking of going with a taller tires. That may help out.

[camoit]

If you take it to a speedo shop they can add on a set of gears to correct the speed. It goes on the speedo cable.
We have a place in Sac called Commercial speedometer. 916-371-5873. If you call them they might be able to mail you the gear set.
Changing the tire size will kill your power and MPG.

[geezer101]

The speedometers are not super accurate and are generally a bit on the optimistic side when it comes to highway cruising speeds. It would be 'preferable' to change the rear ratios rather than messing with transmission gear sets (there might be an alternative transmission from a Montero with different gearing? Don't know if it's an option or how much work you're getting yourself lined up for in the process...)

[pennyman1]

or go with the tranny from a Mazda rx-7 and the bell housing from the 87-88 Mazda B2600 truck. The 2600 motor in those year Mazdas were 2.6 mitsus. Bill Hincher on Projectzero.org has the bell housing that will work also

[phillie]

My main goal is to drop the highway speed rpms. I mentioned in my first post at 65 mph I'm at 2500 rpms.
I used my gps to check the speed and I'm actually 5 mph slower. So at 60 mph Im at 2500 rpms.
That is way to high for my liking. If I'm hauling a load that could be understandable but my truck isn't really a work horse.
Its mostly for commuting. I may try a bigger tire first. It'll almost be the same as changing the axle ring gear.
Like I mentioned earlier I prefer to change the OD gear in the trans but I have to find the gear first.

[phillie]

or go with the tranny from a Mazda rx-7 and the bell housing from the 87-88 Mazda B2600 truck. The 2600 motor in those year Mazdas were 2.6 mitsus. Bill Hincher on Projectzero.org has the bell housing that will work also

I replied before I saw your post. How much do you think it cost to gather all the parts?

[pennyman1]

not sure - the bell housing is the expensive part. the tranny even uses the same clutch disc as our trucks, so you don't need to change it out. you might even be able to find a rx-8 tranny that is a 6 speed, but I don't know if it has a removable bell housing

[geezer101]

not sure - the bell housing is the expensive part. the tranny even uses the same clutch disc as our trucks, so you don't need to change it out. you might even be able to find a rx-8 tranny that is a 6 speed, but I don't know if it has a removable bell housing

Yes, they are but the bell housing looks pretty deep. It might make 'getting everything to line up' a bit of a challenge.

[camoit]

2500 RPM is only mid power range. The engine only makes 97 HP so it takes RPM to make it go. 2000 and under at freeway speed is bogging it. Go with the larger tires, but be ready to discover the problem everyone else does. Lack of power. Everyone on here that has gone to a larger tire will then complain about the power loss, fallowed by a ring and pinion.