What Speedo Gear For 90 5.0 W/ 3.55 Gears

[BNAZ]

I have a 90 LX that currently has optional 3:08 from factory. I'm installing 3:55 gears.
To figure out what new speedo gear I need the chart says I probably have 8 drive gear teeth. Thich means I need a 23 tooth speedo gear. Not available
Did the 90LX come with T5 or T45. Also is it 7 or 8 Drive gear teeth.
Can any one help

 

[04sleeper]

Go here and select which year to help you out.
http://secure.50resto.com/product1.cfm?SID=1&Product_ID=226&Category_ID=145

 

[BNAZ]

Thanks 89Sleeper. It seems like I do have the t5 w/ 8 teeth.
What is difference between T-5 and the T-45.

 

[tjm73]

Thanks 89Sleeper. It seems like I do have the t5 w/ 8 teeth.
What is difference between T-5 and the T-45.

Biggest difference is the T5 has a bolt on bellhousing, while the T45 has an integrele bellhousing.

 

[BNAZ]

The 50Resto site says the Tranmission drive gear must be changed also for correct speedo calibration with the 23 tooth speedo gear. Do you know what else I need to do. Also is it easy to change speedo gear.

Thanks again 89sleeper and tjm73

 

[04sleeper]

The spedo gear is not hard to change at all. There is 1 bolt retaining the cable in the tranny. After you pull the cable out of the tranny you will see the gear. There is a metal clip that pops off with a small screwdriver and the gear comes off and new one goes on. Then pop the metal clip back on with your fingers and bolt it back into the tranny.
If you have to change the transmission drive gear then you will have to remove the tail shaft housing to get to it.
I don't know if you feel comfortable with doing these things or not but if you are ok with it, it is not too bad.

 

[BNAZ]

What would be effect if I only changed the speedo gear and not the trans gear
I suppose I should still change speedo gear. What do you think?
Thanks again 89sleeper

 

[04sleeper]

I might work without the trans gear. Worst case the spedo might bounce up and down a little.

Be sure to check the stamp on the side of your tranny for the year. I have found that sometimes the stamp will say "89" on a 90 year car and need the 89 year gear. Inthat case you would need the 20 tooth gear.

 

[BNAZ]

Thanks again

 

[tjm73]

What size tires are you going to be running?

 

[BNAZ]

I havew the new gears in and like the improvement in acceleration.
I'm surprised at the how high my car revs at. I didnt put the new 23 tooth speedo gear in so the speedo is off. It reads 80 but I'm probably really at 65-70 mph. I'm reving at 2100rpm and I used to be at 1750 doing 70mph.
Does this sound right. Please advise.

 

[04sleeper]

I have the new gears in and like the improvement in acceleration.
I'm surprised at the how high my car revs at. I didnt put the new 23 tooth speedo gear in so the speedo is off. It reads 80 but I'm probably really at 65-70 mph. I'm reving at 2100rpm and I used to be at 1750 doing 70mph.
Does this sound right. Please advise.

Sounds about right.

 

[squeeeg]

Just go to your local jeep dealer and get the 23 tooth gear. It isn't 100% accurate but it is about 99.8% so don't worry about it.

 

[BNAZ]

At this time I have stock tire size. 225/60-15. I have 20K on these, so next year I will probably buy 55 series.

 

[cobradvm]

I have a 1990 GT so the tranny should be the same. I put in 3.73 gears and my speedo was way off. I put in the 23 tooth gear from a Jeep dealer (About $15 or so) and I am pretty close to perfect - with 3.55s you should be just about right on. The tooth pattern is not exact so it may wear out or chew up the teeth. But it is an easy replacement. I just measured today how far I am off - it is exactly 9.9 miles to work, and my stang speedo reads 10.1-10.2 - so I am off about a 1/4 mile per every 10 miles which is 2.5% - close enough for government work!