Mack 9 Speed

[joes mack]

i have a few questions about them 1 are they a good trans 2 what is the shift pattern 3 are they hard to get parts for 4 are they good for off road 5 would one give good high way speed in front of 7.49 rears (50/55) with tall 24.5s 6 what would be a fair price for one that has been siting in a truck for 20 years not moved. any info would be greatly app i know you guys know your stuff about everything mack thanks ..joe

[joes mack]

no info someone has to know something...joe

[phildirt]

The T2090 is a triple countershaft transmission that has been around for a long time. I have one in a RW613 that has gone a million + 400,000 with a couple of rebuilds. It is handling a 500 + hp E9 engine.

I like the way it shifts. I think you could tear it up if you really worked at it.

Adelman's wanted $2,500 for a 1 year guarnteed swap (with a good core)about a year ago.

The LO gear is plenty low and is fine for yard work. My 9th is .71 and will give you close to 100 mph at 2150 rpms.

Price should start at 9 cents a pound - (scrap price)

R 2 4

N

L 3 5

lo - hi button

Skip L on the high side

Phildirt

[David]

Mack has shown two different shift patterns through the years for the 2090. The early one you didn't use L in high range. The later one you don't use 5 in low range. All of ours seem to whine quite loud in 5 low so we use the later pattern. The 9 speed was speced as an on/off road trans. The 10 speed was speced as an on road trans. Revs/mile X final drive ratio will give you RPM's at 60 MPH. 24.5's are 468 rev's/mile. 468 X (.71 X 7.49)= 2489 RPM's @ 60MPH. You might want to look at the T2050, 60, 70, or 80. They are .6 overdrive. Or use the 2090 and add an auxiliary with overdrive. 1200X24 tires will cut your Revs/mile down to 428. Play with the numbers and see what combination fits your needs.

[GreenGiant2]

Mack has shown two different shift patterns through the years for the 2090. The early one you didn't use L in high range. The later one you don't use 5 in low range. All of ours seem to whine quite loud in 5 low so we use the later pattern. The 9 speed was speced as an on/off road trans. The 10 speed was speced as an on road trans. Revs/mile X final drive ratio will give you RPM's at 60 MPH. 24.5's are 468 rev's/mile. 468 X (.71 X 7.49)= 2489 RPM's @ 60MPH. You might want to look at the T2050, 60, 70, or 80. They are .6 overdrive. Or use the 2090 and add an auxiliary with overdrive. 1200X24 tires will cut your Revs/mile down to 428. Play with the numbers and see what combination fits your needs.

Hey

i dont think that the 2080 is the best tranny, i would love to have something different in my 89 dm690, seems like 4th is wound to tight and 5th your luggin on hills, but thats what the salesman said was the best when we bought the truck dont listen to salesmen.

GG2

[joes mack]

thanks from the info it would not be that much dif or no dif from the quad box that was in the truck (7220) in the high gear on the highway. with the 237 i prob wont see the high gear unless im empty. im going to try to talk to the guy agin and start with the scrap weight for the trans i know at a min it will need seals and prob some new gaskets if i can get the trans at a good price. how much do they weigh? . joe

[David]

714 pounds

[joes mack]

thanks that is not all that bad weighs less than i thought . joe

[HK Trucking]

Mack has shown two different shift patterns through the years for the 2090. The early one you didn't use L in high range. The later one you don't use 5 in low range. All of ours seem to whine quite loud in 5 low so we use the later pattern.

Those transmissions suffered from the "range shift self destruction syndrome", so that later shift pattern was designed to allow the range shift to take place at a lower speed, thereby putting less stress on the range shift synchro.

The 9 speed was speced as an on/off road trans. The 10 speed was speced as an on road trans. Revs/mile X final drive ratio will give you RPM's at 60 MPH. 24.5's are 468 rev's/mile. 468 X (.71 X 7.49)= 2489 RPM's @ 60MPH. You might want to look at the T2050, 60, 70, or 80. They are .6 overdrive. Or use the 2090 and add an auxiliary with overdrive. 1200X24 tires will cut your Revs/mile down to 428. Play with the numbers and see what combination fits your needs.

If he's looking for an on/off road transmission, that rules out the 2050 or 2060, as they don't have enough low gear reduction for that.

.

[bts-4120]

with 7.49 gears you will have to use a aux. box to get close to 55mph t-2070 and 6.34 tops out at 55mph thats a .60od alot taller gear than the .71 I like the t-2090 but it's like HK said trouble with the sycro's and they are not cheap

[randyp]

Those transmissions suffered from the "range shift self destruction syndrome", so that later shift pattern was designed to allow the range shift to take place at a lower speed, thereby putting less stress on the range shift synchro.

If he's looking for an on/off road transmission, that rules out the 2050 or 2060, as they don't have enough low gear reduction for that.

.

ah and alas HK, once again you are on the money bout that, I have the distinction of actually destroying a range synchro long long ago in a galaxy far far away, it wasnt pretty,,,keep us straight and informed HK,,,,later,,,randy