74 Close Ratio T-18 Shift Effort

Several years ago (with advise from many folks here) I swapped out my original T-14 with a T-18 from another CJ of the same year. OEM spacer, mounts, torque brackets and even the OEM sheet metal transmission cover. Being a close ratio transmission I always use first gear to start off (32" tires with OEM diff gearing). From the outset I noted that there was significantly more resistance in the gear shift shifting from 1st into 2nd than from 2nd to 3rd or 3rd to 4th. Also there was a bit of a rattle in first gear. I have experimented with heavier and lighter gear oil (all conventional) with no change. I'm about 15k miles along now and it seems that the shift effort may be getting progressively more difficult (or maybe I'm just getting old). With all that said I guess what I'm asking is if it is "normal" for the 1st to 2nd shift (with a non-synchro mesh 1st gear) to be a bit more difficult or is it time to pull the lid and look inside. I probably should add ...I don't have any grinding and there is nothing accumulating on my magnetic drain plug... Thanks guys...

 

T18 first gear is made for crawling not getting going.

What gear ratio is your rear end. The 2.41 2nd gear instead of the 3.1 1st is most likely the issue if you are running 3.73s



Gearbox:

Borg Warner T-18

Transmission type:

manual
Number of gears:
4
Gear ratios (overall):
I
4.02 (14.99)
II
2.41 (8.99)
II
1.41 (5.26)
IV
1 (3.73)

Gearbox:
Borg Warner T-14

Transmission type:
manual
Number of gears:
3
Gear ratios (overall):
I
3.1 (11.56)
II
1.612 (6.01)
III
1 (3.73

 

The T-18 used in the CJs through 1976 is a close-ratio variant, with a 4.02:1 first gear. Not a granny gear transmission.

It is not unreasonable to use 1st on the street, especially if you're headed uphill. However, it's meant to be a "supplementary" gear, and shifting from 1st to 2nd isn't going to be as smooth or fast as into the higher gears. The T-18 is not a fast shifter anyway, and I would not try to shift it like a passenger car transmission. The T-14 you had previously has much smaller and lighter gears, and is a comparative breeze to shift. Rowing a T-18 can get tiresome in traffic, especially if you resort to dropping into non-synchro 1st at every opportunity.

What's your axle ratio? IME the T-18 with the 4.27 axles is easy to get started in 2nd. If you have 3.73s, you might be tempted to use 1st on the pavement. I would slip the clutch a bit and start in 2nd, but it's no crime to start in 1st. If I was moving at all, I would start in 2nd. With either of my 3-speeds, I would only resort to 1st from a dead stop.

You should be running the GL-4 StaLube or equivalent in your transmission, not a synthetic or "GL-4 compatible" GL-5 oil. You can buy the StaLube on Amazon, and some stores stock it. When you shift from 1st to 2nd, you are moving a sliding gear to disengage with the cluster (that long throw), then 2nd is a synchromesh gear, with a sliding collar and blocking ring. The effectiveness of the blocking ring depends on the oil. The brass blocking ring is like a clutch, matching the speeds of the meshing gears by friction.

Maybe you need to change your driving style some. I'd suggest you try slipping the clutch a bit and starting off in 2nd. A 258 has a lot of low-speed torque, and you don't have to be moving fast to release the clutch and let the engine lug down to get moving. I'd also suggest using a lighter touch and giving the transmission a little more time to shift. This is not a fast or easy shifting transmission.

If performance is not better with the right oil, there is not much you can do the the transmission with it in the Jeep. You can take the shift top off and inspect it for proper motion. You can move the shift collars by hand to see if there is any excess resistance.

 

A common practice with the IH community is to switch to 50WT non detergent oil to aid in shifting.

Different transmissions come with different length shifters. Longer shifters, such as the ones that come with Ford trucks have longer throws but the shift effort is less. Perhaps going to a longer cane would help. Be aware there are two different tower heights.

Either way, first will always drag due to it being a sliding gear instead of a constant mesh gear.

 

Since second gear is one of the most shifted-into gears it’s common for the second gear blocking ring (synchronizer ring) to get worn. I would change the fluid first and look at the drained fluid and see if there are any yellow particles. If so that is blocking ring material in a T-18. A 4.02-1 T-18 sees a LOT of use of first to second gear. Much more than a 6.32-1 version so second gear synchronizer sees much more wear