Help me out with this one please. I have a 81 CJ7 that I have just finished a T-18 conversion on. I rebuilt the T-18 and replaced the First gear and the reverse gear. I have never driven a non syncro first transmission before so I am not sure if what I think is a problem is really a problem or is this how it is supposed to be. When driving and slowing down I can't down shift into second without comming to a complete stop and slightly letting out the clutch. Also when I do start out in first and shift into second there is a grind as it goes into second. I'm hoping that it is happening because first gear is new and also because I have only driven around the block a few times. Anyone else have any quirks with their rebuild and do you think a little more time and distance will help things. Thanks :confused: :mad:

Sounds like bad synchros in 2nd. Did you replace all the synchros? It shouldn't grind going into 2nd.

That is a good question with a messed up answer. I ordered a rebuild kit with syncros and got the wrong syncros. This put my rebuild off a week. I was assured that 2nd syncro would work and that I would have the other 2 overnighted to me. When I started assembling the mainshft I realized that in fact the 2nd gear syncro was also wrong. The old syncros looked as good as the new ones and I couldn't have my jeep down for 3 weeks so I went ahead and assembled it with 2 of the 3 syncros new. But again other than the browning of the old syncros they looked as good as the new ones. All the teeth were sharp and the inside surface still had all the grooves inside and the were fresh looking. I sure as hell hope that I don't have to pull it down just for that one syncro. Thanks.

Why did you need to replace first and reverse, were the the teeth chipped or missing, or were the teeth just rounded over? If rounded over slightly, you may be o.k.. However, if the other situation were the case, then there may have been some significant damage done, which you may chase for ever.

Assuming that everything is o.k., did you replace the sycronizers when you replaced the gears? If not, that is probably contributing to your shifting problem. Keep in mind though, the t18 tranny is a real truck transmission that may be difficult to drop into second from time to time, especially above just rolling speeds. How about end play on the countershaft and on your main shaft, did you check end play? This can also lead to dificult shifting. Lastly, and likely of least importance, what type of oil are you running. If you are running a high viscousity oil, like 140 wieght, that too can cause shifting problems. However, problems associated with oil viscousity normally go away as soon as things warm up.

If the problem continues to occur, I would pull the tranny and check things out.

Good luck,

DL

Jeep, I replaced the first and reverse because they had more rounding than I could clean up with my grinder. I had no problem cleaning up the counter shaft but I felt more comfortable just replacing first and reverse. I am hoping that because first is new that it will free up some with some driving. I now have had a few beers and wont test drive further till tomorrow. As for the end play it was checked and was fine. I am running 90wt. Also I may not have gotten the oil slinging enough to properly lube everything up and it will hopefully ease up a little. So it should down shift on a slow roll into second without grinding most of the time?? Thanks

I feel your pain! I just went through a long ordeal putting a sm420 in my cj5. The outcome, however, was well worth effort.

One last thought on your situation, was the tranny rusted or gummed up on the inside much? If so, I've had problems in the past with rust and/or grap not allowing the gears to slide easily on the main shaft, causing shifting to be very difficult and sometimes getting stuck in gear. This, however, only occurred on transmission that had water damage, and only seemed to affect first and second gear since those gears generally travel the most on the shaft.

Once again, good luck. I suggest having some beers and pondering a bit more.

The trans was sitting on a bench about to be put in a Ford truck when I talked the guy into selling it to me for $100. I got a look inside and other that First and reverse looking a little worn the trans looked great. It had fresh gear lube in it and if I didn't have to replace the main shaft to adapt it to my 300 I would have probably just put it in as it was. Thanks for the input.Iwill go mix something strong and think this over.:D

Here is what I am thinking. Did you prelube the stuff when you put it together? Did you pour some gear lube over the stuff before you put the top on? It will take a little while for the gear lube to get up to the synchros. Best thing you could do to sling the lube around would be put the transfer case in neutral and get in 4th gear for a little while.

mudtruck, I used gear lube on all the parts as they went together, but the syncros may have been a little dry. I used an oil can on all the joints between the gears on the shaft before I buttoned it up. I did not pour gear lube over the gears as the manuals suggested but I did fill the trans from the shift tower hole. I will try to spin the trans with the tcase in neutral for a little while and then take another spin. Thanks

Is the rear output nut tight on the back of the tranny? Ive had mnie come loose on my t98 and 2nd is hard to get into. Check that out before pulling it apart.
Mike

Can't be the output nut as there is a tcase bolted to the tranny and not a yoke. Thanks:D

Thanks for everyones help. I sat in the drive with the tcase in neutral and shifted the tranny thru the gears with the motor running for about 5 mins and then drove it around. Now it shifts smoothly in and out of all gears and downshifts fine too. Seems that it needed a little more lube in the right places. Thanks Again:) :) :)

Good to hear. I will also be driving on my rebuilt T-18 for the first time in a few days and I sure hope everything works.:D