jeep won't stay in 2nd gear

Noticed a small problem with the jeep this weekend. Won't stay in 2nd gear. If I am in 2nd gear, and have the power on, it stays there just fine. But if I let the power up, say, if I take my foot off the gas, it will just slip out of place into neutral. It's not a huge problem, I just have to hold it in 2nd if I am tooling around the 'hood, I just want to know the root cause of the problem.

RE: jeep won

my 1943 willis has that problem Im told it is the Synchroniser.

RE: jeep won

Wear is the root cause. 2nd gear gets a lot of use, tooling around on the back roads, etc. When I was a Kid, I had a 1953 Willis pickup that did that. You can take the lid off the transmission and increase the tension on the detent ball, on the shifting rail by stretching the spring, shiming it, or replacing it. That will work for a while, if the gearbox isn't worn too bad. But your accumulating a lot of wear in there, and it needs to be rebuilt. I can't remember the gearing - if they are straight spur gears, or helical cut gears. The helical gears will have a thrust, one way or the other, depending on if the load is on or off. You might check the lube. Some of those old boxes like straight mineral lube, rather then the "GL" stuff, which would agravate the thrust part on helical gears.

Lee in Alaska

RE: jeep won

Replace the synchronizer.

RE: jeep won

My CJ3B did this too.

Here's a website that explains why...........................
http://www.novak-adapt.com/knowledge/t90_rebuild.htm

Every t90 transmission I had did that.
Back in the mid 70s, I talked to an old army motor vet. He said he was with a unit one time that made a bracket that mounted on the dash board of there M38 jeeps. When you placed the jeep into 2nd gear, and was going to keep in second gear for a while, the bracket would flip over and hold the shift lever. I have never seen this done, but the old guy said it was done on his jeeps.
One of the few, Frank USMC RET

GamaGoat1: Thanks for the information....exactly what I needed.

You bet, glad it helped.

Not sure about yours....

Not sure which transmmission is in my '47 but..... There are 3 little $.50 pieces on the main shaft that will break and allow it to jump out of 2nd when deaccellerating. They were in the kit listed on the aove web site.

Back when I was a young lad of about 14 we rebuilt the transmission and replaced these 3 pieces and it was fine for about6 months then one of the pieces broke and problem came back. Dad decided we needed to fix it so we pulled it out and tore it down only to find one of the 3 pieces broken. Replaced the part and same thing happened about 6 months later. This time Dad said it's not gonna hurt anything so we will live with it. Now that I own the Jeep I am still living with it. Maybe some day I will try to fix it again....

My old man's 58 dj-5 had this problem, we rebuilt the tranny 15 years ago and it's fine.

My 46 2A hasn't had any problems. It shifts MUCH better than dad's jeep, his shifts good, no grinding or anything, but my old jeep has the best shifting transmission I've ever driven.

I have seen that it's a common problem, just not for me I guess. Rebuilding the T-90 is pretty simple.