Intermittent Transmission Problems

[83NellyBell]

Rundown on the particulars to avoid confusion. 1983 CJ7 AMC 258 i6 / 4.2l I6 T-5 Dana 300 . Ok here's the issue; the shifter will fall out of first gear once I have selected it and clutched off into gear. The Transmission will not slip at all (in any gear) nor has it seemed to fall out of any other gear. The problem just seems to be with first gear, and the problem is mainly from a stop or very slow speeds. If I hold the shifter it will stay. Now it does not exhibit this behavior all of the time. This morning it did it and then later on it was business as usual. The shifter never really felt like it was "in" gear the shifter never showed that crisp almost "click" once she's in gear. I base this off of my '68 Mustang, when you're in gear you know it, there is almost a little detent on shifts as if to prevent you from accidently shifting out of gear. So I had initially tightened the bracket over the shifter selector.

Now my first inclination was that this was the First-Second Gear Shift fork. I'm not sure if it is worn down, or if there is excess play from being low on fluid. But it doesn't present a problem shifting from first to second. I'm nearing the end (I hope fingers crossed) of a restoration and now I'm greeted by little mechanical quirks courtesy of the previous owner's neglect and abuse. Best course of action is isolate the problems as the appear and eliminate them via punchlist to keep from being overwhelmed. But boy I tell ya the adage couldn't be more fitting. J.E.E.P. JUST EMPTY EVERY POCKET

 

[priceg]

On the shift hub there are small springs that apply pressure to the shift dogs. As the shift dog springs age they let the shift dogs move to much in the hub causing the outer hub to engage poorly. If I remember correctly, a T-5 has three dogs per hub. All three have to have a poor engagement for it to pop out of gear.

 

[BusaDave9]

The first gear and its syncro is worn. Your Transmission needs to get rebuilt or replaced. I would not rebuild it.
I had a jeep just like yours (except my was an '82). When my T-5 gave out I put in a T-18 .

 

[83NellyBell]

If the synchro was shot then I'd get grinding. If the gear was shot it wouldn't drive right in first gear. But when it is in first gear it drives fine, and no grinding. It never grinds or slips in any gear. However I think Priceg has a good conclusion and seems reasonable. First though I'm going to drain and replace the fluid because it isn't a question of grinding or friction in the Transmission , nor does it miss shifts.

 

[BusaDave9]

Either way I think the Transmission needs a rebuilt.
Here is a link to someone that had the T-4 in a jeep pop out of 1st gear:
86 cj7 difficult to shift pops out of 1st - JeepForum.com

The T-5 was also used in mustangs:
http://www.mustangv8.com/forum/5-0-mustang-technical-forum/1995-t5-pops-out-of-first-help!/

t-5 popping out of first gear - Mustang Forums at StangNet

Car pops out of 1st gear? - LS1TECH

 

[priceg]

If the synchro was shot then I'd get grinding. If the gear was shot it wouldn't drive right in first gear. But when it is in first gear it drives fine, and no grinding. It never grinds or slips in any gear. However I think Priceg has a good conclusion and seems reasonable. First though I'm going to drain and replace the fluid because it isn't a question of grinding or friction in the Transmission , nor does it miss shifts.

You are correct. When brass rings fail, it drags into gear roughly. When a gear tooth chips or fails you get a knock or nothing at all. T5s are a light duty Transmission , however, parts are fairly cheap and plentiful. I just replaced the T-4 in mine with a T-176 . My cluster gear failed with extreme prejudice.The cluster is the most expensive gear in the Transmission , so I bailed on the repair and went for the upgrade. Hope this helps.

 

[83NellyBell]

Thanks Price, checked the fluid. First off it's low and second it is the wrong kind. There is gear oil in there, but with the T-4 and T-5 's they get filled with Dexron II ATF NOT 80W/90 Gear Oil. Different viscosities will most definitely change the behavior mechanically. But true they don't really pay in my book to rebuild. Good as a light duty Transmission , but when they go it's better to have something more stout. My plan is when the T-5 goes to replace with the NV4500. It works two-fold for my plan. One is it gets me what is arguably one of the best 5 speeds ever and second it is a direct bolt on when I convert engines. When the AMC 258 i6 / 4.2l bites the dust rather than rebuild I'm going 4bt.

 

[hagar]

ATF was to be replaced in T5s per factory bulletins.
8983 000 000 was the replacement lubricant factory part number.
We called it "stink fluid". I was very strong sulfur smell and looked very dirty coming right out of the bottle; very hard to wash off.
When that was phased out, the recommended fluid became 75-90.
The 75 allowed for easier shifting in cold weather.
Nothing wrong with 80-90, but will be hard to shift on very cold mornings.
It will be alomst impossible for you to tell whether 75-90 is in your Transmission now. If it's clean, I would just top off and run that, after all, you may be changing Transmission in the future anyway.