Need some help figuring out why my rear dual case is popping out of gear.  I have 2.28 in front with a 4.7 twin stick in the rear for an 86 4runner.  The issue is the High/low shifter can not stay in low gear when going down hill.  Even if i hold my hand on the shifter, it still pops out of gear so i just keep my foot on the brake.   It's been an issue ever since I built the cases and installed it three years ago but not a big enough issue to worry about. However, it seems to be getting worse. 

I've installed HD springs for all three decent balls (front and rear case), clearance looks good around the shifters, and the stock motor mounts look good.  I've read that a lot of people have issues with the front case popping out when the shift rail isn't trimmed correctly but it doesn't matter position of the front case, it still pops out as I'm going down hill.

Would the shift forks be worn down on the low gear and it can't hold it position? Any help on possible solutions would be greatly appreciated.   

Thanks,

I don't think the boot is pulling on the shifter cause it still pops out when i'm trying to prevent it by holding it with my hand. 

when you had to trim you shifter rails, was your front or rear case popping out of gear?

I have the HD springs in each location.  Before the HD springs were installed, the case would pop out much easier so they helped a little but didn't solve the problem.  What do you mean by the detent pin and balls?

I ended up giving my transfer case to a shop to help determine why my rear case is popping out of gear (high/low) as I'm going down hill.  After he pulled everything, he was not able to see anything out of the ordinary but some play with the high/low shifter fork and clutch sleeve. Meaning side to side movement when engaged with the low gear.  When he compared it to the front 2.28 gears and the fork and sleeve had very little side to side movement when engaged.  That was his only thought after breaking it down.  The 4.7 gears are TG and have been popping out since I put them in however it was reduced when i put in the HD springs.  I was reading that the older Marlin 4.7 gears didn't have a 2 degree taper on the gear and customers complained their cases would pop out of gear. Then Marlin changed gear cutters and incorporated the 2 degree taper. Does anyone know if the TG gear set have the 2 degree taper?

I understand I'm on Marlin's form asking questions about TG products but I'm trying to talk with an many sources as possible to figure what's going on with my set up.   

My other possibility is a worn down shifter fork and clutch sleeve that is causing a good amount of side to side movement.  Has anyone encountered this before or some ideas to confirm if this is my problem?  Also, what about purchasing a new sleeve and fork?  Who provides these as individual part other than the dealership? 

Thanks for the help.   

Need some help to determine if the gear teeth on the 4.7 low speed gear looks normal.  I know my issue is coming from the shift collar not staying in place on the gear but I'm not sure why. I did get new pocket and needle bearings to compare, since they were cheap, but doesn't seem much different to the original.

The mechanic that has my case doesn't like how one side of the teeth appears to have some wear on it compared to the other side.  I talked with Marlins shop and TG and both said it's normal to see some where on these teeth.  Do these look normal?

Looks perfectly normal to me. Is your detent ball and spring in properly?

Yes. Put it together and see if it looks and feels correct would be my only suggestion unfortunately.