Reverse pops out of gear

[LiquidX]

I have been having an issue and brought it up to the attention of Jacks Transmissions who recent rebuilt my tranny. Upon receiving it back I've had the problem of my reverse gear popping out. All other gears are fine and there is no grinding, just a very loud thump when it happens and feathering the clutch is required to help prevent the popping out. I made a video and sent it to them and they stated that my shifter cables are not allowing full engagement due to the excess play at the transmission.

One thing they asked for me to do was to check the brackets and this is where I'm confused.

The brackets holding the cables are all solid and don't allow for full movement. Am I missing something here or am I just looking at the wrong thing as the cables themselves would be the issue?

I haven't had this problem until recently and I have yet to test to see if hand actuating reverse and driving to see if it will still pop out as I'm on stands.


So is there any other way to verify if it's transmission related or a cable problem before I spend $1xx on new cables in hopes it will fix the issue. No one would happen to know of an adjustable set of cables that work for the 2g?

Thanks
Scott

 

[92AWDHX40]

Popping of gear, mm mine did but my trans was shot, when i adjust mine its just in the cabin. I would try that again to see if it helps cables arent cheap.

 

[GsXdSmKingGsX]

Same thing happened to my buddies GSX and he had to replace the cables/linkage

 

[twicks69]

Scott, I am assuming that you are running a 1G head on your 6-bolt setup. You would also be running a 1G thermostat assembly, and a modified lower radiator hose to clear the shift linkage on your transmission. You would also require that the shifter counterweight is chopped off so that it does not hit the lower radiator hose causing shifting issues into reverse.

Confirm that the shift shaft on the transmission is not hitting anything causing engagement issues.

Otherwise, pull the 5th gear cover off and inspect the 5th/Rev hub and slider assembly.

 

[LiquidX]

Tim, I'm still on a 2g top end and nothing has been modified externally on the transmission. Nothing is hitting the weight either. Where might the inspection cover be? Jacks said that this issue wouldn't be an internal problem as they just had the whole thing apart and replaced anything in question.

Victor, only the 1g has the adjustable cables which is something I wish the 2g had.

 

[twicks69]

Well, since you are running a 2G head, the shifter counterweight shouldn't be an issue if you are running a 2G lower radiator hose as long as the intake pipe isn't hitting the shifter counterweight.

I would check the condition of the shifter cables at both the shifter base and the transmission side for excessive axial play; they should not bend alot in any direction so if they bend really easily there is a potential that you have crap shifter cables (new ones should not be causing this issue).

As for the 5th gear cover, it is the transmission end cover that has the 9 short bolts and 2 long bolts (14mm head).

Reverse popout really only has a few causes; the shift cables, the shift counterweight hitting something, loose end shaft nuts (the 36mm nuts that hold the 5th/Rev gearset in place), a missing/damaged reverse wave spring, or a missing/stuck shift detent ball for the 5th/Rev shift rail (14mm poppet plugs/springs/balls on the outside of the transmission case).

 

[LiquidX]

I felt kind of like an idiot. I did manage to find the problem at the cost of a broken part

I checked the 36mm nut under the end case the other night which turned out to be fine. Upon reinstallation, the case cracked on me when the reverse syncro fell out of place a bit. I didn't hear anything odd as I play some loud music but I wasn't happy after seeing it.

JNZ Tuning sent a replacement case out the next day and got it back together last night.

Well after I broke the case I looked up while laying on the cold garage floor and realize the orientation of the massive 4" turbo inlet hole, the lower radiator hose, and the counterweight. When the 4" intake in installed, it pushes the radiator hose into the counterweight only when it's in reverse. So needless to say, I grinded it off and I have reverse...

Edit
...I thought I had reverse. Turns out it still pops out I've checked everything so far and the last thing on the list is going with new shifter cables. If I hold the shifter in reverse and let the clutch out it will still disengage and grind a bit

 

[jawar666]

Did you have luck with the shifter cables?

I have exactly the same symptoms on my GSX...

 

[1991GSXAWD]

Disconnet the cable at the transmission and have a friend manually shift it into reverse, if all is good than you have a cable that is stretched or out of adjustmemt.

 

[LiquidX]

I'm still waiting on the cables to arrive.

I did come to find out that when the gear "pops out", it creates the loud thump but is actually still able to reverse again for a second attempt. Usually on the 3rd reverse attempt (all without touching the shifter) it will fully pop out of gear and into neutral.

 

[LiquidX]

Update

I just installed the brand spanking new OEM cables today with the rubber bushings on the ends and it's still popping out of gear. It doesn't seem to be as bad as it used to be but it's still doing it.

Have to admit though that putting in new cables really buttered up the shifting

So currently I'm just lost as to what is causing it.

 

[twicks69]

Did you disassemble the transmission and inspect the actual reverse gear and make sure that the teeth aren't worn out causing partial engagement/popout? Being a straignt-cut gear with an edge that gets "levered-into" position on a rail and engages the teeth on the 1/2 hub and slider and the input shaft, there is alot of wear over time on these parts.

Cheapest thing to do first would be replace the detent springs under the poppet plugs on the outside of the case -- MD771797 x 3 for all three springs. They should be around $2.00 each.

What was the condition of the reverse wave spring and the reverse cone when you had the 5th gear cover off? Did you inspect the reverse cone to make sure it was actually in good condition and could brake the reverse synchro when under pressure? Was there wear on the reverse wave spring? Did it feel really flimsy?

If so, you could always check/replace the reverse synchro, reverse wave spring, reverse cone and reverse cone hardware:

Reverse Synchro (2G): MD746439
Reverse Cone: MD725928
Reverse Cone Screws: MD736513 x 3 -- use loctite blue when reinstalling these machine screws
Reverse Cone Wave Spring: MD744342

The parts should cost around $40.00.

If you do end up actually disassembling the transmission, the reverse gear part number is MD747890 and is around $40.00 also.

 

[LiquidX]

I took the inspection cover off a bit ago and did inspect what I could see under that cover. The wave spring is new and the gear was un damaged along with the syncro. Unsure of what the reverse cone is however.

I'm going to be awaiting an email from the transmission company to see what else they have to say.

 

[twicks69]

The reverse cone is bolted by three machine screws to the inside of the 5th gear cover.

The reverse gear is held in place by the reverse gear rail inside the transmission bellhousing portion and is actuated by the 3rd/4th shift rail/5th/Rev shift rail interlock on a lever.

Really, the easiest way of finding the problem is doing a teardown to figure out what is going on.

 

[LiquidX]

This is end case #2. I cracked the first one putting it back on and both cases have had this issue. I am doubting that two cones are bad and the wave spring was replaced with the good one.

 

[LiquidX]

Update #2

I was told by the transmission company that the reverse switch is supposed to have a washer to allow proper clearance from the shift rail. Without the clearance the switch puts too much pressure/strain on the rail and throws other tolerances out of spec causing issues. I went to double check and I was missing the said washer. I did take notice to my switch being worn down from the shift rail however.

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I put in the only washer I had around that would fit which was a plastic washer about the thickness of 3 regular washers. It was an attempt to fix the issue which failed as well.

I'll see what they say when I receive an email back later on.