6x4 jumps out of forward gear

[cvtaylor]

My 1999 6x4 jumps out of forward gear under load. If I hold the shift lever down, it will stay in gear till I let go. I have heard the dealer will fix it for a fortune but there may be a kit to install that will fix it. Can anyone help?

[Suffolk Dave]

I had a similar problem in one of my 6x4's and was sure it was going to be the shift collar on the input shaft...there are ball and spring retainers that fit in the input shaft under the shift collar to keep it in forward or reverse position until shifted back to neutral...after opening my transaxle I found the forward drive gear was so worn it was not able to properly allow the shift collar to fully engage...there are 18 internal splines on the shift collar and there were only 9 raised teeth on the forward drive gear so that is why it wore out first... I ordered a new fwd drive gear for the input shaft and when it arrived I was glad to see that JD had figured it out and the new gear has 18 teeth...shifts great now...the reverse drive gear on the input shaft only has 9 teeth but was in great shape so I did not replace it ... the fwd drive gear was $168.00...it takes a bit of work to get the transaxle out but was not hard to repair or get parts for...there is also a shift block that engages the shift lever with the shift collet and if it is too worn and has gotten thin it could cause shifting problems...bottom line is when you open the transaxle it will be easy to see which of the items are worn on the input shaft.
Hope this helps
Suffolk Dave