New project - 190XT diesel

I picked up a 190XT recently. It was of course in much worse condition than the seller descrided.....jumps out of almost every gear and the high side of the power director doesn't work. It runs really well, but does have a few oil and fuel leaks. I thought about putting the engine in my 190XT gas, but maybe the tractor is worth fixing the rear end. I tried posting a picture but keep getting errors that the file is too large. The grill gas bars with a plastic "one-ninety" badge in the grill.   It also has square fenders with two round light in each side. Any idea what year or series I have?
Thanks

If you are trying to post pictures from your phone do like I do and crop the image. Just taking a little off from the outside makes a big difference. Here's some ways to narrow down the years in a 190.
A. Does it have 2 3/4 inch axles or 3 1/4 inch.
B. Decals.. they used 3 different styles.
1st had the arrow design with allis-chalmers in smaller letters at an angle.
2nd had the arrow design with allis-chalmers in larger letters written normal.
3rd was just the straight long hood decal.
C. Transmission gear pattern. Early models had a gear pattern of 1-2 4-6 3-5 7-8, later was in straight sequence.
D. Sheet metal 64-67 slant fenders,larger side panels and bar grill. 68-71 flat top fenders,2 small side panels on each side and open grill. Of course all parts can be changed over as many have throughout the years. So like Doug said serial number is the only way to pin point it down. Good luck with it,the 190xt diesel is my favorite tractor of all times

You have a series 2,1968. My grandpa bought one new,it was one hell of a tractor. No 4020 or 856 could compete with it.

Thanks for the information.   What should I expect to spend on rebuilding the hi/low and rear end if I do all of the work?