1275 Transmission questions

[ichthos]

I know there are four variations for the 1275 transmission, but does anyone have a complete list of parts for the 1275 transmission with cluster gear 22G1100? Also, what parts are typical to wear out? Which are not? Any help is greatly appreciated.
Kevin

 

[Spridget64SC]

Since no one else has taken a stab at this one, I'll give it a go. I'm only aware of two variations of rib-case transmissions for the 1275. The only real internal difference is that the earlier ones had 22G200 series gears and the later had 22G1100 series gears. Some external differences in the very late 1275s due to interlocks on the tower to be in neutral for starting. The main parts that matched up with the 22G1100 layger are; 1/2/R slider = 22G1119, 2nd gear = 22G1120, 3rd gear = 22G1121, Reverse = 22G1114, Input = 22G1117 (very rare) BLMC must have made a million 22G229's and these are the most common input gear, and 3/4 Slider = 22G410 (most likely a Mini crossover). All the other bits and pieces are pretty much shared between the other rib-case boxes. There are plenty of sources out there on the www. for BLMC part numbers for that stuff. The BLMC factory parts book (AKD4501???) is a good source for all factory part numbers and break points.

As for wear out items, the most common is the syncro cones/balk rings. Then the material on the gear itself. That stuff that looks like sintered metal on the balk ring side. Then the little "dog" teeth on the gears. The two slide gears wear on the inside too where they engage the "dog" teeth. Significantly folded back points on these indicate a need for replacement. The outside teeth of 1/R part of the 1/2/R slider will show obvious wear. Laygear gear teeth wear is usually limited to the 1/R teeth (the 13 straight ones). The laygear also wears on the inside bore where the needle bearings roll. Dirty gritty oil will eat this surface up. Same with the needle rollers themselves and the lay shaft. 1/2 & 3/4 shift forks wear on the inside. These forks have pads on the inside and if the wear has gotten past them, then it is time to look for better or new forks. Shift rails wear a little, but usually not enough to matter. The bearings on the main and input shaft wear too. Usually on the inner and outer races. If the center race wiggles too much in the balls, change the bearing. A cheap replacement. Reverse wears where it engages the 1st gear outer teeth. The Teeth that engage the laygear rarely wear.

Some items to look at outside the gear cavity are the rear bush; look at it for wear due to dirty oil or trash getting past the seal. Look at the release bearing arm bush and bolt, these often get overlooks when having clutch engage/release problems. Make sure you have all the shifter anti-rattle and tension parts installed. Nylon cup/spring and the brass plunger and spring. These really make a difference in the crispness of the shift.

Use motor oil of the appropriate weight for your locale and change once a year. I rarely use the gaskets any more, just the right amount of a good RTV/silicone. Make sure to use shims under the tail housing and the front cover to tighten the bearings into the main case.

HTH,
Mike Miller

 

[Billm]

Kevin
Look here for the partslist-
https://www.britishcarforum.com/bcforum/u...list#Post407639
BillM

 

[nomad]

Just wanted to add that making sure the clutch throw-out arm is not loose and locates the carbon throw-out bearing as close to perfectly concentric as possible adds to carbon throw-out bearing life. Least thats been my experience.

Kurt.