# Gearbox Main- & Input Shaft Endfloat **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** mg\ **Created:** [July 3, 2025, 2:17pm UTC](https://community.cartalk.com/t/gearbox-main-input-shaft-endfloat/200870 "2025-07-03T14:17:07Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![der\_wolf\_194040](https://avatars.discourse-cdn.com/v4/letter/d/bc8723/32.png) [@der\_wolf\_194040](https://community.cartalk.com/u/der_wolf_194040)\ **Post date:** [July 3, 2025, 2:17pm UTC](https://community.cartalk.com/t/gearbox-main-input-shaft-endfloat/200870/1 "2025-07-03T14:17:07Z")
Hello, new to this forum with a general question on gearbox endfloat - maybe someone here has the knowledge to help me. I am rebuilding the (manual) gearbox (all helical gears except for 1st/reverse) for my 1964 MG Midget Mk2, I have done this several times in the past without errors. Since the last about 2 months ago however I get intermittent gear noise in 3rd and 4th gear, which suggest that incorrect endfloat is the issue due to mainshaft moving axially and/or sideways inside the box. There is NO SPEC in shop manuals, maintenance or workshop manuals of MG or BMC back in the day that would have suggested best-practice end float figures. My questions is: Is there something as such as a corridor end float safe spec to fall back to, if you don´t have any manufacture-given specs? Thank you. Cheers, Wolf ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [July 3, 2025, 2:26pm UTC](https://community.cartalk.com/t/gearbox-main-input-shaft-endfloat/200870/2 "2025-07-03T14:26:44Z")
Have you asked on MG forums? Someone there may know. ---
**Author:** ![der\_wolf\_194040](https://avatars.discourse-cdn.com/v4/letter/d/bc8723/32.png) [@der\_wolf\_194040](https://community.cartalk.com/u/der_wolf_194040)\ **Post date:** [July 3, 2025, 2:34pm UTC](https://community.cartalk.com/t/gearbox-main-input-shaft-endfloat/200870/3 "2025-07-03T14:34:39Z")
Yes I already did. There are no known figures within the community, so I thought I´d ask here to may get answers from pro-rebuilders or servicemen. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [July 3, 2025, 3:00pm UTC](https://community.cartalk.com/t/gearbox-main-input-shaft-endfloat/200870/4 "2025-07-03T15:00:12Z")
Wow, I thought there would be some MG folk in Great Britain that would know. Maybe call Moss Motors, see if they have someone to recommend. ---
**Author:** ![davesmopar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/davesmopar/32/41750_2.png) [@davesmopar](https://community.cartalk.com/u/davesmopar)\ **Post date:** [July 3, 2025, 3:24pm UTC](https://community.cartalk.com/t/gearbox-main-input-shaft-endfloat/200870/5 "2025-07-03T15:24:33Z")
I am guessing due to your wording, you are across the pond from us here in the mainly USA based forum?? I am assuming by end float and input shaft moving axially that you are referring to the thrust or endplay of the shaft?? If so, then if I was in your shoes, I would check as many manual transmission manuals as I could anywhere close to yours for the specs and take an average and go from there, might be a little trial and error, but it should be close, hopefully there is not much of a difference back then on small gearboxes… Other than MG forums or service manuals, you might look for a core, may not even need to be a rebuildable core, and tear it down for some measurements… ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [July 3, 2025, 3:55pm UTC](https://community.cartalk.com/t/gearbox-main-input-shaft-endfloat/200870/6 "2025-07-03T15:55:28Z")
In the absence of any real spec, I’d be setting endfloat to make sure no adjacent gears clash. Inspect 3rd and 4th for witness marks on the gear teeth to make sure your diagnosis is correct and then look for the proper location to shim the shaft. Given the car’s age, you might have to make your own shims! ---
**Author:** ![weekend-warrior](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/weekend-warrior/32/26122_2.png) [@weekend-warrior](https://community.cartalk.com/u/weekend-warrior)\ **Post date:** [July 3, 2025, 9:11pm UTC](https://community.cartalk.com/t/gearbox-main-input-shaft-endfloat/200870/7 "2025-07-03T21:11:50Z")
> [@der\_wolf\_194040](#): > > I am rebuilding the (manual) gearbox (all helical gears except for 1st/reverse) for my 1964 MG Midget Mk2, I found this forum that might have some info for you. look at 2nd post reply [Gearbox Rebuild - Problem still persists - need Input : MG Midget Forum : The MG Experience](https://www.mgexp.com/forum/mg-midget-forum.3/gearbox-rebuild-problem-still-persists.4944769/) ---
**Author:** ![der\_wolf\_194040](https://avatars.discourse-cdn.com/v4/letter/d/bc8723/32.png) [@der\_wolf\_194040](https://community.cartalk.com/u/der_wolf_194040)\ **Post date:** [July 8, 2025, 12:35pm UTC](https://community.cartalk.com/t/gearbox-main-input-shaft-endfloat/200870/8 "2025-07-08T12:35:10Z")
Hello, thanks for that, but that was a post from me and someone answered it with Chatgpt info (which isn´t correct, as there is no written spec). I am still looking for reliable info, that I can apply on 4speed/3syncho helical gearbox. Cheers, Wolf ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [July 8, 2025, 2:46pm UTC](https://community.cartalk.com/t/gearbox-main-input-shaft-endfloat/200870/9 "2025-07-08T14:46:50Z")
was the pilot bearing replaced? ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [July 8, 2025, 3:19pm UTC](https://community.cartalk.com/t/gearbox-main-input-shaft-endfloat/200870/10 "2025-07-08T15:19:57Z")
Can you find that specification for other manual transmissions? If you can, use what seems reasonable. They all work in a similar way.