stiff gearbox

[lewisgrace]

I am finding that when the truck is cold, bearing in mind I live in England where its cold eleven and three quarter months of the year!, the gearbox is stiff coming out of second, its not a problem selecting second, or any other gear. As soon as the gearbox warms up, 10 or 15 minutes of driving, all seems ok . Its 1952 M37 so is fitted with the non syncro 1st and 2nd transmission. I am new to M37 ownership and would appreciate advice from you experienced lads. I also run a 43 GPW and perhaps I am just used to the driving of that. Any thoughts would be gratefully appreciated .

[T. Highway]

What are you running for gear oil?

Bert

[lewisgrace]

To be honest I dont know! I have owned the truck just five weeks , I topped up with 90 gear oil , although it only needed a tiny amount . Im more than happy to drain and refill with what you experts suggest , thanks Bill

[RMS]

it has been recommended that we run a strait w50 heavy duty engine oil in the transmission
suggested reading:
http://www.g741.org/PHPBB/viewtopic.php ... ion#p39828

[RMS]

more good reads in regards to oil
http://www.g741.org/PHPBB/viewtopic.php ... ion#p39828

its tough to use the search function for oil because what you get is:
"The following words in your search query were ignored because they are too common words: oil.
You must specify at least one word to search for. Each word must consist of at least 3 characters and must not contain more than 14 characters excluding wildcards."

[lewisgrace]

Thanks for all the advice , it certainly looks like 50 weight oil is the one to try , thanks Bill

[PoW]

99% probability the oil is a bit thick.

1% the PTO (if equipped) has too few gaskets, causing it to bind up a bit. Gear backlash was set with a stack of them.

DG

[MSeriesRebuild]

I'd suggest you search on this forum and read some of the woes of the early style trans. A wise decision is to pull the top off the trans and check for lateral movement of the components on the main shaft. Hard shifting is an early symptom of the snap ring breakage issue that is very common in the early trans. Changing oil types is certainly fruitless if that were to be going on. If you are in a cold climate; 40 weight oil may be an even better product than the 50 weight. We do initial fills in our rebuilt components with fluids that are best compatible with the climates they will be going into. Today's gear box oil recommendations suggest either 30, 40, or 50 weight lubricants based on the ambient temps where they will be operating.

The PTO question isn't likely playing a part as far as any binding issues. If that were the case, warming up would not change that, not to mention that the unit would self destruct in a relatively short time. I say that because if backlash is too tight or too loose, out of the ordinary noise will be obvious. As far as that requiring a stack of gaskets, (shims) to properly install. That is not necessarily true. Every unit will absolutely be different. Some require no more than a single gasket to achieve a proper set up while others will require 5 or 6. A too tight set up will produce a whining sound, while a too loose one will produce a clattering or ticking sound at idle. If the gears on the PTO and the countershaft have run for years and have established wear patterns on the teeth; any change of set up will produce some clattering noise, even if backlash readings are within spec.