View Full Version : 350 gearbox

11-06-14, 06:13 AM
Hi guys,
I had a problem coming back from Mersea Sunday, coming off roundabouts and left hand corners, gearbox was slipping, ok on straight and right hand corners, so suspected low on oil. Got home and dipped it, VERY hard to see oil on dipstick (Lokar) but was low, so topped up. As I said hard to see properly and now have oil on the floor coming from around gearbox somewhere, suspect I have put too much in. I think best solution is to drain and put new in.
First off, would that be a symptom of low oil? ( slipping off left hand corner) and second, what is the best oil, and how much?
Thanks Tel

11-06-14, 06:29 AM
Lokar sticks are terrible things to read. Have had to resort to a little chalk on there in the past which is not ideal.The oil just becomes invisible on that small section marked area and the spiral section above shows nothing. You need a Dexron oil in there and level should be measured with engine running , hot and in park. Are you running a cooler as temperature can force oil from the breather after a good run. Once you've got the level right give it a good check again as there are a few favourite leak points on a 350.

11-06-14, 06:48 AM
checked it when warm from park down to 1st back to park again, running a cooler, never noticed any leaks before under the truck, but there was a film of oil on the rear bumper, on the outside funnily enough, only noticed it last night, didn't know if this was linked

11-06-14, 08:11 AM
If you run a looser converter heat can play a part in pushing oil out. My mate's '32 was at Mersea and although we have a modified breather set up on the car it still pushed some oil up the tube on the journey home.
Totally dry the boxes with stock converter hold about 10/11 qts depending upon sump but you'll never get it totally dry.

11-06-14, 09:21 AM
ok Steve thanks, recommended oil?

11-06-14, 09:22 AM
Needs to be a Dexron to go with GM spec. We used to put Ford type F in them as it firmed the shift slightly but I currently run B&M fluid in mine.

11-06-14, 03:23 PM
ok thanks Steve

11-06-14, 06:29 PM
Think I have offered some advice on the other channel.

Drain and refill about 4-5 litres. Total dry rebuild as said (depending on the Converter) 9.5 to 11. Some 4x4 can take even more. Need to know the original car it came from. Standard or deep sump?

Check your sump for debris. Only other thing that i can think of that may spin up on a corner going one way is low tyre pressure on one wheel.

12-06-14, 04:03 AM
it was a new box when built the truck, b&m chrome pan, don't think any other changes, thanks for looking