best gear box for c20xe

[Mboasty]

ive got an f20 fitted at the moment, which needs replacing, aparently some people run a f18 on these engines, whats best & what do most people prefer.

[Adam*D]

Think an F16 when at 70mph is around 4000 rpm so is quite loud and won't do your fuel economy any good!
F20 is the box of choice I would say:)

[mikey14sr]

Wouldn't go for an F18, they have seemingly soft diff bearings, plenty of them have exploded even on ecotech vectra's (standard ones at that too).

[Philsutton]

F18s came on 1.7TD as well, the vectra ones will be hydraulic clutch so its irrelevant anyway. Oh an also they do WR and CR of most of the box's so saying F18, F20 ect.... has no relevance to ratio.

For example the F18 on the diesel will have WR as thats the nature of a diesel engine, but I doubt the ecowreck one will be.

[craig green]

F20's are pretty much all close ratio arent they?

I'd just source another F20 IMO, jsut find a good one (if poss)

[Stuart]

whats wrong with the current box?

[Will F]

F20's are pretty much all close ratio arent they?

I'd just source another F20 IMO, jsut find a good one (if poss)

All F20s are CR I believe, best out of the bunch too imo.

F18s are poop and F16s are from an older generation and ratios are pretty similar anyway... F20 all day for me.

[Philsutton]

Am I right in thinking though that the 4x4 F20's are a different FD than the average one?

[craig green]

Quite likely Phil, infact I would bet they vary from Astras to Calibras for some reason maybe.

The F16 CR has a a higher final drive than an F20, so will accelerat a tad quicker as we all know. I'd still rather have an F20 tbh.

[Will F]

Yep, the F20's FD and mid-ratios can be slightly different. I stripped an Astra GTE box, and tried to fit the internals of an XE Cav Sri... Totally different! lol

[Mboasty]

whats wrong with the current box?

rattley! some kind of bearing gone posibly diff bearing noisy when you lift of the acelarator.

[Stuart]

could change the bearings.... ok its a little more effort than simply swapping the box, but atleast you know its got good bearings and not some set of lashed up 2nd hand ones

[Mboasty]

thought about doing that, as found new bearing kits for them, but no tec, how'2, torque settings etc so i decided against. to get my gearbox rebuild would cost around £500 quid, so ive decided to just try & get a second hand gearbox.

[General Baxter]

adam have a F16 4 speed :p

[Stuart]

there arent any torque settings needed (its all clips)
the haynes gearbox manual should have a diagram of the box.

plus its not that hard once you get it infront of you to strip down and rebuild :)

[Mboasty]

oh right i thought the bearings would need torqing up some how? might re consider that option then. it was haynes that put me of doing it as they mention words like "close tolerences" etc! basicly leave it to the profesionals!

[Stuart]

yeah that put me off for a while... Then helped CP strip his F13 Quaife cluster down and soon realised its a piece of piss and there is fook all to re shm/tollerance provided you note where everything went

[Mboasty]

so i wouldent need to wory about re/shimig or toloerance when changing bearings?

[mikey14sr]

The pre-load on the diff bearings is pretty much all you've got to worry about.