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350 chev R380 strength
Posted: Sun Oct 11, 2009 9:26 am
by presto
tried to do a search but its not working for me at the moment..
im putting a 350 chev infront of an R380/LT230 using a marks adaptor kit, just wondering how well the box will handle the torque. from what iv read the 380 refers to how much torque it can handle but the gearbox is an unknown quantity (dunno the history). just curious if there is anything i should be weary of?
cheers
Posted: Sun Oct 11, 2009 11:47 am
by Bush65
The LT designation was applied when Leyland owned Land Rover. LT for Leyland Transmission. The number after LT is the centre distance in mm of the gearbox main and lay shafts (for gearboxes), or between the input and output shafts (for LT230 transfer case).
R380 gearbox was designed after the demise of Leyland and R stands for Rover. 380 is the torque rating of the gearbox in Newton metres.
The R380 was a redesign of the LT77 (which was based on an old Jaguar 4 speed gearbox).
The R380 has undergone a few changes and the suffix letter (right side of box) tells which you have.
From Ashcroft website:
R 380 Development
The R 380 was introduced in 1994 with the suffix J which was a significant improvement on the LT 77 it supercedes, differences included a steel oil pump (as opposed to the LT 77 fibre one), an additional 2 support bearings were used on the layshaft and the mainshaft, wider gears, bigger diameter syncro rings, syncromesh on reverse and a longer mainshaft spline.
This suffix J did unfortunately have a couple of design flaws which gave the R 380 some bad press, they were prone to the mainshaft shearing across the oil feed holes, the layshaft also sheared at a stress concentration behind the sandwich plate causing loss of 5th and reverse also early ones still suffered from mainshaft wear until the cross drilled transfer case gears became fitted as standard on the suffix G transfer cases.
In 1999 the suffix K was used very briefly for a few months then came the suffix L that is used currently. The J and L are very different, 2 of the bearings were substantially uprated and pinion and layshaft teeth were widened again, this results in a much stronger unit.
Posted: Mon Oct 12, 2009 9:39 pm
by presto
thanks heaps for the info, its a 2002 box so i'll have a look at the numbers and find out what one i have. thanks again
Posted: Tue Oct 13, 2009 5:30 pm
by presto
does anyone have suggestions on what manual gearbox would be more suitable for the chevy or is there a way to beef this one up? im a little weary on wasting time fitting this one and spending all that money on the adaptor kit then have it fail on me... i have a built turbo 400 mated to a LT230 which will bolt straight on but i really want to keep it manual.
ideas anyone? pretty please?
Posted: Wed Oct 14, 2009 8:01 am
by nottie
AUTO
Posted: Wed Oct 14, 2009 1:28 pm
by discokid
Presto
I found that an R380 didnt hold behind a mid 4.6lt years ago
My gearbox guy told me that the bearings etc just arent big enough to handle the power and the offroading situations we all tend to put these vehicles in . We rebuilt it twice then got rid of it as we couldnt get it to work.
Is there any particular reason you dont want an auto? A built auto in most situations should last
Ive got a built TF 727 (which toook quite a bit of development) behind my 6lt gen 3 and its been fine so far.
Posted: Wed Oct 14, 2009 5:06 pm
by presto
discokid wrote:
Is there any particular reason you dont want an auto?
its just more fun to drive and i perfer it far more offroad. dont mind an auto when driving to and fro but for the purpose im building this car for, a manual would be much more preferable. has anyone tried anything exotic to make a stronger manual fit the RR?
Posted: Wed Oct 14, 2009 8:06 pm
by garrycol
Posted: Wed Oct 14, 2009 8:15 pm
by presto
cheers mate, iv been all over that site about a hundred times in the last couple of years (cant get enough of the twin turbo set up) but he doesnt have any info on adapting manual boxes to it. which sucks, i think its a good indication that putting the auto in is the way to go.