Hi Guys,

I have heard of a replacement part for the output side of an H55F (Think its an entire gear or shaft or transfer input or something?) that strengthens a weak link in this box. Searched for ages but theres not much info on these boxes. Was told this by someone who races a 70 series.

Apparently another weakness is 5th gear. It doesnt actualy break I think it just starts popping out?

Reason I ask is I am fitting an LS2 motor :D

-Matt

most of the h55f transmissions are in 60 and 70 series rigs that are semi-stock and you really don't run into any problems with them.

you might want to look into running a fdifferent transmission if you're worried about it though.

the NV4500 would be an option. very strong but it shifts like a big truck transmission; cause that's what it is.

another option would be the AX15. i just saw one of these bolted to a late model vortec and it looked like a sano job.



what type of rig are you running? how about some specs?

Hi,

I have a 96 HZJ70 (SWB)
it has a 1hz Diesel with H55F at the mo, which I have turbocharged. Goes ok for a disease-l but i drove it through a deep bog about a year ago and sucked water through the engine and its been running rough ever since.

Its been my dream for about 10 years to own a v8 cruiser,
so ive got myself a good deal on a surplus stock LS2 motor from a Holden dealer in Australia, which im setting up to run on Megasquirt Ecu.
The LS2 should keep the weight down a bit, especially over the 8'' front diff.

NV4500 boxes and the like are hard to find here in New Zealand, whereas H55F's are only a couple hundred bucks. The the h55 box is physically huge and trying to change gears feels like your trying to stuff an engine block into a wood chipper. Just heard it has a couple problems once you start feeding 400hp through them.

I am planning on using a Marks Adaptor bellhousing and clutch kit to install it, unless anyone has a better idea?

Well I found some info on the part,
talking to The 4wd Shop in Australia:

"a modified transcase input gear 32 teeth, in the orig box there is a collar next to this gear on the mainshaft which is not splined. The modified gear has this collar intergrated and is splined therefore you get more gear to spline surface to take the load etc more efficiently"
" its now a common upgrade when rebuilding a box my importer gets them made in Italy and we can sell them to you for
$ 275.00 inc"

Im going to investigate further.

that's the "mcnamara" transfer case input gear. it's commonly used when the splines on the transmission main shaft show severe wear. that way you don't have to replace the shaft. the wear on the splines is usually due the high milage.