Thread: Comp G Axle ??

They don't.

Just the GT to GTP have different passenger side axles because of the diff.

FiveFinger.. got a question.. so not having an HD diff will the GTP passenger side axle work on a GT or will I have to switch over to an HD diff ?... OP sorry to thread jack lol

Because the gearing is different from GT to GTP, (3.29's to 2.93) the HD diff makes the axle different.

You would have to swap diffs if you wanted to use a GTP axle, but really there isnt a huge gain from swapping diff/ratio's.

What's different about the axle?

.. and I thought what made the gearing different was the chain not the Diffs.. thought they were the same ratio for the GT and GTP just the later was stronger??

the diffs are also gear ratio specific. and FYI if there is a gear change you will also have to get re-tuned

Ohhh ok well damn i am an idiot lol i thought the only gear ratio change was from the chain.... and i know you have to re-tune for the Chain but i thought you could just drop in the HD diff and Axle?? or am i mistaken.. again lol

Someone can correct me if I am wrong, but the length the axle is different.

And that all GT and GTP transmissions run the same exact chain. The diff will determine the final drive ratio that we refer to as 2.93 or 3.29. Because when you look at any tune, the number in the table is always 2.93 but the final drive ratio number is different.

ahhhh ok now it all makes sense lol.. guess i will be returning the pass axle to Orielys and getting the stock one haha.. no monies for the HD diff upgrade right now lol

thanks for clearing all this up lol

The HD s diffrent not just because of the diff its also the diff cover which is longer which makes the axle shorter than a non hd

Ok guys im going to do a bit of clearing up here.

First of all the difference between the 4t65ehd and 4t65e is ONLY the differential. The differentials are the exact same gear ratio but one is stronger. The stronger HD differential is a bit longer so you need a different differential cover and shorter axle (gtp axle in this case). You do not need to retune when switching differentials. You could even put a non HD differential into a GTP with no other changes other then the differential and axle.

Gm did design different gear ratio differentials for the 4t65e but we did not see any in the grand prixs / wbody cars.... in fact I believe they didn't use anything but the one size in the usa market.

The final drive changes on our cars at least are always done by changing the drive chain. Thats why when tuning these cars you actually don't tune in a gear ratio you enter in your chain / sprocket ratio. For a non supercharged car the ratio is 1.00.

I think the only time we had a stock 3.29 gear ratio was the 97 GT's with the 4t60e trans.

See I could have swore I remembered reading that the Diffs dont determin the final gear ratio..and they are the same ratios for the GT and the GTP.. it's all in the chain for the final drive ratio

I found the info I read a long time ago about the differences between the diffs.. from Thrasher

http://www.thrashercharged.com/tech_htm/FAQ-4t65E.shtm

some 03+ tranny's have a FDR altering diff...previous to that its just the "straight ratio" diffs that do not change FDR
the 04+ ULEV L26 GP's have a diff that turns the 3.29 fdr chain equipped tranny's into a 3.05...the taller gear than a standard 3.29 NA trans is what helped GM get the ULEV certification

throw that diff into a 2.93 chain trans and youll get 2.84 iirc

I know I did the calcs for the 1/2 mile event with the hd/non hd "same ratio" diffs maxing us at 165 in 3rd at 7k where the 3.05 would let us take 3rd gear to 17x at 7k
mostly a pie in the sky math exercise its a viable option since we only have a 3.29 FDR GMR chain...

the 4t80e is the trans with all FDR adjustments via the output/differential planetary gears, yer a 1hr diff swap away from 3.11, 3.48, 3.71 fdr's