4.10 to 3.55 Power loss?
- Thread starter Tristan
- Start date
Pipeliner_86
IDI up high
I did exactly what you're planning to do. I bought a donor truck that had 3.55's in the axle's, to replace my 4.10's. I did a complete axle swap and built a reverse shackle system in the front while I was at it. I have 35" A/T's and a C-6 also. You will notice a loss of power from a dead start, until you get the truck rolling. With 4.10's my truck could leave little black marks on the pavement now and then. With 3.55's, not gonna happen. The drop in hwy RPM's is well worth the swap. Your motor should spin about 300-450 rpms less than before. If your truck is turbo'd, it should not be a problem, mine is still naturally aspirated.
I say go for it!
I say go for it!
I think it will be a big improvement with a C-6. I swaped my 4.10's for 3.55's and did notice that its a good bit slower off the line. With the 4.10's I'd accidently spinn up the rear tires off the line if in a hurry, can't do it on purpose with the 3.55's. Of course the more relaxed highway crusing is well worth the trade-off for me.
TLBREWER
Windy B Ranch
I've been doing this same comparison over the last few weeks. I have two '91's. Both NA, SC, 4X4, 5spd. I live at 6000'.
Wife's truck has what I estimate to be the stronger engine. However, she has 285/75/16 tires and 3.55 gears. Plenty peppy off the line, but no tire smoker (yet). At 2800 RPM she's doing, well, let's just say she likes to bounce the speedometer needle off the travel stop. The problem is, when going through the mountains, if she gets out of the powerband, she's done. Time to downshift. On the flatland, EGT stays at 6-800 degrees. Through the mountains, it's knocking on 1150's door the whole time.
On the other hand. My daughter's truck has 4.10's and stock size tires. Spin the tires almost at will. Have to go thru the gears faster (of course). At 75mph she's turning 25-2600 RPM. Hills are no problem. Going through the mountains is a piece of cake...the only problem sometimes is keeping up with traffic (i.e. top speed).
Tom
Wife's truck has what I estimate to be the stronger engine. However, she has 285/75/16 tires and 3.55 gears. Plenty peppy off the line, but no tire smoker (yet). At 2800 RPM she's doing, well, let's just say she likes to bounce the speedometer needle off the travel stop. The problem is, when going through the mountains, if she gets out of the powerband, she's done. Time to downshift. On the flatland, EGT stays at 6-800 degrees. Through the mountains, it's knocking on 1150's door the whole time.
On the other hand. My daughter's truck has 4.10's and stock size tires. Spin the tires almost at will. Have to go thru the gears faster (of course). At 75mph she's turning 25-2600 RPM. Hills are no problem. Going through the mountains is a piece of cake...the only problem sometimes is keeping up with traffic (i.e. top speed).
Tom
Diesel JD
Full Access Member
The 4.10s would be OK with a ZF-5 or especially with a US Gear or GV, but witha C6 or T19......you simply can't keep up with traffic without bouncing off the governor all teh time. DOesn't seem good for teh engine even though its said they will tolerate it, and there is supporting anecdotal proof, but there is more proof that even driving like a sane person fuel milkeage with 4.10s and a C6 SUCKS.
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