My 1988 Dakota 2wd needs a new rear end.

18619 Views 54 Replies 5 Participants Last post by RalphP, Jul 2, 2016

dakotakeith

Discussion Starter · May 7, 2016

I'm Keith and I own a beautiful(to me) 1988 Dodge Dakota 3.9l 2wd truck that I happen to LOVE. I bought it from a Farmer about two years ago and one trip into Jiffy Lube and the rear end was squealing like crazy. It ended up being my differential bearings. I bought the bearings, but I've been discouraged from taking this task on myself. I can pretty much do anything I learn on Youtube, but I want this truck buried with me, which means I need this job to last. I've been told that it would be easier just to switch out the entire rear end for a different one. My question is, since this rebuild is probably beyond my ability, and the 7 1/4 angular pumpkin diff that's on it seems impossible to find in a salvage yard around these parts, what other rear ends are compatible with my truck that I could get from the salvage yard and get her back on the road? Let's call this a "work truck" restoration. My everyday truck is a 2004 Tacoma Prerunner, but I want this Dodge to live. Any suggestions? Sorry, I'm typing this at work, so pictures yet. I'll add some later. She's ugly, but she's mine.

Thanks for any and all suggestions.

1 - 20 of 55 Posts

RalphP

· #2 · May 7, 2016

1987-1990 Dakota 2WD rear ends bolt right in.

1991-1996 will work, but you'll need to swap the axles and brakes over.

Also, I'd upgrade to a 8.25" rear end while doing (you SURE that's a 7.25" rear end on it?)

To help, here's a quick chart that lets you visually ID the rear ends Chrysler's used through the years:

RwP

See less See more

hskrRT

· #3 · May 7, 2016

I would pay for the rebuild long before I just slap in a junkyard differential. You could end up with words problems than ou started with. Shouldn't be too bad for a quick rebuild on an open diff.

RalphP

· #4 · May 7, 2016 (Edited)

One other consideration for DakotaKeith is that if he picks up a rear end out of the boneyard, he can pick a 8.25; might could find one with a SureGrip unit; and maybe better gearing.

I'd then rebuild THAT one *grins* That way, the truck isn't down all that long while it's being redone.

But the choice will be not only availability but also on his personal preference and ranking of ease / speed / upgrade possibilities / etc.

To DakotaKeith - if you DO pick up a different rear end, check and get the speedometer drive gear out of the transmission also; unless it's the exact same ratio as your current one. I'm finding the Chrysler drive gears to be like $30 or more on line; the local shop up the street from me (PATC) gets about $39 for a gear. A lot pricier just because I forgot to grab one at the boneyard.

RwP

See less See more

dakotakeith

Discussion Starter · #5 · May 7, 2016 (Edited)

RalphP said:
1987-1990 Dakota 2WD rear ends bolt right in.

1991-1996 will work, but you'll need to swap the axles and brakes over.

Also, I'd upgrade to a 8.25" rear end while doing (you SURE that's a 7.25" rear end on it?)

To help, here's a quick chart that lets you visually ID the rear ends Chrysler's used through the years:

RwP

That 7 1/4 is definitely mine. I didn't mind the drive before, but if the 8.25 is an improvement somehow, I'll seek that one out. I want a smooth drive. It won't haul anything heavy, I'd just like to get it to cruise on the expressway. Suggestions? Also, I've never swapped out a rear end before. Is there a "how to" somewhere on here, or will my venture at the boneyard be my only practice?

RalphP

· #6 · May 7, 2016

The 8.25 is just beefier; some folks buy trucks to haul stuff in, and the 8.25 can take a bit more guff before it decides to become a pile of parts.

It's not a problem with the torque from the 3.9 *grins*, nor with the duty you say you'll be doing with it. The 7.25 is also good'nuff for some folks.

Does your 88 have the 3 speed or the 4 speed auto, or does it have the 5 speed manual?

RwP

dakotakeith

Discussion Starter · #7 · May 7, 2016

RalphP said:
The 8.25 is just beefier; some folks buy trucks to haul stuff in, and the 8.25 can take a bit more guff before it decides to become a pile of parts.

It's not a problem with the torque from the 3.9 *grins*, nor with the duty you say you'll be doing with it. The 7.25 is also good'nuff for some folks.

Does your 88 have the 3 speed or the 4 speed auto, or does it have the 5 speed manual?

RwP

4 speed auto.

dakotakeith

Discussion Starter · #8 · May 7, 2016

Here's some pictures of the diff. Now that I look back at it, it doesn't look exactly like any of the Dodge diffs. The trucks a bit of a "frankenstein". Can anyone tell from the photos if it's the 7.25?

See less See more

4

RalphP

· #9 · May 7, 2016

Looks like my 8.25 - but an easy way is to take a cloth tape measure,wrap it around the ring gear, measure the circumference, and then divide that by 3.14 . Should be about 7.25 or 8.25 inches.

And I bet you'll measure a bit over 25" that way.

BTW - did the mechanic mention which diff bearings are wearing?

RwP

dakotakeith

Discussion Starter · #10 · May 10, 2016

I took my last post down and decided instead to do more research. I measured halfway around the ring gear and it came to about 12.5 inches, which is why I thought I had the 8.25 differential, that is, until I found a write up on another forum and found my identical rear end on a different truck. It is, in fact, the 7.25". I think I may have measured beyond half way around the ring gear, accounting for the 25" estimation. I've decided to disassemble it on my workbench and replace the pinion and axle bearings. Attached is a pic of the Motive Gear part #R7 .25r Bearing Kit W/Bearing Incl. F/R Pinion-Carrier-Pilot Bearings/Pinion Gear And Nut/Gear Marking Compound/Crush Sleeve/Brush/Loctite/Gasket-Rtv.

I've seen some very good Youtube videos and I've learned a lot, so my confidence is up. I plan to remove the rear end, install the bearings, replace the brake lines, replace the rear u-joint, treat the surface rust and repaint it. My only concern is reseating bearings without the proper tools, but I'm confident I can either build a jig or use my vice and a large socket to accomplish this.

If there's something that I'm not considering, please make me aware of it. I'm looking forward to learning more about this truck as I restore it.

See less See more

RalphP

· #11 · May 10, 2016

That's a universal kit, I think - fits more than one rear end.

As long as the gasket matches, it SHOULD be fine.

I'd grab a good rear end rebuild book (I own this one from Amazon: https://smile.amazon.com/gp/product/B00BKRVQUA ) and study it very well before you tackle it.

Since I've not done one (again, I read that book and decided that it was easier to pay someone else instead *grins* but that was my choice), I can't help much past that with actual hands-on.

RwP

dakotakeith

Discussion Starter · #12 · May 14, 2016

RalphP said:
That's a universal kit, I think - fits more than one rear end.

As long as the gasket matches, it SHOULD be fine.

I'd grab a good rear end rebuild book (I own this one from Amazon: https://smile.amazon.com/gp/product/B00BKRVQUA ) and study it very well before you tackle it.

Since I've not done one (again, I read that book and decided that it was easier to pay someone else instead *grins* but that was my choice), I can't help much past that with actual hands-on.

RwP

I couldn't even find a book on rebuilding 7.25" rear diffs, so I've decided to leave this up to the Pros. I'm going to see what it will cost to have it rebuilt and in the meantime, I'll continue to search for a salvage yard replacement. I'm in no hurry.

RalphP

· #13 · May 15, 2016

Well, just as a note, that book I linked to includes the 7.25" diff (front/rear doesn't matter for most of the instructions).

But yah, I've made the same choice due to the tools I'd need. And the space. And it'd be nice to have a garage to work in, instead of not even being a shade tree mechanic (that implies I have a shade tree ... )

RwP

dakotakeith

Discussion Starter · #14 · May 15, 2016

RalphP said:
Well, just as a note, that book I linked to includes the 7.25" diff (front/rear doesn't matter for most of the instructions).

But yah, I've made the same choice due to the tools I'd need. And the space. And it'd be nice to have a garage to work in, instead of not even being a shade tree mechanic (that implies I have a shade tree ... )

RwP

Yes!
I too have only a shade tree. If I had a garage(or a basement for that matter) I would probably be more motivated to tear it down, but I'm not, so I'll pay to have it done.

RalphP

· #15 · May 15, 2016

dakotakeith said:
Yes!
I too have only a shade tree. If I had a garage(or a basement for that matter) I would probably be more motivated to tear it down, but I'm not, so I'll pay to have it done.

I don't even have the shade tree *grins* Literally.

RwP

underwood43x

· #16 · May 16, 2016

i had to do mine on my durango 2 months ago taking it all out is a pain but its fairly easy to put back in. my pinion bearing went then i kept driving it for 7/8 months and it just popped. threw it in 4wd brought it home and it sat for a couple weeks because i lost time but i had to replace everything in the end from it sitting but here are the old gears they have been outside for a little while

See less See more

dakotakeith

Discussion Starter · #17 · May 16, 2016

underwood43x said:
i had to do mine on my durango 2 months ago taking it all out is a pain but its fairly easy to put back in. my pinion bearing went then i kept driving it for 7/8 months and it just popped. threw it in 4wd brought it home and it sat for a couple weeks because i lost time but i had to replace everything in the end from it sitting but here are the old gears they have been outside for a little while

Thanks for sharing! I still think this is beyond my ability, but I'm curious. Where did you buy all of the gears and was that more cost effective than replacing the entire differential, OR is this considered a new differential, assembly required? The thing that gives me pause is the possibility of having to use shims.

underwood43x

· #18 · May 17, 2016

dakotakeith said:
Thanks for sharing! I still think this is beyond my ability, but I'm curious. Where did you buy all of the gears and was that more cost effective than replacing the entire differential, OR is this considered a new differential, assembly required? The thing that gives me pause is the possibility of having to use shims.

i had an extra 9.25 rear end lying around out of a 03 and used the gears and diff out of that. i dont know what the case is for yours (ive done a 95 suburban when i was in boces and my own truck and ive seen exploded diff housings from too large of tires and chewed up gears) but if your diff is still good but gears are shot just do the gears and new bearings (autozone/ yukon gears makes a good kit) if your diff exploded ebay or buy a used one and buy a pinion kit. i just reused gears and got a carquest bearing kit

underwood43x

· #19 · May 17, 2016 (Edited)

the only hard part is getting the diff out then back in. then adjust the carrier so the gears meet in the center of eachother and torque down your pinion... thats the only thing i for got to do drove it down the road and it hummed when i let off the gas. had my unlce ream the thing down since he has more weight then me and it has not hummed and is now sporting 33s after i broke in the gears (normal driving for 3/4 days then retorque everything and change oil with normal tires which is recommended )and i never had to use shims but every truck is different. has lasted through trails, red light racing, and small towing. havent thrown a derby car behind it or taken it on a 2 hr drive yet to really test it

dakotakeith

Discussion Starter · #20 · May 18, 2016

underwood43x said:
the only hard part is getting the diff out then back in. then adjust the carrier so the gears meet in the center of eachother and torque down your pinion... thats the only thing i for got to do drove it down the road and it hummed when i let off the gas. had my unlce ream the thing down since he has more weight then me and it has not hummed and is now sporting 33s after i broke in the gears (normal driving for 3/4 days then retorque everything and change oil with normal tires which is recommended )and i never had to use shims but every truck is different. has lasted through trails, red light racing, and small towing. havent thrown a derby car behind it or taken it on a 2 hr drive yet to really test it

What specialized tools did you need if any? I don't own or have access to hydraulic presses or anything. Were you able to replace the bearings with just regular shop tools and a vice?

1 - 20 of 55 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.